Pro 2055 No audio

dbestfirefighter · #1 (**permalink**) 10-27-2009, 09:22 AM

Was unaware of the problems that this scanner was riddled with until i started searching for a possible fix for my problem. I have no audio at all with the sql wide open and the volume set at different levels, I can tune to a WX broadcast and see that I am getting a signal on the display but no audio. I have tried the ext speaker connection on the back as well, but still was unable to get any audio out... Any suggestions? Schematics?

gmclam · #2 (**permalink**) 10-27-2009, 02:10 PM

When you press a key do you hear a "beep"??? If so that pretty much means you have a bad volume potentiometer.

If you do not hear the beep, that tells me the problem is in the audio amplifier and possibly the external speaker jack. Since you tried an external speaker, that tends to rule out the jack, but not absolutely.

Ya know I've got a LOT of PRO-9x scanners here (the '97 is the same as the '2055) and I have not had all these problems (knock on wood). I don't know if there are some bad production runs or what.

dbestfirefighter · #3 (**permalink**) 10-27-2009, 04:25 PM

I will check it out shortly. Thanks

dbestfirefighter · #4 (**permalink**) 10-28-2009, 08:43 AM

As it turns out the keypad did beep. I turned the volume up all the way and was able to hear faint audio coming from the internal speaker, guess it was little noisy during the first round of trouble shooting. My guess is the audio amp circuit is this in an IC?

gmclam · #5 (**permalink**) 10-28-2009, 12:44 PM

Here's the deal, the audio from the beep goes from the CPU directly to the audio amplifier. Audio from the receiver goes through the volume potentiometer. It looks like you have a bad potentiometer. It is a common problem.

Yes the audio amplifier is "just an IC". LOL. So what? Most portable devices use ICs for audio amplifiers these days including cell phones and low end car radios. ICs are reliable as long as you don't abuse them. And since you're hearing a beep, yours is working.