• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
  • Retevis is giving away Radios for the New Year and Every Member is Eligible. Click Here to see the details!

Cobra 29 LTD classic no transmit audio and motor boat noise on receiver audio


cb radio stuff - Page under construction

REPAIR TIPS:
29 GTL:
1. "Motorboating": Locate C242(.001)on pin 5 of TA7222 audio ic and move to pin 4 of ic.
2. Weak mic gain: Some raios have a 2SC372 mic amp. Replace with a 2SC945.
3. Receive on adjacent channel: Bad solder joint to C131 (next to 10.240 crystal).
29 LTD:
1. OVERMOD: Check D11
2. PLL dead, no TX or RX: Shorted C112
3. No TX/RX with Channel LED lit on RX and then goes out when keyed: Bad /shorted C119.
29 LTD Classic:
1. OVERMOD: Check D11. Missaligned VR4.
2. Internittent audio/modulation: Bad solder joints on pins 1&2 or 2&3 of audio ic.
3. TUNE UP TIPS: L11 is the TVI trap. DO NOT adjust!!! Stretching L12 gets moe output. L14 peak is about a turn or two up from factory original setting.
 

dxChat
Help Users
  • No one is chatting at the moment.