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Summary of Contents for NORCAL 2N2/XX
- Page 1 NORCAL 2N2/XX V1.2 Assembly Manual Copyright 2008/2009 by Jim Kortge, K8IQY and NORCAL...
- Page 2 A common assembly manual is used for all 2N2/XX rigs, therefore, no parts values are given in this manual, only part designators. This assembly manual is used with the band specific Bill of Material (BOM) and schematic diagram to identify the part values being installed.
- Page 3 expecting that the section will fix itself. It will not and the remainder of the build will be compromised. Please fix any and all problems as they occur! PCB Preparation Assemble the four 1-inch hex screws and 1-inch hex nuts to the four corners of the PCB. The screws go on the bottom side and the nuts on the top side.
- Page 4 - Figure 2 - Test - Apply 12 volts to the board. With a DVM or VOM, measure that more than 11.7 volts appears at the junction of D18 and C87. Your Measurements/Observations - ______________________________________________ ____________________________________________________________________________ Receive Active Power Decoupler Install transistor Q21 Install resistor R96 Install capacitor C38 matching the polarity markings on the capacitor case with those on the...
- Page 5 - Figure 3 - Test – Apply 12 volts to the board. Measure with a DVM or VOM that 11.5 volts (or more) appears at the left center pad where transformer T3 will be installed. Your Measurements/Observations - ______________________________________________ ____________________________________________________________________________ Receive Main Audio Amplifier Install transformer T3;...
- Page 6 Install volume control R80 (marked A10K) to the pads marked “VOLUME” using discarded leads from previously installed components as shown in the next figure. - Figure 4 - Install the SPKR jack, using the rear terminals, to the pads marked “SPKR” using discarded leads from previously installed components as was done above.
- Page 7 60 Hz hum should be heard coming from the speaker or headphones. Your Measurements/Observations - ______________________________________________ ____________________________________________________________________________ Receive/Transmit Keying Install the PN2907A PNP transistor at Q8 Install resistors R17 and R18 Install capacitors C14, C20 and C21 Your PCB should look like that shown in the next figure. - Figure 6 - Test –...
- Page 8 Your Measurements/Observations - ______________________________________________ ____________________________________________________________________________ Receive Mute Install the J176 JFET at Q7 Install diodes D2, D3, and D4. Note cathode ends (bar) so they are installed correctly. The anode of D3 and the cathode of D2 should be the non-grounded ends. Install the two test points provided for the R14 location, then install R14.
- Page 9 Test – Connect a speaker or headphones to the “SPKR” jack. Apply power to the board. Advance the volume control to maximum. Touch the top (ungrounded end) of diode D2; 60 Hz hum should be heard coming from the speaker or headphones. Rotate volume control R80 counter clock wise (CCW) to verify the hum level changes.
- Page 10 - Figure 8 - Test – Connect a speaker or headphones to the “SPKR” jack. Apply power to the board. Touch the pad on the minus end of tantalum capacitor C30 or the lower pad for L10. The hum volume should be louder than it was before this stage was added.
- Page 11 bag paper) over the crystal leads before soldering it to the PCB or leave a small space between the case and the PCB. This will keep the crystal case from shorting out PCB traces. Ground the crystal case with a short piece of wire to the provided adjacent ground pad. Your PCB should look like that shown in the next figure.
- Page 12 Install resistor R25. Install capacitors C25 and C31. Install molded inductor L10. Your PCB should look like that shown in the next figure. - Figure 10 - Test – Connect a speaker or headphones to the “SPKR” jack. Apply power to the board. Measure the mixer drive at the top of resistor R28.
- Page 13 Install capacitor pairs C37/C114, C34/C35, and C39/C115. Some of these capacitors may not be used at the IF frequency employed in your rig. Unused capacitors are shown on the schematic with a value of 0 pF. Install crystals X6 and X7. Place a spacer (made from brown bag paper) over the crystal leads before soldering it to the PCB or leave a small space between the case and the PCB.
- Page 14 Receive IF Amplifier Wind and install transformers T10 and T11. Each time a wire passes through the center of the toroid, it is counted as 1-turn. Install the MPSH10 transistors at Q12 and Q13. These devices look similar to several of the other plastic encased transistors.
- Page 15 Your Measurements/Observations - ______________________________________________ ____________________________________________________________________________ Receive Main Crystal Filter Install capacitor pairs C36/C111, C53/C56, C55/C113, C54/C57 and C52/C112. Some of these capacitors may not be used at the IF frequency employed in your rig. Unused capacitors are shown on the schematic with a value of 0 pF. Install crystals X1, X2, X3, and X4.
- Page 16 Your Measurements/Observations - ______________________________________________ ____________________________________________________________________________ Receive Post-Mixer Amplifier Wind and install transformers T4 and T9. T4 can be wound with either a pair of wires twisted together at 8-10 turns per inch and then wound on the core, or with the pair of wires wound in parallel.
- Page 17 - Figure 16 - Test - Connect a speaker or headphones to the “SPKR” jack. Apply power to the board. Connect an antenna to the upper-right pad of T4 or the pin 2 pad of where mixer M2 will be installed.
- Page 18 Install Q9 Install diodes D8, D9 and D10. Note cathode ends (bar) on D8 and D9 so they are installed correctly. D10 (a MV1662) looks like a transistor with only two leads and has no markings on it, just colored bands. Install resistors R52, R55, R56, R58, R59 and R60.
- Page 19 Install capacitors C42, C43, C62, C63, C64, C65, C66 and C74. Your PCB should look like that shown in the next figure. - Figure 19 - Test – Apply power to the PCB. Connect an RF probe or oscilloscope to the top of resistor R60. The RF probe should show an output level of approximately 0.16 volts.
- Page 20 displayed frequency will change with the rotation of R54, the tuning potentiometer. The high frequency end of the VFO tuning range is set by trim capacitor TC6 and the low frequency end by trim resistor R78. Adding in the RIT circuitry (in a later step) will change the tuning range and span of the VFO.
- Page 21 The RF probe should show an output level of approximately 0.15 volts. On an oscilloscope, the waveform should approximately match that shown in the next figure. - Figure 22 - Your Measurements/Observations - ______________________________________________ ____________________________________________________________________________ VFO Driver Wind transformer T5. Put the 16-turn primary (use red wire, not green wire as shown) and the 3-turn secondary (use green wire, not red as shown) windings on the T37-61 dull gray core with green dot, as shown in the next figure.
- Page 22 - Figure 24 - Install trim capacitor TC7. Install transistor Q16. Install resistors R39, R40, R41, R63, and R64. Install capacitors C78, C80, and C83. Your PCB should look like that shown in the next figure. - Figure 25 -...
- Page 23 Test – Temporarily connect a 51 Ohm resistor from the top of resistor R40 to ground. This resistor supplies a load for the VFO driver stage. Apply power to the PCB. Connect an RF probe or oscilloscope to the top of resistor R40. Peak the driver tuned circuit by rotating TC7 while watching the output level.
- Page 24 - Figure 27 - Test – Connect a speaker or headphones to the “SPKR” jack. Apply power to the PCB. Connect an RF probe or oscilloscope to the top of resistor R39. The RF probe should show an output level of approximately 0.25 volts. On the oscilloscope, the waveform should approximately match that shown in the next figure.
- Page 25 Connect an antenna to the top of resistor R66. Band noise and maybe a station can be heard. Adjust LO trim capacitor TC9 until the received band noise sounds the loudest and is at approximately 1 KHz. This isn't a critical adjustment at this time, just use your ears and let them be your guide.
- Page 26 - Figure 30 - Test – Connect a speaker or headphones to the “SPKR” jack. Apply power to the PCB. Connect an antenna through a 0.1uF capacitor to the upper pad where trim capacitor TC5 will be mounted. The band noise and stations heard should be louder than in the previous step due to the gain of this stage.
- Page 27 - Figure 31 - Test – Connect a speaker or headphones to the “SPKR” jack. Apply power to the PCB. Connect an antenna to the right pad where inductor L15 will be mounted. Alternately peak trim capacitors TC4 and TC5 until the band noise is the loudest. Only stations in the band should now be heard.
- Page 28 Install RF gain control R77 to the pads marked “RF Gain” using discarded leads from previously installed components Install capacitors C93 and C94. Your PCB should look like that shown in the next figure. - Figure 32 - Test – Connect a speaker or headphones to the “SPKR” jack. Apply power to the PCB. Connect an antenna to the lower pad where capacitor C95 will be mounted.
- Page 29 Your PCB should look like that shown in the next figure. - Figure 33 - Test – Connect a speaker or headphones to the “SPKR” jack. Apply power to the PCB. Connect an antenna to the lower pad where capacitor C95 will be mounted. Adjust R53 in both directions to verify the receiver tuning changes approximately 3 KHz up and down in frequency from the center detent position.
- Page 30 Install crystal X8; it will be the last one marked LO or XX. Place a spacer over the crystal leads before soldering it to the PCB. Ground the crystal case with a short piece of wire to the provided adjacent ground pad. Your PCB should look like that shown in the next figure.
- Page 31 Your Measurements/Observations - ______________________________________________ ____________________________________________________________________________ Transmit Main Mixer Install mixer M3. Before soldering all of the leads, make sure it it oriented correctly. A dot on the part and on the PCB denote the location of Pin 1. Install resistor R79. Your PCB should look like that shown in the next figure.
- Page 32 - Figure 37 - Connect an RF probe or oscilloscope to the top of resistor R79. The RF probe should show an output level of approximately 0.13 volts. On the oscilloscope, the waveform should approximately match that shown in the next figure. - Figure 38 - Adjust trim capacitor TC10 so that a cw tone can be heard from the receive strip.
- Page 33 Install resistors R86, R88, R89, R90, R91, R92, R93, and R94 Install trim potentiometer R87. Install capacitors C104, C106, C108, C109, and C110. Your PCB should look like that shown in the next figure. - Figure 39 - Test – Connect a speaker or headphones to the “SPKR” jack. Apply power to the PCB. Connect an RF probe or oscilloscope to the top pad of capacitor C103.
- Page 34 - Figure 40 - Your Measurements/Observations - ______________________________________________ ____________________________________________________________________________ Transmit Driver Amplifier Wind and install transformer T2. Install inductor L17. Install the 2N2219A transistor at Q2. Make sure that the bottom of the case is not tight to the PCB; space it up about 1/32nd of an inch. Install diodes D1 and D17.
- Page 35 - Figure 41 - Test – Connect a speaker or headphones to the “SPKR” jack. Apply power to the PCB. Connect an RF probe or oscilloscope to the top of resistor R81. Adjust trim resistor R87 to the middle of its travel.
- Page 36 Wind and install transformer T1. This transformer can be wound with either a pair of wires twisted together at 8-10 turns per inch and then wound on the core, or with the pair of wires wound in parallel. Either method will yield a suitable transformer. An example of each method was shown earlier in this manual.
- Page 37 previously installed components. The center of the BNC is wired to the “ANT” pad and the BNC ground to the “GND” pad. Your PCB should look like that shown in the next figure. - Figure 44 - Test – Attach a TO-220 style heat sink (or fabricate something similar) to final transistor Q25 as shown in the next figure.
- Page 38 Final Adjustments Now that the construction of your 2N2/XX PCB is complete, we can go back and do some final tune- up work to optimize the performance of the rig. We'll do it once here and again after the rig is installed in the case.
- Page 39 This procedure will optimize the receive sensitivity. With the receiver operating, apply a mid-band signal to the antenna connector using a signal generator (the NORCAL S1-S9 generator is recommended) set for 50 uV or less. As an alternate, attach an antenna and find a moderately strong signal.
- Page 40 Repeat the process for all of the pads that still have wires soldered to them until the board is free of wires and all holes are open. Your PCB should look like that shown in the next figure. (Ignore the fact that the Key pad holes still contain solder –...
- Page 41 - Figure 48 - TUNE (R54) - Cut 7 inch pieces of wire in colors Red, White, and Green. Strip 1/8 inch of insulation from each end and carefully tin. Solder the Red wire to the TUNE left pad, the White wire to the TUNE center pad, and the Green wire to the TUNE right pad.
- Page 42 - Figure 50 - SPKR (Speaker) - Cut 4 inch pieces of wire in colors White and Green. Strip 1/8 inch of insulation from each end and carefully tin. Solder the White wire to the SPKR left pad and the Green wire to the SPKR right pad.
- Page 43 - Figure 52 - PWR (+12/GND) - Cut 4 1/2 inch pieces of wire in colors Red and Black. Strip 1/8 inch of insulation from each end and carefully tin. Solder the Red wire to the PWR left pad and the Black wire to the PWR right pad as viewed from the closest PCB edge.
- Page 44 - Figure 54 - KEY (Key/Gnd) - Cut 2 inch pieces of wire in colors White and Black. Strip 1/8 inch of insulation from each end and carefully tin. Solder the Black wire to the KEY left pad and the White wire to the KEY right pad as viewed from the closest PCB edge.
- Page 45 2N2/XX rig. The front and rear panels contain all of the controls and connectors for the rig. Pem nuts are used to hold the PCB in the bottom shell and the front and rear panels to the bottom shell.
- Page 46 - Figure 59 - - Figure 60 - Using 2-56 X 5/16 flat head screws, #2 internal tooth lock washers, and 2-56 hex nuts, secure the tab part of the latch assembly to each side of the top shell. The tab goes on the outside and with the protrusion on the tab extending beyond the top shell edge as shown in the detailed photo.
- Page 47 With the latch components installed on the bottom and top shell pieces, place the top on the bottom and test the latches to assure they are working properly. The next photo shows how the case will look if the latches are installed correctly. - Figure 63 - Put the completed case aside for now.
- Page 48 - Figure 64 - Install Volume control potentiometer R80 (marked A10K) into the front panel from the back side, put on the washer, and then the hex nut. Tighten the control finger tight, as it needs to be able to rotate for ease of wiring later on. Repeat the above process with RF Gain control potentiometer R77 (marked A1K) Repeat the above process with RIT control potentiometer R53 (marked B1K) Install the 10-turn Tuning potentiometer R54 by putting the internal tooth lock washer on the...
- Page 49 control potentiometer should be rotated so that the wires reach it equally. Use the photographs as a reference in soldering the correctly colored wire to each potentiometer terminal. - Figure 67 - Next, solder the wires from the RF Gain pads to the RF Gain control potentiometer. Use the photograph as a reference in soldering the correctly colored wire to each potentiometer terminal.
- Page 50 Next, solder the wires from the RIT pads to the RIT control potentiometer. Use the photograph as a reference in soldering the correctly colored wire to each potentiometer terminal. - Figure 70 - With all of the wire sets correctly soldered to their respective potentiometers, the PCB-Front Panel assembly should look like the next photo.
- Page 51 - Figure 72 - Installing the PCB and Front Panel into Case Bottom Shell The next several steps will result in the PCB being mounted to the bottom case shell and the front panel being screwed into place on the front of the bottom case shell. Begin by removing all of the standoffs from the four corners of the PCB Using four 4-40 X 5/16 inch pan head screws, #4 internal tooth lock washers, and 1/8 X 3/16 inch spacers, mount the PCB to the bottom of the case.
- Page 52 - Figure 73 - Using four 4-40 X 1/4 inch flat head screws, mount the front panel to the bottom case shell. When the front panel is in place, rotate the potentiometers to optimize the layout of the wiring going to them. Then, tighten the nuts that hold the potentiometers so that they are snug. Additional cable lacing can be done at this point to hold the front panel wiring in place.
- Page 53 Install a BNC connector in the hole marked "Antenna". To install this connector, push the connector through the panel hole, place the wire lug over the back of the connector, put on the internal tooth lock washer, and follow this with the hex nut. Tighten the assembly with the wire lug pointing to the left when viewed from the back of the panel.
- Page 54 - Figure 78 - Following the details shown in the next photograph, solder the green and white wires coming from the "SPKR" pads to the "Speaker" stereo connector. The white wire is soldered to the left lug and the green wire to the right lug as viewed from the front. Next, solder the black and white wires coming from the "Key"...
- Page 55 - Figure 79 - Screw the rear panel to the case using 4-40 X 1/4 inch flat head screws. As the panel is being moved into position, route the wires so they are not close to components that have RF signals on them, such as coils or trimmers, as shown in the next photo.
- Page 56 Your 2N2/XX should look like the one in this last photo! - Figure 81 - Congratulation on the successful built of your NORCAL 2N2/XX. We hope you have enjoyed the building experience, will use the rig often, and enjoy it for many years.
- Page 57 Make sure you are using the correct schematic for the band you are building. There are significant part value differences among the three bands, therefore, you must use the correct schematic to successfully complete your 2N2/XX rig. 2N2/XX Features All discrete component, through-hole (except mixers) design.
- Page 58 The above chart shows the nominal VFO tuning ranges and IF frequencies for each band. However, the IF filter passband center in the 2N2/XX rigs actually fall just a bit higher than the IF frequencies shown, typically 500 to 600 Hz higher. What that means is that the VFO frequencies shown may have to be increased by a small amount to achieve the correct band operating frequencies as shown in the chart.
- Page 59 Primary Secondary...
- Page 66 2N2/XX Miscellaneous Information Toroid Cores Red core = T37-2 (Powdered Iron) Yellow core = T37-6 (Powdered Iron) White core (Used for VFO Inductor) = T50-7 (Powdered Iron) Shiny gray core = FT37-43 (Ferrite) Dull gray core (marked with green dot) = FT37-61 (Ferrite)