Cobra 29LX/GTL/ST/LTD Classic
LESCOMM Expa Kit
Cobra 29 & like radio's
including the Dwight D and Cobra 1000GTL
Solder the L29-3’s Power wire (loose yellow wire from the switch center terminal) to +8 VDC located at J13 along the right of the circuit board close to TR23.
Solder the L29-3’s BLACK wire to circuit board ground. Keep lead short.
Lift the leg of C87 (C79) towards L22 (L19). Solder the L29-3’s GREEN wire to lifted leg of capacitor C87 (C79). KEEP THIS WIRE AS SHORT AS POSSIBLE! C87 (C79) is located along side of IC-2 (TA7310P).
The L-29-3 kit switch can be installed anywhere on the radio. The wires are electrical and do not carry RF or capacitance that will change the frequency. Install the L29-3 PCBoard using the enclosed bracket on the side close to the channel selector. Be sure to mount it upright so the adjustments can be had easily.
Turn the unit on, and check all channels for operation. Adjust the VCO coil L19 (L20) if any of the higher or lower frequencies do not operate properly. Older 29’s may require replacement of D13 (D14) with an MV1404 or similar varactor diode to cover the entire range.
If the LOW band does not work, try soldering a 18-22pf disc capacitor from the junction of the GREEN wire and C87 (C79) to ground.
Put the channel selector on channel 20, and the kit selector switch to the CENTER/CB channel position. Adjust VC2 for 27.205 mhz. Next switch to the HIGH position. Adjust VC3 for 27.655 mhz. Next select LOW band and adjust VC1 for 26.755 mhz.
Switch back and forth between LOW band and HIGH band and adjust L17 (L17), L20 (L24), and L21 (L25) to balance output power evenly. Adjust L2 and L3 for best all band receive.
Return to the Center/CB channel position, and check for proper operation.
Adjust VR4 for maximum modulation. DO NOT CUT D11 !!!! Add a 1k ohm resistor in parallel with Diode D8 for more forward swing. Adjust L12, L13 and L14 to balance power across bands.
WARNING; IGNORE THE WIRE COLORS IN THE PHOTO'S. THIS IS A PROTOTYPE AND NOT A PRODUCTION WIRING HARNESS.
|Lo Bnd||CB||Hi Bnd|
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All Intellectual Property, as defined below, owned by or which is otherwise the property of LesComm or its respective suppliers relating to the LesComm kits, including but not limited to, accessories, parts, or software relating there to (the“Expa Kit System”), is proprietary to LesComm and protected under federal laws, state laws, and international treaty provisions. Intellectual Property includes, but is not limited to, inventions (patentable or unpatentable), patents, trade secrets, copyrights, software, computer programs, and related documentation and other works of authorship. You may not infringe or otherwise violate the rights secured by the Intellectual Property. Moreover, you agree that you will not (and will not attempt to) modify, prepare derivative works of, reverse engineer, decompile, disassemble, or otherwise attempt to create source code from the software. No title to or ownership in the Intellectual Property is transferred to you. All applicable rights of the Intellectual Property shall remain with LesComm and its suppliers.
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