Heathkit SB-10 Series Troubleshooting Manual
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Heathkit SB-10 Series Troubleshooting Manual

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Heathkit HW-101
and SB-10x
Restoration and
Troubleshooting
Revised December 17, 2021

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Summary of Contents for Heathkit SB-10 Series

  • Page 1: Heathkit Hw-101 And Sb-10X Restoration And Troubleshooting

    Heathkit HW-101 and SB-10x Restoration and Troubleshooting Revised December 17, 2021...
  • Page 2 EVISION ISTORY 2021/1/9: Added modification section regarding use of an external VFO to provide split frequency operation (within the same band). 2021/1/9: Significant cleanup work on MS Word’s handling of list numbering 2021/1/8: Added instructions for confirming bandpass filter response using sweep generator and a couple of photos of one radio’s response for reference.

  • Page 3: Table Of Contents

    Contents: Heathkit HW-101 and SB-10x Restoration and Troubleshooting.......1 a)History of the HW-101....................14 a.1.The SB-series and HW-series (Wikipedia)..............15 a.2.Comparison of Various Models..................16 a.3.SB Series vs HW series....................16 a.3.1.RF Amp and 1st Receiver Mixer........................17 a.3.2.SB-101/SB-102 LMO Power Source......................18 a.3.3.Sideband Bias Circuit........................... 18 a.3.4.Accessory Socket............................
  • Page 4 A 50 nonreactive dummy load that is capable of 100 watts dissipation, such as the Heathkit Model HN-31. Do not use light bulbs as a dummy load, as their resistance varies radically with voltage..............32 A receiver capable of receiving WWV, such as the Heath Model GR-54, at 2.5, 5, 10, or 15 MHz.
  • Page 5 s.2.1.Final Heterodyne Oscillator Alignment......................38 s.2.2.Driver Neutralization Adjustment........................38 s.3.LMO Shifter Adjustment....................39 t)Uneven Response Across the Band / Bandpass Filter...........40 t.1.8395 to 8895 KHz Bandpass Filter..................40 t.1.1.Measuring the Bandpass Filter Response (Simple Method).................41 t.1.2.Measuring the Bandpass Filter Response (Sweep Analysis)................41 u)Signal Level Measurements..................44 u.1.Receive Signal Levels....................44 u.1.1.Carrier and Heterodyne Oscillator Levels.....................44 u.1.2.Receive Audio Signal Levels........................
  • Page 6 Figure of Merit............................60 x.2.Summation........................60 y)Heathkit “S” Meter Circuit..................61 y.1.“S” Meter vs. AVC Voltage.....................62 y.2.AVC and “S” Meter Calibration..................63 z)Servicing Procedures....................64 z.1.Front Panel Remove and Replace.................64 z.1.1.Front Panel Removal............................ 64 z.1.2.Front Panel Installation..........................65 a)Make sure that the preselector shaft has these items installed in the following order facing back from the panel: a flat washer, a lock washer, the nut and two rubber “O”...
  • Page 7 RCA Male Adapter........................97 ac.9.SB-100 CW Filter Modification..................98 ac.10.Using an External VFO for Split Frequency Operation..........100 ad)Heathkit Filters......................101 ad.1. Heathkit Filter Measurements...................102 ad.2.SSB Filter 404-200 Circuit..................104 ad.3.SSB Filter 404-283 Circuit..................105 ae)Printed Circuit Boards (PCBs)................107 HW & SB Series Manual...
  • Page 8 Remove and Replace........................122 af.2.2.Heath Tube-Type LMO Repair........................124 af.2.3.Photos Showing Added Grounding Braid....................127 af.2.4.Repairing and Recalibrating a Stuck LMO....................130 af.2.5.Heathkit SB-102 Transceiver LMO Stability Fix..................132 ag)Matching Heathkit Paint..................133 ag.1.1.Matching Heathkit Paint: Part 1........................133 ag.1.2.Matching Heathkit Paint: Part 2........................134 HW &...
  • Page 9 Heathkit Paint: Part 3........................135 ah)HW-101 and SB-10x Service Bulletins..............136 ah.1.HW-101 Service Bulletins...................136 ah.1.1.HW-101-1: VFO Drift..........................136 ah.1.2.HW-101-2: Repeated Heterodyne Oscillator Tube Failure Inadequate USB-LSB Frequency Shift..136 ah.1.3.HW-101-3: Carrier Null Control Failure....................136 ah.1.4.HW-101-4: Low Output on 40 Meters.......................136 ah.1.5.HW-101-4: Low Output on 40 Meters.......................137 ah.1.6.HW-101-5: Alternate Method of Neutralizing the Final Amplifiers............137...
  • Page 10 ah.1.39.HW-101-35: Poor IF Sensitivity......................145 ah.1.40.HW-101-36: Receiver Recovery Slow....................145 ah.1.41.HW-101-37: R-940 Shorting To Shield....................145 ah.1.42.HW-101-38: Poor Carrier Suppression....................145 ah.1.43.HW-101-39: Identification of The 6146a Tubes..................146 ah.1.44.HW-101-40: Noise or Static From Speaker When Chassis Tapped Lightly...........146 ah.1.45.HW-101-41: Relay Chatter in Any Setting of The VOX Sensitivity Control..........146 ah.1.46.HW-101-42: Unit "Warbles"...
  • Page 11 ah.1.82.HW-101-78: Tune Control Slips......................158 ah.1.83.HW-101-79: Driver Stage Oscillates on 15 Meters.................158 ah.1.84.HW-101-80: Low Transmitter Output Due to Low VFO Output..............158 ah.1.85.HW-101-81: Preselector Capacitors Won’t Take Solder................159 ah.1.86.HW-101-82: S Meter Drifts; IF Oscillates....................159 ah.1.87.HW-101-83: Oscillation on 15 Meters.....................159 ah.1.88.HW-101-84: R1, R6 and R7 Out of Tolerance or Open................159 ah.1.89.HW-101-85: VOX Activates When Mike Not Connected................160 ah.2.SB-100 Service Bulletins....................161 ah.2.1.SB-100-1: Diode Leakage in The SB-100, SB-101, HW-100..............161...
  • Page 12 ah.4.4.SB-102-4: LMO Instability......................... 176 ah.4.5.SB-102-5: Low 40 Meter Output.......................176 ah.4.6.SB-102-6: SB & HW Series Audio Preamplifier & VOX Circuit Trouble Shooting Guide......177 ah.4.7.SB-102-7: SB & HW Series Instability & Corrective Information..............178 ah.4.8.SB-102-8: Alternate Method of Neutralizing the Final Amplifiers.............179 ah.4.9.SB-102-9: Oscillations or Low Drive......................180 ah.4.10.SB-102-10: Self Oscillations Occurring After Installation of Steel Comb Brackets.........180 ah.4.11.SB-102-14: Relays Remain Energized After Transmit Condition............180 ah.4.12.SB-102-15: Poor AGC Action.........................
  • Page 13 Tables: HW & SB Series Manual Page 13...

  • Page 14: A)History Of The Hw-101

    Heath was instrumental in planting the technology interest seed in many future engineers and technicians. The AT-1 transmitter of the early 50's was the first Heathkit amateur product. (I had one back then, although I didn't build it). It was followed by the hugely successful DX-100 transmitter, all 100 pounds of it! It was a plate-modulated AM/CW rig that used a pair of 6146 tube finals, just like the HW-101.

  • Page 15: A.1.The Sb-Series And Hw-Series (Wikipedia)

    The HW-100: The Heathkit HW-100 was an attempt, and a very good one, to reduce the cost of the SB series transceivers. The circuitry and specifications were very similar, but some shortcuts were taken to reduce the cost. These were mainly in the cabinet, the VFO, and the lack of a CW filter.

  • Page 16: A.2.Comparison Of Various Models

    But by designing them as kits and using less expensive construction, Heathkit could offer these units at much lower prices. The pair sold for $590 that first year (equivalent to about $4100 today). The matching SB-200 linear amplifier completed the line for 1965.

  • Page 17: A.3.1.Rf Amp And 1St Receiver Mixer

    Bias setting, and S Meter zero adjustment. On the HW series, these controls are accessed through openings in the right side lower cabinet. The HW series uses a builder assembled VFO with a circular dial and frequency calibrations every 5 KHz. The dial reduction drive consists of two Jackson venier drives. The SB series used a preassembled LMO with a circular dial having calibration marks every 1 KHz.

  • Page 18: A.3.2.Sb-101/Sb-102 Lmo Power Source

    "static" signal that occurred with or without the antenna attached. Replacing the defective tube(s) eliminated the problem. I experienced this problem in one of my HW- 101s. Turned out both V10 and V11 were both shorted internally. The price of a 6HS6 is a bit steep, $18 (www.vacuumtubes.net price), higher (www.vacuumtubes.net price).

  • Page 19: A.3.6.Sb-102 Vs. Hw-101

    a.3.6. SB-102 vs. HW-101 What's the difference between an HW-101 and an SB-102? Well, first off, the obvious is the physical appearance (front panel and both top and bottom covers). The HW-101 can only be used with the internal LMO where the SB-102 can use both internal and external LMOs by the flick of a front panel switch.

  • Page 20: A.3.7.Power Supply

    a.3.7. Power Supply The SB-100, 101, and 102 along with the HW-100 and HW-101, have the same basic circuitry and require the same power supply, the HP-23/PS-23 series of power supplies. HW & SB History revised 12/17/2021 Page 20...

  • Page 21: B)General Inspection And Restoration Checklist

    General Inspection and Restoration Checklist This section describes a general guide to beginning restoration. Strong Recommendation: Use a power strip to turn all vintage equipment on and off rather than the built-in on-off switch. This will help preserve the life of these hard to find switches.
  • Page 22 6. 10uf @ 50v capacitor on the Modulator board (C2 on SB series) 7. 10uf @ 50v capacitor on the Bandpass board (C212 on SB series) 8. SB-102 only: two 500uf @ 25v (C941 and C942 located on LMO assembly) Tighten all screws on printed the circuit boards.

  • Page 23: B.2.Resistance And Voltage Checks

    If the meter was removed from the front panel, reinstall it before reinstalling the panel (it’s easier to get to the lower mounting screws while the panel is out) If the LMO dial was removed, reinstall it before replacing the front panel Make sure the LMO tuning shaft and bushing positioned loosely on the metal ring of the circular dial before reinstalling the front panel.

  • Page 24: B.3.Receiver Alignment

    Measure the Heterodyne Oscillator level on all bands (looking for dead crystals or gross tuning issues). Check that both USB and LSB oscillators function and log the level (note: the plate load resistors may have drifted higher in value reducing the oscillator output level) b.3.
  • Page 25 Measure and record receiver sensitivity on each band (spec says better than 0.35uv for 10dB S+N)/N (see ) Measure and record input level required for “S9” meter reading on each band. On air checkout General Inspection and Restoration Checklist revised 12/17/2021 Page 25...

  • Page 26: C)General Troubleshooting Tips

    General Troubleshooting Tips This section provides some general troubleshooting tips that may be helpful if a rig is not functioning properly. Caution: Potentially lethal voltages are present in most vacuum tube radios. Exercise extreme caution when attempting to service this type of radio. Also, vacuum tubes become very hot during operation and can cause burns.

  • Page 27: C.2.2.Unit Receives On Some Bands But Not Others

    With an antenna connected, there should be a noticeable increase in background noise (hiss or static) as the preselector control is tuned. With the frequency dial set to 200, the 3.5, 7.0 and 14.0 bands should peak with the preselector pointer at approximately the 12 o’clock position.

  • Page 28: D)Transmit Tuning And Operation

    Transmit Tuning and Operation d.1. Initial Transmit Tune-Up The steps of this procedure must be performed for all modes of operation. Set the BAND switch and Main Tuning dial for the desired frequency. Place the METER switch in the PLATE position. Turn the MIC/CW LEVEL control fully counterclockwise.

  • Page 29: D.2.Single Sideband Operation

    outlined in the steps above. Then operate the METER switch between REL PWR and PLATE. The maximum power output (REL PWR) should occur at approximately the same point on the FINAL TUNE knob as the maximum dip in PLATE current. If it does not occur at the same point, DO NOT operate the transmitter until you have re- neutralized the unit as outlined (starting in the left column) in the manual.

  • Page 30: D.3.Cw Operation

    1. While speaking into the microphone, turn the VOX SENS control to just beyond a setting that will energize the relays. Be sure this control is not set so high that it will allow background noise to trip the relays. 2.
  • Page 31 4. NOTE: Be sure the VOX DELAY control is adjusted so the relays do not open after each character is sent. Set the MIC/CW LEVEL control to the minimum position that produces full output (Plate current should be 225-250 ma). Transmit Tuning and Operation revised 12/17/2021 Page 31...

  • Page 32: E)Alignment

     A 50  nonreactive dummy load that is capable of 100 watts dissipation, such as the Heathkit Model HN-31. Do not use light bulbs as a dummy load, as their resistance varies radically with voltage.
  • Page 33 l) FREQ CONTROL - LOCKED NORMAL. m) RF GAIN - fully clockwise. n) FILTER - SSB. o) METER - ALC. p) AF GAIN - 9 o’clock position. p.1. S-Meter Adjustment After a few minutes warmup, adjust the METER ZERO control (on the IF circuit board directly behind the FREQ CONTROL switch) for a zero reading on the panel meter.
  • Page 34 Set the FUNCTION switch to CAL and the BAND switch to 3.5, then turn the Main Tuning dial back and forth around 3.7 MHz to get the loudest signal. Check for the calibrate Signal by turning the FUNCTION switch to VOX and back to CAL; the signal should stop and then start again and should peak with the DRIVER PRESELECTOR.
  • Page 35 Figure 1. Driver Grid and Plate Coil Configuration The driver grid and driver plate coils will be adjusted in the following steps. The coil locations are marked on the shield cover at the bottom of the chassis. These coils must be adjusted in the proper sequence as follows: 1.
  • Page 36 Set the BAND switch at 7.0, the Main tuning dial at 7.2 MHz, and the DRlVER- PRESELECTOR to the 7.2 position. Note: A Heathkit service bulletin HW-101-48 recommended setting the Driver- Preselector knob to the 1 o’clock position rather than the 2 o’clock position shown to ensure that the Driver-Preselector could be peaked at both ends of the band.
  • Page 37 FREQ CONTROL - LOCKED NORMAL METER - PLATE. Press the PTT microphone button and turn the BIAS ADJUST control in the Transceiver for a plate current reading of 50 ma If the meter reads more than 100 ma, do not press the microphone button more than a few seconds at one time, until the plate current has been properly adjusted.

  • Page 38: S.2.1.Final Heterodyne Oscillator Alignment

    Adjust the CARRIER NULL capacitor for minimum RF output. necessary, repeat the ( ) If adjustments of the CARRIER NULL control, and the CARRIER NULL capacitor until the RF output or null reading is about the same on both the LSB and USB positions of the MODE switch.

  • Page 39: S.3.Lmo Shifter Adjustment

    s.3. LMO Shifter Adjustment 1. Adjust the Main tuning dial to 3.7 MHz (BAND switch to 3.5, the upper dial at 2, and the circular dial to 0). 2. Set the FUNCTION switch to CAL. 3. Turn the MODE switch to USB. 4.

  • Page 40: T)Uneven Response Across The Band / Bandpass Filter

    NOTE: Heathkit Service Bulletin HW-101-56 discusses this problem and describes a method to perform a sweep alignment of the Bandpass Filter T202. I have not found a copy of this service bulletin that contains the figures it references.

  • Page 41: T.1.1.Measuring The Bandpass Filter Response (Simple Method)

    t.1.1. Measuring the Bandpass Filter Response (Simple Method) The simplest approach to measuring the response of the bandpass filter is as follows: Test Setup SB-102: Measure RF Signal at Driver Output jack on the rear panel. Remove the 6146 Screen voltage by removing MOLEX plug on rear. This makes it easier on the finals while performing the measurements.
  • Page 42 Receive Mode Bandpass Response With power off, connect the output of the sweep (tracking) generator to V11 pin 1 through a suitable DC blocking capacitor. Connect the demodulator probe or spectrum analyzer input to V12 pin 2 also through a suitable DC blocking capacitor. Set the center frequency to 8645 KHz with a sweep width of 2 MHz.
  • Page 43 Transmit Mode Bandpass Response With power off, connect the output of the sweep or tracking generator to V5 pin 2 through a suitable DC blocking capacitor. Connect the demodulator probe or spectrum analyzer input to V6 pin 1 also through a suitable DC blocking capacitor. Set the center frequency to 8645 KHz with a sweep width of 2 MHz.

  • Page 44: U)Signal Level Measurements

    Signal Level Measurements The purpose of these measurements is to determine the receiver gain through various stages. This can help isolate problems due to insufficient gain in a particular stage in the signal path. I have not found any published values, so the expected values are based on the average measurements from a number of different rigs.

  • Page 45: U.1.2.Receive Audio Signal Levels

    u.1.2. Receive Audio Signal Levels The purpose of these two measurements is to determine the gain of the receive audio stages associated with V14. This is done by measuring the audio input levels needed to produce 500 mw audio output into audio level meter or dummy load (500 mw = 2 VAC across an 8...
  • Page 46 AF Gain control set to a comfortable listening level AC Voltmeter connected to top of AF Gain control Band Switch set to 3.5 (80 meters) Frequency dial set to 3700 KHz. Disable the AVC by Disconnect the two yellow wires from pad 13 on the IF board (rear left as viewed from the bottom of the chassis) and connect them to ground with a jumper wire.
  • Page 47 Injection Test Input Signal Injection Expected Input Measured Input Point Injection Point Frequency for 2 VAC at top for 2 VAC at top of AF Gain Pot of AF Gain Pot ② Product Detector V13 pin 8 3,395 KHz -8 dBm Input ③...
  • Page 48 Table 3. dBm to Microvolt Conversion Chart Signal Level Measurements Page 48...

  • Page 49: V.2.Transmit Signal Levels

    Transmit Signal Levels v.2.1. Transmit and VOX Audio Level Troubleshooting Guide Source: Heathkit Service Bulletin HW-101-6 It is assumed that the basic steps such as making DC voltage measurement, checking tubes & reviewing the soldering have been completed. The following information was compiled from the above transceivers in the 80M LSB position.

  • Page 50: V.2.2.Transmit Rf Signal Levels

    Remove 6146 Screen voltage by disconnecting R920 (100 ohm to Pin 3 on 6146s) - easier on finals. TUNE mode, Peak the DRIVER/PRESELECTOR for maximum drive. RF Volts measured with Heathkit VTVM & RF Probe. Scope measured with wideband scope using 10x probe...
  • Page 51 21.0 21,200 KHz 3.90 11.03 28.0 28,200 KHz 4.20 11.88 28.5 28,700 KHz 4.20 11.88 29.0 29,200 KHz 4.20 11.88 29.5 29,700 KHz 4.20 11.88 Signal Level Measurements Page 51...

  • Page 52: W)Signal To Noise Ratio (Snr)

    w) Signal to Noise Ratio (SNR) w.1. Signal to Noise Ratio (Theory) The noise performance and hence the signal to noise ratio is a key parameter for any radio receiver. The signal to noise ratio, or SNR as it is often termed is a measure of the sensitivity performance of a receiver.

  • Page 53: W.1.3.Effect Of Bandwidth On Snr

    this ratio, the input signal level must be given. This is usually expressed in microvolts. Typically a certain input level required to give a 10 dB signal to noise ratio is specified. It is more usual to see a signal to noise ratio expressed in a logarithmic basis using decibels: If all levels are expressed in decibels, then the formula can be simplified to: The power levels may be expressed in levels such as dBm (decibels relative to a...

  • Page 54: W.2.Measuring Signal To Noise Ratio (Snr)

    noise ratio, SNR are made. A calibrated RF signal generator is used as a signal source for the receiver. It must have an accurate method of setting the output level down to very low signal levels. Then at the output of the receiver a true RMS AC voltmeter is used to measure the output level.

  • Page 55: W.2.2.Test Setup

    Connecting cables. w.2.2. Test Setup The illustration below shows the test setup. The headphones let you listen to the receiver audio at the same time you measure the level. Caution: Before you connect your transceiver to the signal generator, render your transceiver unable to transmit by disconnecting the MIC and KEY.
  • Page 56 Signal to Noise Ratio (SNR) Page 56...
  • Page 57 Band Frequency Signal Gen Output (dBm) Signal Gen Output ( volts) 3,750 7,250 14,250 21,250 28,750 Table 5. Signal to Noise Ratio (S+N/N) If the CW Filter is installed, as a bonus measurement, you might wish to switch to CW mode, and tune to the signal generator (if the CS Filter is not installed, you can do this in SSB mode).

  • Page 58: X)Testing Gain, S+N/N, Agc Threshold And Figure Of Merit

    Switching in the speaker allows you to quickly find the signal when you change frequencies. Note: Unless it has been modified, the headphone jack on the Heathkit transceivers is designed for high-impedance headphones and should not be used for audio output measurements.

  • Page 59: X.1.Testing

    Figure 6. Receiver Test Setup x.1. Testing I’ll give you the processes as they relate to the Hallicrafters SR series receivers. You can figure out the math and apply the process to whatever receiver you wish. ALSO NOTE THE FOLLOWING APPLIES TO HF BAND RECIEVERS. x.1.1.

  • Page 60: X.1.4.Agc Figure Of Merit

    receivers. Peak the receiver, set the RF gain to max, Set the AF gain to 500mw out. Decrease the input signal until the audio power out drops 1dB (down to 400mw or decrease of 20%). That is the AGC threshold point. Some receivers like the SR-400A have an adjustment for setting the threshold.

  • Page 61: Y)Heathkit "S" Meter Circuit

    Heathkit “S” Meter Circuit Refer to the following diagram for the “S” meter circuitry. R104 and R105 provide a small positive reference voltage for the “S” meter based on the cathode current of V3. As the AVC voltage goes more negative in response to a received signal, the negative bias on the grid increases reducing the current flow (gain) through V3, the 1 IF amp.

  • Page 62: Y.1."S" Meter Vs. Avc Voltage

    75% on the value measured at R415. If this is not the case, it may be that one, or both, of the IF amplifier tubes is gassy creating a positive voltage that bucks the AVC voltage. Heathkit “S” Meter Circuit Page 62...

  • Page 63: Y.2.Avc And "S" Meter Calibration

    7,200 14,200 21,200 28,700 Input dBm  volts AVC Voltage Input dBm  volts AVC Voltage Input dBm  volts AVC Voltage S9+20 Input dBm  volts AVC Voltage Table 8. "S" Meter Calibration Heathkit “S” Meter Circuit Page 63...

  • Page 64: Z)Servicing Procedures

    Servicing Procedures This section documents remove and replace procedures for several non-obvious components. z.1. Front Panel Remove and Replace The following steps list the procedure to remove and replace the front panel on an SB series radio. z.1.1. Front Panel Removal 1.

  • Page 65: Z.1.2.Front Panel Installation

    z.1.2. Front Panel Installation Figure 8. Front Panel Installation 1. Mount the meter to the front panel, if it is not already installed. 2. Make sure that the internal lock washers and nuts are positioned on the Preselector and PA Tune shafts a) Make sure that the preselector shaft has these items installed in the following order facing back from the panel: a flat washer, a lock washer, the nut and two...

  • Page 66: A)During This Procedure, Be Especially Careful Not To Place Too Much Pressure On The Main Tuning Dial

    a) During this procedure, be especially careful not to place too much pressure on the main tuning dial. b) During this procedure, be especially careful not to place too much pressure on the zero set shaft. Gently slide the front panel over all of the control shafts, paying particular attention to the Preselector and PA Tune shafts as they will tend to be pulled down by the rubber “O”...

  • Page 67: Z.2.Front Panel Escutcheon Mounting

    z.2. Front Panel Escutcheon Mounting The following procedure was taken from SB-101 Assembly Manual but should apply equally to any SB-series product using the same dial mechanism. NOTE: If the front panel is not installed, it may be easier to mount the escutcheon to the front panel before installing the front panel.
  • Page 68 the large flat washer, lock washer, and nut. NOTE: The amount of torque required to turn the circular dial can be adjusted by moving the dial drive bushing up or down. 6. Push the zero set drive pulley flush with the inside of the dial escutcheon; then install the 7/16"...

  • Page 69: Z.3.Sb Series Dial Mechanism

    z.3. SB Series Dial Mechanism The following section is taken from the SB-101 Assembly Manual and describes installation, adjustment and calibration of the dial mechanism. z.3.1. Installation of the Spiral Groove Follower Mechanism 1. Refer to Detail 3-7A and install the nylon spiral follower on the dial pointer drive arm. Use a 3-48 x 1/8"...

  • Page 70: Down. Retighten The Screws

    3. Position the circular dial on the LMO shaft with the "90" marking straight up, and position the nylon spiral follower in the first groove (nearest the hub) of the circular dial; then tighten the setscrew. NOTE: If the nylon follower will not fit into the first groove of the circular dial, loosen the hardware that secures the dial pointer drive arm to the chassis.

  • Page 71: Pointer Is At The "5" Marking. Retighten The Screws

    a) If the dial pointer is to the left of the "5" marking, loosen the dial pointer drive arm mounting screws and move the dial pointer drive arm base up until the dial pointer is at the "5" marking. Retighten the screws. ab)If the dial pointer is to the right of the "5"...
  • Page 72 If the dial mechanism slips while tuning, it may be that the beveled pulley is not gripping the metal ring sufficiently. To remedy this, loosen the nut on the front of the shaft slightly and move the bushing and shaft down very slightly. If the pulley on the end of the main tuning shaft is positioned to the front of the metal ring, the dial will not move unless the main tuning shaft is pushed in slightly.

  • Page 73: Ab.1.3.Drag When Rotating Main Tuning Knob

    ab.1.3. Drag When Rotating Main Tuning Knob Sometimes when turning the main tuning knob, it may be noticed that there is an excessive amount of drag, or a periodic increase in the amount of force required to turn the knob. Assuming that the problem is not in the LMO itself, here are a couple of things to check.

  • Page 74: Ab.1.4.Circular Dial Wobble

    ab.1.4. Circular Dial Wobble It may be noticed that the main tuning mechanism exhibits an uneven drag or resistance as the LMO is tuned through its range. This drag may become more pronounced as the tuning approaches the 5 end of the slide rule dial. If so, here is one possible cause. Upon investigation, it was determined that the circular dial had a “wobble”...

  • Page 75: Ab.1.5.Spiral Groove Nylon Follower Replacement

    ab.1.5. Spiral Groove Nylon Follower Replacement In several instances, the small tip on the nylon follower that rides in the spiral groove of the circular dial may have been damaged. When this occurs, the follower mechanism and slide rule dial no longer function. It is possible to fashion a replacement using a threaded nylon standoff insulator designed for mounting printed...

  • Page 76: Ab.1.6.Zero Set Dial Mechanism And Pulley

    ab.1.6. Zero Set Dial Mechanism and Pulley It may be found that the rear washer of the zero set pulley has broken off and it is no longer possible to move the plastic window with the dial cursor. The pulley consists of a front washer, spacer, and rear washer.
  • Page 77 If the pinch roller was just slipping due to age the fix is to add some "grip" material like silicon to the inner surface of the pinch roller or to the outer surface of the dial window. The dial window tracks in approx 2/3 of the depth of the pinch roller. Servicing Procedures Page 77...

  • Page 78: Ab.1.7.Repairing The Center Hub

    The following is my best attempt at describing how I restored the broken tuning dial on an otherwise nice Heathkit SB-101. The end result was a super-smooth operating dial mechanism, that's robust enough to outlive the rest of the radio.
  • Page 79 I did the complete fill of the pocket because I wanted the area with cracks in the transparent pocket to be reinforced by the J-B Weld. You could avoid the need to machine out the fill for the pinch roller drive wheel by just using a round cylinder form around the hub that leaves at least 3/4"-wide clearance band at the outer edge of the pocket, and just fill the area between the hub and the inner side of the cylinder form with J-B Weld.

  • Page 80: Ab.2.Knob Inlays

    ab.2. Knob Inlays  The small knob spun aluminum inlay is 9/16” diameter  The large knob spun aluminum inlay is 1½” diameter (HW and SB series) Occasionally, someone produces inlays that show up online. Servicing Procedures Page 80...

  • Page 81: Ab.3.Pa Load Capacitor Remove And Replace

    ab.3. PA Load Capacitor Remove and Replace 1. Remove the top and rear covers to the PA cage 2. Remove the load cap "O" ring and pulley (the pulley uses the same 5/64” Allen wrench as the knobs) 3. Under the chassis, disconnect the leads to the old load cap (at three different places). 4.

  • Page 82: Ab.4.Function Switch (A.c. Switch)

    ab.4. Function Switch (A.C. Switch) It is not unusual for the AC portion of the Function switch to fail with the result that the radio cannot be turned on or off with the switch. Unfortunately, it is usually not possible to find a replacement for the AC switch portion.
  • Page 83 Figure 11. Modified Function Switch Servicing Procedures Page 83...

  • Page 84: Ac)Modifications

    ac) Modifications While many of the modifications in this section are oriented toward the HW-101, they should apply equally well to the SB series. As with all vintage radios, one should consider whether a certain modification is desirable, or not. Many thanks to Lenny WB8JCJ for his help in editing, image scanning, input, and implementation of these changes into his HW-101.

  • Page 85: Ac.1.Conversion To Low-Z Headphones

    ac.1. Conversion to Low-Z Headphones: These rigs are designed to be used with Hi-Z headphones, but if low-Z phones are used the outboard speaker will not mute completely with the phones connected. To convert to low-Z phones, make the following wiring changes referring to (Figure 12. Modification for Low Z Headphones) of this document, and pictorial 8-4 (foldout from page 53), and pictorial 8-5 (foldout from page 67) of the HW-101 manual: 1.

  • Page 86: Ac.2.Improved Cw Operation

    ac.2. Improved CW Operation: In the CW mode the rig’s relays are energized by the CW sidetone amplifier's sidetone output driving the VOX relay amplifier. The audio (sidetone) drive to the VOX amp is a bit on the low side for fast relay action, and at speeds approaching 20 wpm the first dot sent is heard in the sidetone but isn’t transmitted due to the slow relay response time.
  • Page 87 Figure 13. Audio Circuit Board Modifications Now during receive, the sidetone will be bypassed to ground by the normally closed contact on RL1. During transmit, RL1 opens and the sidetone works normally. Modifications Page 87...

  • Page 88: Ac.3.Transmit Improvements

    ac.3. Transmit Improvements The transmitter audio quality can be improved by changing the value of coupling capacitor C11 on the modulator board from .001 μfd to .01 μfd (see Figure 15. Modulator Circuit Board on page 86). This will increase the low frequency response and give the transmit audio a little more “body”.
  • Page 89 Figure 14. IF Circuit Board Modifications Modifications Page 89...

  • Page 90: Ac.4.Receive Improvements

    ac.4. Receive Improvements The receiver’s strong signal-handling capability and audio quality can be vastly improved by the following changes: During alignment check to see if, while adjusting T-102 (see Figure 14. IF Circuit Board Modifications on page 84), there are two points where the transformer can be peaked -- one spot for transmit and a slightly different setting for receive.
  • Page 91 Figure 15. Modulator Circuit Board Modifications Additional rolloff of the high frequency response will remove the raspy nature of the receive audio, and this is accomplished by changing the value of capacitor C119 on the I.F. board from 500pf to .001 μfd (see Figure 14. IF Circuit Board Modifications on page 84).

  • Page 92: Ac.6.I.f. Filter Passband Improvements

    Figure 16. Bandpass Board Modifications ac.6. I.F. Filter Passband Improvements I believe the crystals that Heath supplied for the carrier oscillator were of fairly wide tolerance, thus the frequencies of the LSB/USB/CW carrier injection may not be properly positioned on the slope of the I.F. filter. This can affect both the receive and transmit audio response to a great degree.
  • Page 93 On my particular HW-101, the actual measured carrier oscillator frequencies were 3393.8 kHz LSB, 3395.9 kHz USB, and 3395.17 kHz for CW. This resulted in a “tinny” sounding audio response in LSB compared to USB, and a very “bassy” sounding USB. The CW power output while using the SSB filter was 110 watts, but since the CW carrier oscillator injection was so far from the CW filter center-frequency of 3395.4 kHz, the CW power output was 50 watts while using the CW filter!

  • Page 94: Ac.7.Stabilizing Meter Zero Settings

    LSB, 3396.31 kHz USB, and 3395.38 for CW. The audio is perfectly balanced when switching between sidebands, indicating a true I.F. filter center frequency of Heathkit Crystal Filters of 3394.91 kHz. The CW power output while using the CW filter went from 50 watts to 110 watts.
  • Page 95 Modifications Page 95...

  • Page 96: Ac.8.Antenna Connector

    ac.8. Antenna Connector For a number of reasons, you may want to replace the original RCA style antenna connector with a different style. There are two common replacements. ac.8.1. BNC Connector Some may want to replace the "Ant" RCA phono plug with a round "bulkhead" mount BNC connector.

  • Page 97: Ac.8.3.So-239 To Rca Male Adapter

    ac.8.3. SO-239 to RCA Male Adapter Should you decide to leave the original connector installed while still using cables with the familiar PL-259 connector, adapters are available from Amazon.com, ebay, or other sources. Modifications Page 97...

  • Page 98: Ac.9.Sb-100 Cw Filter Modification

    ac.9. SB-100 CW Filter Modification As pointer out by Mike (W5RKL), the SB-100 can be modified to incorporate the CW/SSB filter switching mechanism that was added to the SB-101 and SB-102 transceivers. While the SB-100 originally used a larger sized filter than the later transceivers To do this, it is necessary to secure the following items (perhaps from a SB-101 or SB- 102 parts chassis (filters and filter mounting bracket not shown in the figure):...
  • Page 99 Figure 17. CW/SSB Filter Switch Assembly Modifications Page 99...

  • Page 100: Ac.10.Using An External Vfo For Split Frequency Operation

    RCA phono jack and mark it ‘EXT VFO IN’. 2. Remove R220 (1K) to remove plate voltage from V5B 3. The Heathkit modification also calls for removal of L202 (36uH) and C222 (100pF) although it is unclear why this would be necessary.

  • Page 101: Ad)Heathkit Filters

    Heathkit Filters Heathkit used two different physical sizes for the filters in the SB/HW transceivers, receiver/transmitter pairs, and SWL receivers. Part no. Model no. Type Bandpass at Bandpass at Used in -6dB -60dB Larger Sized Filters 404-200 2.1 kHz.

  • Page 102: Ad.1. Heathkit Filter Measurements

    Heathkit Filter Measurements This section contains a series of measurements made on one example of each type of Heathkit SB-line crystal filters at 3.395MHz. AM (wide) 404-314 SSB 404-200 CW 404-284-1 Attenuation Low Side High Side Low Side High Side...
  • Page 103 Heathkit Filters Page 103...

  • Page 104: Ad.2.Ssb Filter 404-200 Circuit

    Toroids have an outer diameter of 0.38inches and a thickness of 0.13inches. Material not known. There was no evidence of any varnish on either toroid transformer which was surprising. The internal crystal parameters are shown on the "Crystals for IF Filters" page on this web site. Heathkit Filters Page 104...

  • Page 105: Ad.3.Ssb Filter 404-283 Circuit

    This filter was purchased second hand and received with a fault in the form of a 30dB dip in the passband. Opening up the filter revealed a broken PCB track which has subsequently been repaired and the filter now exhibits the correct overall response. Figure 20. SSB Filter 404-283 Circuit Heathkit Filters Page 105...
  • Page 106 Figure 21. Heathkit Filters The lower right photo shows the repair to the broken track on the top right corner of the PC Board. The top and bottom connections are made to the case and the left and right hand connections are signal in and out.

  • Page 107: Ae)Printed Circuit Boards (Pcbs)

    ae) Printed Circuit Boards (PCBs) The HW and SB series transceivers used a (mostly) common set of printed circuit boards. Because of the similarity among different levels, it is possible that different versions of the same board may have been used during production (i.e., earlier production runs may have used on version of a given board while later production runs may have use a different version, or even two different versions).
  • Page 108 Board Part # Used In Comments Modulator 85-127P221 SB-100, SB-101 85-127-1 SB-101 85-127-2 HW-100, HW-101 85-127-3 SB-102 85-128P222 SB-100 85-128P376 SB-101 85-128-2 SB-101, SB-102 85-128-3 HW-100 85-128-4 R104 and R105 are 47, R106 is 22k, R110 is unused, HW-101 Meter zero pot is 10K and mounted externally 85-128-5 SB-102 R106 changed to 33k, R110 changed to 510...

  • Page 109: Ae.1.Modulator Printed Circuit Board 85-127-X

    ae.1. Modulator Printed Circuit Board 85-127-x I have been able to identify three (or possibly four) different revision levels (1, 2, 3) of this board. ae.1.1. 85-127P221 (SB-100, SB-101) ae.1.2. 85-127-1 (SB-101) ae.1.3. 85-127-2 (HW-100, HW-101) R28 (22k) is the audio input from a phone patch and is not present as the HW-10x series does not support a phone patch.

  • Page 110: Ae.2.If Printed Circuit Board 85-128-X

    ae.2. IF Printed Circuit Board 85-128-x There are five (or possibly four) different revision levels of this board. Some differences are (to be sorted out ...): Revision Level P376 (SB-100) R104 and R105 are 56 R106 is 22k R110 is 330 Meter zero pot is 200...

  • Page 111: Ae.3.Bandpass Printed Circuit Board 85-129-X

    ae.3. Bandpass Printed Circuit Board 85-129-x ae.3.1. 85-129P223 (SB-100) ae.3.2. 85-129-2 (SB-101) ae.3.3. 85-129-3 (HW-100) ae.3.4. 85-129-4 (SB-102) ae.3.5. 85-129-5 (??) ae.3.6. 85-129-6 (HW-101) The components associated with the XTAL oscillator (V5 pins 1, 8, and 9 - R220, R225, crystal Y202, 8- 50pf trimmer cap, C210, C221, C222, L202) are not present and there is no provision for an external LMO/VFO.

  • Page 112: Ae.4.Audio Printed Circuit Board 85-130-X

    ae.4. Audio Printed Circuit Board 85-130-x ae.4.1. 85-130P224 (SB-100, SB-101) ae.4.2. 85-130-1 (SB-101) ae.4.3. 85-130-2 (HW-100) ae.4.4. 85-130-3 (SB-102) ae.4.5. 85-130-4 (HW-101) The CW Sidetone volume is fixed and there is no volume control as on the SB series. Printed Circuit Boards (PCBs) Page 112...

  • Page 113: Ae.5.Rf Driver Printed Circuit Board 85-131-X

    ae.5. RF Driver Printed Circuit Board 85-131-x Printed Circuit Boards (PCBs) Page 113...

  • Page 114: Ae.6.Crystal Switch Board 85-132-X

    ae.6. Crystal Switch Board 85-132-x Printed Circuit Boards (PCBs) Page 114...

  • Page 115: Ae.7.Het Osc, Driver Grid, And Driver Plate Switch Board 85-133-X

    ae.7. Het Osc, Driver Grid, and Driver Plate Switch Board 85-133-x Printed Circuit Boards (PCBs) Page 115...

  • Page 116: Af)Heathkit Linear Master Oscillators (Lmos)

    Heathkit Linear Master Oscillators (LMOs) This section contains information on the Heathkit Linear Master Oscillators used in the SB series of transmitters, receivers, and transceivers. In all cases, the LMO tuning range is from 5.0 MHz to 5.5 MHz with a slight overlap at each end.

  • Page 117: Af.1.1.Heathkit Trw Lmo

    Heathkit TRW LMO Figure 22. Heathkit TRW LMO Heathkit Linear Master Oscillators (LMOs) Page 117...

  • Page 118: Af.1.2.Lmo Part Number 110-13

    LMO Part Number 110-13 This LMO is used on the SB-300 receiver and SB-400 transmitter. Figure 23. LMO Part Number 110-13 Heathkit Linear Master Oscillators (LMOs) Page 118...

  • Page 119: Af.1.3.Lmo Part Number 110-32

    LMO Part Number 110-32 This LMO is used on the SB-100 transceiver and SB-401 transmitter. Figure 24. LMO Part Number 110-32 Heathkit Linear Master Oscillators (LMOs) Page 119...

  • Page 120: Af.1.4.Lmo Part Number 110-40

    LMO Part Number 110-40 This LMO is used on the SB-101 transceiver and SB-301 receiver. Figure 25. LMO Part Number 110-40 Heathkit Linear Master Oscillators (LMOs) Page 120...

  • Page 121: Af.1.5.Sb-102 Lmo (Ver6)

    SB-102 LMO (ver6) This LMO is used on the SB-102 Transceiver. Figure 26. SB-102 LMO (ver6) Heathkit Linear Master Oscillators (LMOs) Page 121...

  • Page 122: Af.2.Lmo Repair And Service Notes

    To replace the LMO use the following procedure. 1. Use a small screwdriver to turn the LMO shaft fully counter clockwise 2. Place the circular dial on the LMO shaft – leave the set screw loose for now Heathkit Linear Master Oscillators (LMOs) Page 122...
  • Page 123 68. 12. It will be necessary to perform the circular dial calibration as described in Dial Calibration on page 67. 13. Replace the large tuning knob and reconnect the power cable. Heathkit Linear Master Oscillators (LMOs) Page 123...

  • Page 124: Af.2.2.Heath Tube-Type Lmo Repair

    Glen E. Zook, K9STH Copyright 2012 by author The tube-type Linear Master Oscillators (“LMO”) used in the Heathkit SB-Line equipment is a very stable and accurate means of controlling the frequency in the equipment. Unfortunately, as the units age, many LMOs develop a “warble” when tuning.
  • Page 125 With the large gear, cut off a length of 8-32 machine screw about 1/2th inch long, so that you just have the thread portion. That is, no “head” on the screw. Heathkit Linear Master Oscillators (LMOs) Page 125...
  • Page 126 Replace the side panel removed before, making sure to replace the “lugs” which mount the LMO to the chassis. Finally, reverse the removal procedure to return the LMO to the unit. Heathkit Linear Master Oscillators (LMOs) Page 126...

  • Page 127: Af.2.3.Photos Showing Added Grounding Braid

    Figure 27. LMO With Added Ground Braid The braid can be seen in the upper left-hand corner of the LMO. This is the version with the larger gear, the Heath part number 110-32. Heathkit Linear Master Oscillators (LMOs) Page 127...
  • Page 128 Figure 28. LMO With Added Ground Braid (Example 2) Again, the braid can be seen in the upper left-hand corner. This is the version of the LMO with the smaller gear, the Heath part number 110-40. Heathkit Linear Master Oscillators (LMOs) Page 128...
  • Page 129 This is the side panel which has to be removed to repair the LMO. Note the “notches” on the left-hand side where the “lugs” which hold the LMO on the chassis are attached. Heathkit Linear Master Oscillators (LMOs) Page 129...

  • Page 130: Af.2.4.Repairing And Recalibrating A Stuck Lmo

    Remove the washers and give them a good cleaning. Heathkit Linear Master Oscillators (LMOs) Page 130...
  • Page 131 I missed in not being the original builder of this rig and a renewed appreciation for the guys at Heath who made it all possible. Heathkit Linear Master Oscillators (LMOs) Page 131...

  • Page 132: Af.2.5.Heathkit Sb-102 Transceiver Lmo Stability Fix

    Heathkit SB-102 Transceiver LMO Stability Fix Source: unknown I noticed many SB-102 solid state VFOs become unstable over the years. In most cases a light bump or tap on the radio will cause it to jump frequency, excessive random mechanical instability especially during warm-up.

  • Page 133: Ag)Matching Heathkit Paint

     N1- Raw Umber - 62 - -  Y3- Deep Gold - - 1 1 I do have the Sherwin-Williams formulas for several of the Heath colors as well as Collins, National, and Hallicrafters. Matching Heathkit PaintHeathkit Linear Master Oscillators (LMOs) Page 133...

  • Page 134: Ag.1.2.Matching Heathkit Paint: Part 2

    The first is the same Krylon Sage Satin and the other is a private brand from Wal Mart (Color Place Rust Control Evergreen #21032). The Sage Satin is Matching Heathkit PaintHeathkit Linear Master Oscillators (LMOs) Page 134...

  • Page 135: Ag.1.3.Matching Heathkit Paint: Part 3

    It's Krylon Indoor/Outdoor Gloss Hunter Green. This isn't an exact match for the original Heathkit paint (which is slightly lighter and, in my opinion, contains a bit more blue), but I find it is close enough for my tastes.

  • Page 136: Ah)Hw-101 And Sb-10X Service Bulletins

    ah) HW-101 and SB-10x Service Bulletins This section contains a compendium of service bulletins for the HW-101, SB-100, SB- 101 and SB-102 transceivers. The HW-101 is included due to the large number of similarities between the HW-101 and SB-10x series of transceivers. ah.1.

  • Page 137: Ah.1.5.Hw-101-4: Low Output On 40 Meters

    SEE BULLETIN NO: SB-102-5 DATED OCTOBER 29, 1973 ah.1.5. HW-101-4: Low Output on 40 Meters OCTOBER 29, 1973 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-4 1. REMOVE the 1-1/2" bare wire from hole 1 on the DRIVER PLATE circuit board & the ground foil of the RF DRIVER board.

  • Page 138: Ah.1.8.Hw-101-6: Sb & Hw Series Audio Preamplifier & Vox Circuit Troubleshooting Guide

    5. Set the function switch to tune. 6. Rotate the level control fully clockwise. 7. Adjust the preselector control for a maximum indication on the VTVM. 8. Adjust the final control for a maximum indication on the VTVM, with the load control set at the 50 ohm position.

  • Page 139: Ah.1.11.Hw-101-9: Self Oscillations Occurring After Installation Of Steel Comb Brackets

    ah.1.11. HW-101-9: Self Oscillations Occurring After Installation of Steel Comb Brackets MAY 2, 1975 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-9 SEE BULLETIN NO: SB-100-6 DATED MAY 2, 1975 (see Page 153) ah.1.12. HW-101-10: S-Meter Drift MARCH 26, 1976 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-10 To bring the meter drift to an acceptable level, install the following: CHANGE: R107 from 100K Ohm 1/2 Watt to 100K 1 Watt [PN 1-28-1]...

  • Page 140: Ah.1.16.Hw-101-14: Improve Alc Adjustment

    Due to the low percentage of the tested diodes meeting the low reverse-current spec, the germanium diodes in this kit are being changed as follows: CR1, CR2, CR3 and CR4 in the Balanced Modulator circuit are being changed to [PN 56-87] hot-carrier diodes. CR901, CR941 and CR201 are being changed to non-selected [PN 56-26] diodes.

  • Page 141: Bands

    If V12 is an Elmenco tube, replace V12 [PN 411-124] with a GE tube. (NOTE: If a GE tube is not available, it may be necessary to try several Elmenco tubes for a satisfactory result.) ah.1.20. HW-101-18: RF Choke in Final Plate Circuit Overheats or Difficult to Neutralize on 10 Meter &...

  • Page 142: Ah.1.24.Hw-101-22: Relative Power Meter Pegs On 15 And 10 Meter

    To correct, INSTALL: .005 uf capacitor [PN 21-57] in parallel with the .2 uf capacitor at C3. Install only as needed. ah.1.24. HW-101-22: Relative Power Meter Pegs on 15 And 10 Meter APRIL 14, 1978 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-22 Diode CR-901 [PN 56-26] should be mounted on terminal strip BR with 1/2"...

  • Page 143: Ah.1.28.Hw-101-26: Receiver Recovery Slow

    Look at the calibrator output [ahead of output diode] with an oscilloscope. Use high input gain and a slow sweep speed. If the upper portion of the sine-wave signal appears choppy or uneven, the Y201 crystal may be at fault. After installation of a new crystal [PN 404-43], recheck with oscilloscope.

  • Page 144: Ah.1.33.Hw-101-30: Loading Capacitor Turns As Plate Capacitor Is Rotated

    Check the belt for being loose or worn and replace as needed. Lubricate the bearing of the variable capacitors. If lubricating the capacitor bearings does not allow the rotor to turn freely, replace the capacitor [PN 26-122]. ah.1.33. HW-101-30: Loading Capacitor Turns as Plate Capacitor is Rotated AUGUST 1, 1978 HW-101 BULLETIN NO: SSB TRANSCEIVER...

  • Page 145: Ah.1.37.Hw-101-33: Alc Meter Reads Below Zero

    ah.1.37. HW-101-33: ALC Meter Reads Below Zero AUGUST 21, 1978 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-33 SEE BULLETIN NO: HW-100-18 DATED AUGUST 21, 1978. ah.1.38. HW-101-34: S Meter Drift AUGUST 22, 1978 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-34 SEE BULLETIN NO: HW-100-17 DATED AUGUST 22, 1978. ah.1.39.

  • Page 146: Ah.1.43.Hw-101-39: Identification Of The 6146A Tubes

    ah.1.43. HW-101-39: Identification of The 6146a Tubes NOVEMBER 20, 1978 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-39 The 6146A tubes [PN 411-75] used at V8 and V9 of this unit are marked '6146A' in white ink on the side of the tube. These tubes may also have '6146B' etched in the galss.

  • Page 147: Ah.1.46.Hw-101-42: Unit "Warbles" When Chassis Is Tapped

    3. Ground the shields to a ground foil near the junction of R213 and R214. ah.1.46. HW-101-42: Unit "Warbles" When Chassis Is Tapped DECEMBER 27, 1978 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-42 This "warble" has been traced to the VFO assembly. This occurs especially when the leads of the C946 and C953 capacitor combination is too long, enabling the capacitors to vibrate.

  • Page 148: Ah.1.51.Hw-101-47: Driver Preselector Won't Peak For Full Output At 7.0 Mhz

    ah.1.51. HW-101-47: Driver Preselector Won't Peak for Full Output at 7.0 MHZ May 15, 1979 HW-101 Bulletin No: SSB Transceiver HW-101-47 See Bulletin No: HW-100-23 Dated May 15, 1979 ah.1.52. HW-101-48: PEC [PN 84-22] No Longer Used May 15, 1979 HW-101 Bulletin No: SSB Transceiver HW-101-48...

  • Page 149: Ah.1.56.Hw-101-52: Vfo Stops Working At High End Of All Bands

    Shows .024uf connected from wht-org-org to ground --- 2.2K ohm resistor in line going to R1 ah.1.56. HW-101-52: VFO Stops Working at High End of All Bands August 15, 1979 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-52 This problem occurs in all modes except LSB. In LSB, the VFO operates okay. To Correct: Change: R947 from 1000 ohm to 470 ohm [PN 6-471] Add: [PN 56-56] diode from gate of Q941 to ground;...

  • Page 150: Ah.1.59.Hw-101-55: Avc Decay Too Fast; S Meter Drops Too Quickly

    Pin 9 of V14 = 1.5v p-p Pin 8 of V14 = 1.5v p-p Pin 6 of V14 = 35v p-p Speaker Jack = .6v p-p Add these voltages to your shop schematic. ah.1.59. HW-101-55: AVC Decay Too Fast; S Meter Drops Too Quickly November 19, 1979 HW-101 BULLETIN NO: SSB TRANSCEIVER...

  • Page 151: Ah.1.61.Hw-101-57: Relay Chatter In Vox Mode

     [[Shows the RF Generator ( set at 5.5mhz) connected to the Marker/Sweep Generator (set at 4.5 Mhz marker on and Lo Sweep), which is in turn connected to the O-scope. The Attenuator is connected to the Sweep Generator. ]] ...

  • Page 152: Ah.1.62.Hw-101-58: Receiver Oscillations

    Perform the suggestions in TEBs HW-101-31 and HW-101-41. If this doesn’t correct the problem, then install two 0.1 uF capacitors [PN 27-28] across R308. This will reduce pulse rise time and improve VOX operation. Note: In some older transceivers, it may be necessary to add a higher value capacitor;...

  • Page 153: Ah.1.65.Hw-101-61: Parasitic Oscillations

    supplying an RF gasket and metal inserts to replace the rear panel nylon inserts to correct an RF leakage problem from the back of the HW-101 during transmit. This has been generating numerous phone calls to Technical Consultation from customers wanting the modification parts; whether they have RF leakage problems or not.

  • Page 154: Ah.1.67.Hw-101-63: Vox Delay Too Short

    C331 .01 uF ceramic disk 21-16 capacitor C332 thru C336 470 pF mica capacitor 20-128 R341 thru R346 470 kilo Ohm, 1/2 watt 1-33 resistor Phase shift circuit board 85-2138-1 “F” connector (3 qty.) 432-734 ah.1.67. HW-101-63: VOX Delay Too Short AUGUST 12, 1980 HW-101 BULLETIN NO: SSB TRANSCEIVER...

  • Page 155: Ah.1.71.Hw-101-67: Cannot Zero S Meter With The Meter Zero Control

    ah.1.71. HW-101-67: Cannot Zero S Meter with the Meter Zero Control DECEMBER 11, 1980 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-67 Change: R104 from 47 ohm resistor to 75 ohm resistor [PN 6-750] R105 from 47 ohm resistor to 22 ohm resistor [PN 6-220] Make this change on an as-needed basis.

  • Page 156: Ah.1.75.Hw-101-71: The #266-1116 Switch Detent Breaks During Installation

    Remove and discard R326. Install a 0.005 uF capacitor [PN 21-27] between the underside foil of pin 1 of V15 and the end lug of the volume control (inside lug that is nearest R302 & 303). Install a 500 kilohm CW volume control [PN 10-149] with a fiber washer [PN 253- 34] as shown.

  • Page 157: Ah.1.78.Hw-101-74: Keys Continuously When Used With The Sa-5010 Memory Keyer

    ah.1.78. HW-101-74: Keys Continuously When Used With the SA-5010 Memory Keyer JANUARY 21, 1982 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-74 This may be caused by a defective 6EA8 tube [PN 411-124] at V15. To check for a defective tube, increase the volume to maximum on the HW-101, switch to CW mode, and listen for a 1-kilohertz tone.

  • Page 158: Ah.1.82.Hw-101-78: Tune Control Slips

    ah.1.82. HW-101-78: Tune Control Slips APRIL 29, 1983 HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-78 To prevent the loading shaft from slipping when the tune control is adjusted, install two nylon washers and a spring washer behind the loading shaft pulley onto the loading shaft.

  • Page 159: Ah.1.85.Hw-101-81: Preselector Capacitors Won't Take Solder

    ohm resistor to a 47 kilohm resistor [PN 6-473]. This will raise the VFO output by another 0.1 VRF. These power increases may make the difference between a unit that will meet transmitter power specs and one that will not. ah.1.85.

  • Page 160: Ah.1.89.Hw-101-85: Vox Activates When Mike Not Connected

    R6 AND R7 from a 33 kilohm, .5 watt resistor to a 33 kilohm 1 watt resistor [PN 6-333-1]. Also check the 100 kilohm resistor at R215 and the 22 kilohm resistor at R316 for signs of overheating. If necessary, replace them with 1 watt resistors: 100 kilohms [PN 6-104- 1] and 22 kilohms [PN 6-223-1].

  • Page 161: Ah.2.Sb-100 Service Bulletins

    ah.2. SB-100 Service Bulletins ah.2.1. SB-100-1: Diode Leakage in The SB-100, SB-101, HW-100 May 23, 1974 SB-100 Bulletin No:SSB Transceiver SB-100-1 The silicon diodes used in the SB100 & SB101 are standard power diodes rated at 500PIV & 750MA. For each condition described, the diodes should be replaced with an equal value to maintain proper operation.

  • Page 162: Ah.2.3.Sb-100-3: Sb & Hw Series Audio Preamplifier & Vox Circuit Trouble Shooting Guide

    8. Using an insulated screwdriver, adjust neutralizing capacitor for a MINIMUM indication on the VTVM. 9. Readjust the neutralizing capacitor for a minimum indication on theVTVM. 10. Turn the FUNCTION switch to the off position. 11. Discharge high voltage power supply capacitors. 12.

  • Page 163: Ah.2.4.Sb-100-4: Sb & Hw Series Instability And Corrective Information

    Pin 8 of V1 .1 - .3VAC Center Arm of VOX Sensitivity Control 5-15VAC Pin 7 of V17 5-10VAC Pin 6 of V17 40-50VAC Junction of C211-D201 40-50VAC Pin 9 of V12 9-15VAC By tracing the AC signal from stage to stage the point of trouble can be isolated & steps taken to correct it.
  • Page 164 6. Check the hardware for the side rails to be sure a good ground is being provided. 7. Be sure that all the ground clips on the coil cover are making good contact with the switch shields. 8. Check the soldering of the switch shields to the center pins of tube sockets V6, V7, V10 &...

  • Page 165: Ah.2.5.Sb-100-5: Oscillations Or Low Drive

    25. Check to be sure that the PA tune shaft turns the variable capacitor & is not slipping in the insulated coupling. ah.2.5. SB-100-5: Oscillations or Low Drive December 18,1974 SB-100 Bulletin No: SSB Transceiver SB-100-5 Loose boards cause sporadic self oscillations & unstable RF conditions, particularly at the high [15 &...

  • Page 166: Ah.2.9.Sb-100-9: Tuning Erratic

    + + + + Information not yet available + + + + ah.2.9. SB-100-9: Tuning Erratic February 22, 1978 SB-100 Bulletin No: SSB Transceiver SB-100-09 Some of the earlier LMOS can be opened up for service, such as cleaning the wiper contacts on the tuning cap when tuning becomes erratic.

  • Page 167: Ah.3.Sb-101 Service Bulletins

    ah.3. SB-101 Service Bulletins ah.3.1. SB-101-1D: Driver Oscillates on 40 Meters June 12, 1967 SB-101 Bulletin No:SSB Transceiver SB-101-1D Remove C-924 [.02 disc capacitor] from across 150K ohm resistor & delete from circuit. ah.3.2. SB-101-2D: Switch Action Improvement November 1, 1967 SB-101 Bulletin No:SSB Transceiver SB-101-2D...

  • Page 168: Ah.3.5.Sb-101-5D: Grounding Problems On Transceivers

    DELETE: (2) B21-31 (50) CAPACITOR, DISC .02 MFD Z5U : (2) B21-31 (49) " " " " "DELETE: (4) 85-131-1 (1) PC BOARD, RF DRIVER MIXER : (4) 85-131-1 (1) " " " " REMOVE: C-424 installed across R-401 NOTE: SBM-100-1 called for the installation of this capacitor on SB-100 units. This capacitor should now be removed.

  • Page 169: Ah.3.8.Sb-101-3: Sb & Hw Series Audio Amplifier & Vox Circuit Trouble Shooting Guide

    ah.3.8. SB-101-3: SB & HW Series Audio Amplifier & VOX Circuit Trouble Shooting Guide May 23, 1974 SB-101 Bulletin No: SSB Transceiver SB-101-3 It is assumed that the basic steps such as making DC voltage measurement, checking tubes & reviewing the soldering have been completed. The following information was compiled from the above transceivers in the 80M LSB position.

  • Page 170: Ah.3.9.Sb-101-4: Diode Leakage In The Sb-100, Sb-101, Hw-101

    If the frequency response of the audio stage is not within specifications check the values & installation of C1, C2, C3 & C9. A change in VOX delay after operating for a period of time can be caused by leakage in diode D201. The other possibility is a change in value of capacitor C213.
  • Page 171 5. Check all edges of the final enclosures for proper grounding to the main chassis. 6. Check the hardware for the side rails to be sure a good ground is being provided. 7. Be sure that all the ground clips on the coil cover are making good contact with the switch shields.

  • Page 172: Ah.3.11.Sb-101-6: Alternate Method Of Neutralizing The Final Amplifiers

    24. Check to be sure that the shafts do not touch each other in the insulated coupling, and that the set screws do not touch the PA shield. 25. Check to be sure that the PA tune shaft turns the variable capacitor & is not slipping in the insulated coupling.

  • Page 173: Ah.3.12.Sb-101-7: Oscillations Or Low Drive

    ah.3.12. SB-101-7: Oscillations or Low Drive December 18, 1974 SB-101 Bulletin No. SSB Transceiver SB-101-7 Loose boards cause sporadic self oscillations & unstable RF conditions, particularly at the high [15 & 10 meter] bands. The comb brackets which have been used are aluminum &...

  • Page 174: Ah.3.16.Sb-101-11: Transceiver Oscillates In Transmit With Mic Keyed

    ah.3.16. SB-101-11: Transceiver Oscillates in Transmit with Mic Keyed September 27, 1977 SB-101 Bulletin No: SSB Transceiver SB-101-11 + + + + Information not yet available + + + + ah.3.17. SB-101-12: Tuning Erratic February 22, 1978 SB-101 Bulletin No: SSB Transceiver SB-101-12 Some of the earlier LMOs can be opened up for service, such as cleaning the wiper contacts on the tuning cap when tuning becomes erratic.

  • Page 175: Ah.4.Sb-102 Service Bulletins

    ah.4. SB-102 Service Bulletins ah.4.1. SB-102-1: Meter Zeroing November 25, 1970 SB-102 Bulletin No.SSB Transceiver SB-102-1 Original 10-147 control tolerance not sufficient to allow zeroing in all units. This part is being re-specified to a closer tolerance. In the meantime, any field problems regarding zeroing of the meter can be corrected as follows: Change: R-107 from 100K Ohm to 82K Ohm [PN 1-159].

  • Page 176: Ah.4.4.Sb-102-4: Lmo Instability

    PAGE 119: Right Column #14 - will be deleted. ah.4.4. SB-102-4: LMO Instability March 30, 1973 SB-102 Bulletin No:SSB Transceiver SB-102-4 We have a possible cure for some of the LMO instability problems in the SB-102. The following should help eliminate any stress on the LMO chassis when installed on the main chassis.

  • Page 177: Ah.4.6.Sb-102-6: Sb & Hw Series Audio Preamplifier & Vox Circuit Trouble Shooting Guide

    ah.4.6. SB-102-6: SB & HW Series Audio Preamplifier & VOX Circuit Trouble Shooting Guide. May 23, 1974SB-102 Bulletin No:SSB Transceiver SB-102-6 It is assumed that the basic steps such as making DC voltage measurement, checking tubes & reviewing the soldering have been completed. The following information was compiled from the above transceivers in the 80M LSB position.

  • Page 178: Ah.4.7.Sb-102-7: Sb & Hw Series Instability & Corrective Information

    - A change in VOX delay after operating for a period of time can be caused by leakage in diode D201. The other possibility is a change in value of capacitor C213. Either component could experience a change in operation characteristics due to heat.

  • Page 179: Ah.4.8.Sb-102-8: Alternate Method Of Neutralizing The Final Amplifiers

    NOTE: This does not include a light bulb. Check for normal Het. Osc. test-point voltage. Check for proper LMO injection voltage 1.0-1.5 VRF. Check for a high AC ripple content in the LV-B+, HV-B+ and bias voltages from the power supply.

  • Page 180: Ah.4.9.Sb-102-9: Oscillations Or Low Drive

    NOTE: Take adequate steps to eliminate any possible contact with B+ or B+ shorts to chassis after disconnecting wire & resistor. ah.4.9. SB-102-9: Oscillations or Low Drive December 18, 1974 SB-102 Bulletin No:SSB Transceiver SB-102-9 Loose boards cause sporadic self oscillations & unstable RF conditions, particularly at the high [15 &...

  • Page 181: Ah.4.12.Sb-102-15: Poor Agc Action

    ah.4.12. SB-102-15: Poor AGC Action June 5, 1978 SB-102 Bulletin No:SSB Transceiver SB-102-15 Leakage in the 6HS6 tubes [PN 411-247] at V10 and/or V11 has been found to cause: Poor AGC action Fast S-meter decay Poor sensitivity when RF gain control is fully clockwise. This usually occurs after warm up of at least an hour.

  • Page 182: Ah.4.16.Sb-102-19: Relays Chatter In Vox Mode

    ah.4.16. SB-102-19: Relays Chatter in VOX Mode August 7, 1978 SB-102 Bulletin No:SSB Transceiver SB-102-19 This may occur when the VOX gain is in the near-full CW position with the MIC level advanced past the 12 o'clock position. Also, the unit will not return to receive when the operator stops talking.

  • Page 183: Ai)Using An Hw-101 As A 100-Watt Pa

    SB-102 into transmit mode as described in this article. When I was a young ham in 1977, I saved money to buy and build a Heathkit HW-101. The rig has served me well over the years, going in and out of storage as my interests and addresses changed, but it seemed destined to return to storage forever after I finished building the K2.

  • Page 184: Ai.1.The Basic Mod

    Therefore, strange though it may sound, the HW-101's final stage can be used as an amplifier by feeding an exciter signal into its receiver input. Testing reveals that this presents a reasonable load impedance to the K2, and about 1 watt of drive is required to bring the HW-101 to full output.

  • Page 185: Ai.2.The Enhanced Mod

    ai.2. The Enhanced Mod When the HW-101 switches to transmit, the receiver front end is disabled by applying a cutoff bias to the receive stages. It is (probably) important to avoid transmitting directly into the receiver front end when the receive circuits are active, that is, when the HW-101 is in the receive mode.
  • Page 186 and dip the Final Tune as usual. Once resonance is reached, advance the K2's Power control until no further increase in plate current is noticed, then back it off a tad. I found that full output power could be achieved on all 5 bands with between 1 and 2 watts of output from the K2.

  • Page 187: Aj)Tube Substitutes

    aj) Tube Substitutes Whenever possible, tubes should be replaced with the specified type. This table lists some possible substitutes if the original type is not available. Note: Tube types consisting solely of numbers may be ruggedized or industrial versions of the same tube. Tube Substitutes 6626, 6073...

  • Page 188: Ak)Tube Test Data

    ak) Tube Test Data Serial Number: __________________________ Date: ____________________________ TV-7 Tube Tester Setup Replacement Tests Functi Designation Type Rang Filament Bias Shunt Press Min Value Speec V1a (pentode) h Amp Catho 6EA8 V1b (triode) Follow Isolati 6AU6 Amplif Amplif 6AU6 Amplif 6AU6 Trans...
  • Page 189 TV-7 Tube Tester Setup Replacement Tests Functi Designation Type Rang Filament Bias Shunt Press Min Value Driver 6CL6 Final Amplif 6146 Final Amplif 6146 Amplif 6HS6 Recei 6HS6 Mixer V12a Recei (pentode) Mixer 6EA8 Relay V12b (triode) Amplif V13a (diode) V13b (diode) 6BN8 Produ...
  • Page 190 TV-7 Tube Tester Setup Replacement Tests Functi Designation Type Rang Filament Bias Shunt Press Min Value Tone V15a Oscill (pentode) ator 6EA8 Tone V15b (triode) Amplif Carrie V16a (triode) 12.6 Oscill 12AU7 ator V16b (triode) 12.6 V17a (triode) Amplif 12.6 12AT7 (ECC81) Calibr...

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Hw-101Sb-100Sb-101Sb-102Hw-100

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