Cobra 2000GTL VERY low receive volume

[Adamf]

Hi all, I have a Cobra 2000GTL that hit receives but receive is BARELY audible.I had a bad 11.325mhz xtal, I replaced it carefully and tried the radio and now receive is VERY VERY low ( was full volume the other day). It's not the crystal, I put back the old one and receive volume is still low. It's not the squelch, not the RF Gain, not the speaker, not the speaker jack 1 or 2 or phones, all are low. Can anyone help? I am pretty handy and not afraid to try. Thanks for any help, Adam

 

[LeapFrog]

Hi all, I have a Cobra 2000GTL that hit receives but receive is BARELY audible.I had a bad 11.325mhz xtal, I replaced it carefully and tried the radio and now receive is VERY VERY low ( was full volume the other day). It's not the crystal, I put back the old one and receive volume is still low. It's not the squelch, not the RF Gain, not the speaker, not the speaker jack 1 or 2 or phones, all are low. Can anyone help? I am pretty handy and not afraid to try. Thanks for any help, Adam

I am still a newbie, but I would say the radio is slightly off frequency now from the repair you have made. It may need just a slight adjustment (alignment) with the proper test equipment or perhaps it is an issue with your soldering (Did you remove any leftover flux, and check for solder bridges)?

How did you determine the crystal had gone bad?

 

[Adamf]

I am still a newbie, but I would say the radio is slightly off frequency now from the repair you have made. It may need just a slight adjustment (alignment) with the proper test equipment or perhaps it is an issue with your soldering (Did you remove any leftover flux, and check for solder bridges)?

How did you determine the crystal had gone bad?

Simply, the frequency was low by about 6khz in all modes, replaced it and now frequency is perfect. Adam

 

[LeapFrog]

Do you (or know someome) have the gear to perform a receiver alignment? Transmist frequency is not the same as for the receiver, due to how the transceiver mixes the if stages, the frequency counter may not reflect the rx alignment. Having never worked on a 2000GTL and speaking in generalities here take my comments with a grain of salt.
I would re-align the radio, at least the receive section.
If you find there is still low rx audio look for failed components and other potential problems (not so obvious) issues like coax, antenna SWR, mic wiring coming loose.

I hope any of that can help. 73 -Leap

 

[Adamf]

Do you (or know someome) have the gear to perform a receiver alignment? Transmist frequency is not the same as for the receiver, due to how the transceiver mixes the if stages, the frequency counter may not reflect the rx alignment. Having never worked on a 2000GTL and speaking in generalities here take my comments with a grain of salt.
I would re-align the radio, at least the receive section.
If you find there is still low rx audio look for failed components and other potential problems (not so obvious) issues like coax, antenna SWR, mic wiring coming loose.

I hope any of that can help. 73 -Leap

Hi, thanks, it's not an alignment issue. I am looking for someone familiar with the Cobra 2000GTL who can tell me what it may be. Thanks, ADam

 

[Robb]

Did you check out the PA function to see if it isn't an audio chip problem - yet?

 

[Adamf]

Did you check out the PA function to see if it isn't an audio chip problem - yet?

No, I am not too bright, I made the veteran mistake, I forgot it needs the mic to receive, it's fine. Ouch!! Thanks, Adam

 

[LeapFrog]

No, I am not too bright, I made the veteran mistake, I forgot it needs the mic to receive, it's fine. Ouch!! Thanks, Adam

I made that mistake once or twice, talk about face palm city!
Only two pins are used for rx to produce audio on many Cobras.
When the mic is plugged in the connection is made through the wiring at the p.t.t. switch, you can see the two pins used on most 4 pin Uniden/Cobra radios.
The other pins are left unconnected for the jumper plug,
I used an old microphone end I had laying around.
[photo="medium"]4087[/photo]
I keep it on the bench ready for any 4 Pin Uniden/Cobra I'm going to test.
Problem solved rx audio on the bench with no microphone, you could also make a 5 pin plug.

 

[222DBFL]

Hey it helps to plug the mic in LOL! Glad you got the "issue" sorted. Now go sit in the corner for 10 min.
I know I have done this a few times. Don't know a or others here, but I am sure that most have done this at least once or twice in their lifetime messing with radios!! Especially when you get tired!!