Cobra 29 ltd no recieve

[joeglo]

I am new to cb component repair so bear with me. I have a Cobra 29 ltd 2007 manuf. date. I bought this cb as non working so I could learn repair. It powers on, has 3.5 watt transmit with good modulation, no receive meter swing, no sound. I have done a IRF 520 power mod, and replaced the YD1022 audio IC since there was no TX modulation (carrier only) and no audio when I received the radio. I now have 3.5 watt carrier and good modulation but still no receive and no sound. Any direction as to where to look would be appreciated. Thanks joeglo

[TheCBDoctor]

I am new to cb component repair so bear with me. I have a Cobra 29 ltd 2007 manuf. date. I bought this cb as non working so I could learn repair. It powers on, has 3.5 watt transmit with good modulation, no receive meter swing, no sound. I have done a IRF 520 power mod, and replaced the YD1022 audio IC since there was no TX modulation (carrier only) and no audio when I received the radio. I now have 3.5 watt carrier and good modulation but still no receive and no sound. Any direction as to where to look would be appreciated. Thanks joeglo

Hi joeglo,

Go to pin 10 on the YD-1022. Using chassis ground not the case ground. See if you are getting half the supply voltage of !3 volts. If you are reading anything other than 6 volts or so, then the audio chip is no go. If it is bad it will show 13 volts or zero volts. If you have TA 7222AP do the same thing except on Pin 9. Check the solder connections on the Rx IC mixer near the VCO. It is covered with bee's wax It is not uncommon to have a bad solder connection in this area. I have run into this problem 100s of times over the years.

Just resolder the 9 Pin mixer from the bottom. Watch out for D-13 and D16 the surface mounted Varactor diodes. You don't want these to fall of. Make sure the caps are discharged by disconnecting the power supply and turning ON the radio.

Good luck

[joeglo]

Thanks for the reply. I found a bad solder point, repaired it and all is well. joeglo

[KG4KGW]

Thanks for the reply. I found a bad solder point, repaired it and all is well. joeglo

Did your solder repair fix your RX issues? How did you find it? I'm sure others here would like to know too

[joeglo]

Sorry about the long time for a reply. I found the audio IC was bad and found a new YD1022 . Replaced it and all is well with the world. Thanks for all the help. joeglo

[baconater4749]

Hey Bud,,where did you find the YD1022 Audio Power Amp, I need a few and I cannot find them any place,I am
baconater4749...Thank you in advance.Mark

[MDYoungblood]

@baconater4749,
That thread is over 9 years old, poster might not even be a member anymore.

3's

Greg