SPILSBURY SBX-11A Service Manual

Ssb portable radio telephone

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SPILSBURY

COMMUNICATIONS

1495 Franklin Street

Vancouver, B.C. V5L 5B6

Tel: (604) 254-6411

Fax: (604) 254-2080

Telex: 04-55482

SERVICE MANUAL

SBX-11A

SSB Portable

Radio Telephone

65-5014

September, 1997

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Page 1 SPILSBURY COMMUNICATIONS 1495 Franklin Street Vancouver, B.C. V5L 5B6 Tel: (604) 254-6411 Fax: (604) 254-2080 Telex: 04-55482 SERVICE MANUAL SBX-11A SSB Portable Radio Telephone 65-5014 September, 1997...
Page 2: Table Of Contents
TABLE OF CONTENTS DESCRIPTION General Description Specifications OPERATING INSTRUCTIONS BATTERIES General Selection Recharging and Replacement ANTENNAS Figure Fixed Tuned Figure Tuneable Whip CIRCUIT DESCRIPTION Oscillators Receiver Transmitter Metering Miscellaneous Circuitry TUNING & ALIGNMENT Crystal Information Channel Filter Information Main Chassis Removal Tuning to Channel Frequency Basic Tuning MAINTENANCE &...
Page 3 AC or DC source. The SBX-11A has been designed for the utmost in simplicity of operation and care. All controls, metre, speaker and microphone are accommodated on the front panel. A cover with carrying handle is supplied to protect the entire front panel when the set is not being operated or when in transit.
Page 4 SPECIFICATIONS General Mode of Operation: Single sideband - suppressed carrier (3A3J) USB standard LSB available on special order. Number of Channels: Four. Crossband Operation: Available on all channels. Temperature Range: -30 to +50 Degrees C. Frequency Stability: +/-100 Hz. Frequency Range: 1.6 - 8 MHz.
Page 5 SPECIFICATIONS (Cont’d). AF Response: +/- 3 dB 400 - 2500 Hz. RF Output Impedance: 50 Ohm nominal. Output Protection: No damage shorted or open antenna. ALC: Limits power to 10 W PEP maximum. Receiver Sensitivity: 0.5 uV for 12 dB SINAD. Selectivity: 2.1 kHz bandwidth at 6 dB down.
Page 6: Operating Instructions
SSB operation. To avoid unnecessary battery drain keep the transmitter ‘ON’ only as long as is absolutely necessary for antenna tuning. CAUTION Always turn the power off at the volume control before replacing the cover of the SBX-11A for transportation. Failure to do so will discharge the batteries.
Page 7: Selection
Nine size ‘D’ regular flashlight cells connected in series for a nominal value of 12 Volts, supply power to the SBX-11A. These cells are inserted in groups of three into plastic tubes which fit into the battery box on the bottom of the set. The battery box unlatches from the set with two pull down catches.
Page 8 Battery Table The following sets of batteries are recommended: Battery Life No. of SCL # Eveready Burgess Mallory Hrs. Recharges Nickel Cad. AC-19K CD-10 Alkaline AC-19I AL-2 MN-1300 NOTE: The SCL number listed above is a complete battery set. When ordering by manufacturer’s number, nine are required.
Page 9: Recharging And Replacement
When to recharge or replace batteries. To check for weak batteries, push the TUNE button for five seconds and check the meter indication immediately upon releasing the microphone button. SBX-11A Meter Scale: Green If the meter falls in section: A: Replace batteries if non-rechargeable or recharge if rechargeable.
Page 10 (MHz) of channel preferably, the antenna height (H) = length (L) 6. TO OPERATE: Set up antenna and connect leads to the SBX-11A, one to each binding post. Connect ground assembly if needed. Antenna is now ready for operation - no...
Page 11 A counterpoise may be needed if the ground is poor. Some notes for tuneable antennas (i.e., Spilsbury Communications Ltd. STA-210 Series) are: 1. Connect wire from resonator unit to antenna (ANT) binding post. Connect wire from ground stake to ground (GND) binding post.
Page 12: Oscillators
SECTION V - CIRCUIT DESCRIPTION Refer to SBX-11A schematic while reading the following description. For location of P.C. board components see the component layout diagram of the printed circuit board. OSCILLATORS The receiver channel oscillator is Q104. Its frequency is varied by the CLARIFIER C501.
Page 13: Transmitter
Thermistor R150 stabilizes the bias over the temperature range of -30 Deg. C to +50 Deg. The output load impedance is nominally 50 Ohms but the SBX-11A will operate into 25 to 100 Ohms with very little reduction of power with no reloading.
Page 14: Metering
If the supply voltage exceeds about 18 V the zener diode D1 will conduct and blow the fuse F1. (This should not occur with any of the power options offered for the SBX-11A). If the supply polarity is reversed the zener diode will conduct in the forward direction and blow...
Page 15: Crystal Information
High Frequency Oscillator (H.F.O.) Transmitter and Receiver Crystals One each required per channel. (Two total of same frequency) Spilsbury Communications Part No. 85-222, frequency is calculated as follows: 1. Determine Assigned Frequency as per D.O.C. document. 2. Determine Suppressed Carrier Frequency by subtracting: a) 1.5 kHz from the Assigned Frequency for Land Equipment...
Page 16: Channel Filter Information
CHANNEL FILTER INFORMATION Frequency Colour ‘RX’ ‘TX’ ‘PA’ Range Code Filter Filter Filter 1.6 - 2.0 MHz White 01-214 01-219 01-206] 2.0 - 2.82 Black 01-215 01-220 01-207 2.82 - 4.0 Brown 01-216 01-221 01-208 4.0 - 5.66 01-217 01-222 01-209 5.66 - 8.0 Orange...
Page 17: Tuning To Channel Frequency
Tuning to Channel Frequencies Minimum test equipment necessary Standard signal generator with a calibrated low impedance output (50 Ohms or less) A frequency counter with accuracy of 1 part in 10(6) or preferably 10(7) Hz with an input sensitivity of .01 Volts at 1 MegOhm. A 50 Ohm non-reactive dummy load resistor.
Page 18 Tuning to Channel Frequencies (Cont’d) Adjustment of Crystal Frequencies Adjust the speech clarifier control so the arrow points directly up (toward top of front panel). Turn the power on and measure the frequency at the RX H.F.O. test jack (on main printed circuit board).
Page 19 Tuning to Channel Frequencies (Cont’d) As the sensitivity increases always adjust the signal input level to maintain about 1 Volt across the speaker. When nearing maximum sensitivity the volume control may have to be adjusted somewhat to reduce the level across the speaker, thereby avoiding overloading of the audio amplifier.
Page 20 (Cont’d) Supply Voltage Output Current .27A .28A .29A .31A NOTE: These are theoretical values that assume a measurement accuracy of at least 3%. As this is unnecessary the 12V figure is rounded up to 0.3A in the rest of the text. Do not attempt to tune the transmitter with batteries or a power supply on which the output voltage varies with the amount of load.
Page 21: Basic Tuning
Basic Tuning and Alignment NOTE: These adjustments should only be required with component replacement or after long periods of use. Steps should be done in sequence shown. Minimum Test Equipment Necessary Test equipment specified for tuning to channel frequencies. An audio oscillator. A milliammeter (V.O.M.) Receiver LFO (C138).
Page 22 (b) Cont’d (iii) Apply 4 to 6 mV RMS 1000 Hz audio signal at MIC jack to result in exactly 45 mV RMS at AUD jack with P.T.T. switch pressed. (iv) Adjust TX filter, tank coil and output loading capacitor for maximum RF output current into the dummy load as per (c), (d) and (e) of Transmitter tuning to channel frequencies but disregard detuning instructions.
Page 23: Trouble Shooting
SECTION VII - MAINTENANCE & REPAIR TROUBLE-SHOOTING If the SBX-11A has been working satisfactorily and suddenly fails, check the following items in the order given before proceeding with any further investigation: Are all switches and controls in the correct position?
Page 24: Stage Gain Charts
12. Check the main supply voltages (see schematic). 13. If the performance degradation has been gradual, go through all tuning operations step by step. 14. If the set has failed completely or if the above checks do not reveal the trouble, stage gain checks will be required, see the transmitter and receiver stage gain charts.
Page 25: Replacement Of Pa
STAGE GAIN CHARTS RX Stage Gain - Volume Maximum Clockwise - Connect a signal generator to the test point through a 0.01 uF capacitor (except at RX ANT and AUD connect direct) - Frequency of signal generator adjusted to result in 1000 Hz audio output - Input levels should be adjusted for 2.4 V RMS across the speaker or 30 Ohm load 250 TEST POINT INPUT LEVEL RMS...
Page 26 FIGURE 3 MODULE LPA2 - TOP VIEW Removal of Defective PA (See Figure 3 Above) Unsolder wires at junction T105/R149 b) Unsolder three wires of T106 and clear holes on PCB Unsolder two wires of T105 and one of L108 and clear holes d) Remove screw holding C127 support bracket.
Page 27 Module Adjustment PA Bias R153. Measure supply current while pushing the PTT switch but without modulation. Turn R153 fully counter clockwise. Advance R153 for increase of about 5 mA (4 mA to 7 mA). b) Operate transmitter into dummy lead following section VI D5 of the manual. If antenna current falls within 220 to 360 mA RF, retune as described in manual.
Page 28 SECTION VIII - PARTS LIST CHASSIS ASSEMBLY REF. DESCRIPTION PART NO. DIODE Zener 1W 18V 1N4746A FASTENERS Strikes 45-177 Catch (Swivel) for lid 45-176 Catch (Riveted) for battery box 45-175 Bail Wire (for Lid Catch) 45-182 FREQ. CHART 4 Ch. Blank 59-082 Plastic Cover 57-1138...
Page 29 CHASSIS ASSEMBLY (Cont’d) SOCKETS 3 Pin DIN (Battery 22-113 Antenna Red 13749/001 Ground Black 30-051 SWITCHES (Part of R1) — Tune/Operate 4PDT Switch Assy. 36-088 Bezel for S2 36-093 Button for SW 36-156 Switch for SW 36-204...
Page 30 SECTION VIII - PARTS LIST BATTERY BOX REF. DESCRIPTION PART NO. CONTACT Kit (Two pieces) 62-169 Rubber 21-105 PLUG 3 Pin DIN 34-062 TUBES Plastic (three required) 21-046...
Page 31 SECTION VIII - PARTS LIST TX-RX MODULE HTR2 REF. DESCRIPTION PART NO. CAPACITORS C101 Ceramic Disc 0.01uF 10% 100V 24-361 C102 Ceramic Disc 0.01uF 10% 100V 24-361 C103 Metalized Foil 0.1uF 10% 250V 24-159 C104 Ceramic Disc 0.001uF 10% 100V 24-044 C105 Ceramic Disc 0.01uF 10% 100V...
Page 32 PARTS LIST (Cont’d). DESCRIPTION PART NO. CAPACITORS C137 Mica DM10 390pF 5% 500V 15-106 C138 Variable 2 - 18.5pF 17-037 C139 Mica DM10 12pF 5% 500V 15-180 C140 Mica DM10 100pF 5% 500V 15-040 C141 Metalized Foil 0.1uF 10% 250V 24-159 C142 Mica DM10 330pF 5% 100V...
Page 33 PARTS LIST (Cont’d) DESCRIPTION PART NO. CHOKES L101 Iron Core 2.5 mH 02-013 L102 Iron Core 2.5 mH 02-013 L103 Iron Core 2.5 mH 02-013 L104 Iron Core 2.5 mH 02-013 L105 Iron Core 2.5 mH 02-013 L106 Iron Core 2.5 mH 02-013 L107 Iron Core 2.5 mH...
Page 34 PARTS LIST (Cont’d) DESCRIPTION PART NO. INTEGRATED CIRCUITS U101 HF Differential Amp CA3053 70-201 U102 HF Differential Amp CA3053 70-201 U103 DC Differential Amp CA3028B 70-205 U104 Audio Amp LM386 70-211 U105 Wideband Amp 1/2W CA3020A 70-206 Heatsink for U105 50-298 U106 8V Regulator 7808, TO-220 pkg.
Page 35 PARTS LIST (Cont’d) DESCRIPTION PART NO. RESISTORS R127 Carbon Film 10 Ohm 5% 14-022 R128 Carbon Film 1M 5% 14-019 R129 Carbon Film 180 Ohm 5% 14-037 R130 Carbon Film 1/4W 10K 5% 14-008 R131 Carbon Film 1M 5% 14-019 R132 Carbon Film 180 Ohm 5% 14-037...
Page 36 PARTS LIST (Cont’d) DESCRIPTION PART NO. RESISTORS R162 Carbon Film 470K 5% 14-017 R163 Carbon Film 2.2M 5% 14-068 R164 Carbon Film 2.7K 5% 14-063 R165 Carbon Film 22K 5% 14-010 R166 Carbon Film 15K 5% 14-054 R167 Carbon Film 470K 5% 14-017 R168 Carbon Film 1/4W 10K 5%...
Page 37 SECTION VIII - PARTS LIST CHANNEL SELECTOR FCU7 DESCRIPTION PART NO. CAPACITORS C501 Air Variable 1.4-14pF (Clarifier) 18-031 *C502 Film Variable 2-18.5pF 17-037 *C503 Film Variable 2-18.5pF 17-037 C504 Mica Variable 390-1400pF 17-031 PLATE Coil and Crystal Grounding 57-1346 SWITCH S501 Sections A to E 40-163...
Page 38 50-233 Grommet, PVC, 5/16” 51-013 Guide Plate for Centre Case 57-1197 Rail Centre 57-1679 Decal ‘Spilsbury C.L.’ Logo 59-018 Decal ‘SBX-11A Serial No.’ 59-119 Booklet (plasticized) Operating Instructions 59-120 Label, Battery Instructions 59-144 Tubing, Teflon #20 21-017 Pad, Neoprene 1/8” x 3/4”...
Page 39 Tubing, Teflon #10 21-037 Tape, Double-sided Adhesive 21-103 Socket, Transistor 4 Pin PA 22-085 Socket, 8 Pin Dil. 22-193 Label, Coil 59-145 Decal ‘SBX-11A’ 59-239 Slug-Iron, RX/TX Coils 00-098 Slug-Iron, PA Coil 00-105 Button, Black for 36-088 Switch 36-156 Microphone Assembly 32-026...
Page 40 GENERAL CONDITIONS OF SALE Communications DEFINITIONS DAMAGES OR LOSS IN TRANSIT "Company" means Spilsbury Communications, a division of Racal Canada The Company accepts no liability for loss or damage in transit. Inc. "Customer" means the other contracting party. "Products" means the FORWARDING INSTRUCTIONS goods and services which form the subject of the quote.