Cobra 29 LTD WX Classic Receive Problem

[skybolt58]

Hi, I have a 29, I was talking on it the other day and it lost Receive, it transmits and modulates great, PA works great! no meter movement on rec, no sound. what could be the problem,? someone told me to replace r 31 so I did, no help! the schematic showed a 47K ohm there, but it originally had a 4.7K ohm there? please ? thanks for any info, I am a disabled vet with limited income, and try to repair all my junk..

 

[222DBFL]

Have you tried using an external speaker?? Or I could be your mic as well. Open the bottom up and check the speaker connections to the board and speaker and check the wiring at the mic socket inside the radio. If that doesn't work or all is good try another mic if you have one. Good luck and hope you get it fixed. God bless.

 

[sonoma]

a couple things I would check would be D1 through d10 diodes and check the solder joints for cold solder at all the receive cans . also tr14 ,this would be a start for the receive area. since the meter is not moving for receive at all .

 

[skybolt58]

Have you tried using an external speaker?? Or I could be your mic as well. Open the bottom up and check the speaker connections to the board and speaker and check the wiring at the mic socket inside the radio. If that doesn't work or all is good try another mic if you have one. Good luck and hope you get it fixed. God bless.

There is no REC meter movement, and also Yes I tried ext sp. it rec with a cb on the same desk. very close?

 

[skybolt58]

a couple things I would check would be D1 through d10 diodes and check the solder joints for cold solder at all the receive cans . also tr14 ,this would be a start for the receive area. since the meter is not moving for receive at all .

Just to add, while I was talking , I noticed that the person I was talking to sort of went off frequency and then went weaker and weaker all within 5 min, then gone>?

 

[sonoma]

Just to add, while I was talking , I noticed that the person I was talking to sort of went off frequency and then went weaker and weaker all within 5 min, then gone>?

check for bad solder joints in the receive area and at the vco and pll and 10.240 crystal area to see if you have cold solder. since it is going in and out or fadding is a good sign of a bad solder joint.

 

[skybolt58]

check for bad solder joints in the receive area and at the vco and pll and 10.240 crystal area to see if you have cold solder. since it is going in and out or fadding is a good sign of a bad solder joint.

thanks for the help. I will check all the Solder. gonna take a bit, Bed time now!

 

[skybolt58]

cobra 29 ltd wx classic

I found the bad spot, it was on L7, resoldered it and all up and running again weeeeeee Thanks for all who gave me Ideas!

 

[sonoma]

I found the bad spot, it was on L7, resoldered it and all up and running again weeeeeee Thanks for all who gave me Ideas!

after you mentioned the fade out that sounded more like a bad solder joint. funny how they can work for years then all of a sudden just go bad.
glad you found it.