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Desktrac repeater audio weak

Posted: Thu Aug 12, 2004 6:51 pm
by SmilnDon
I have a Desktrac UHF repeater and lately the audio is very weak in repeat. If you hook a mic up to the front it transmits loud and clear.

However, if you try and use it you can barely hear the person on the other end and they can barely hear you.

It still receives, but the audio is really low. What could it be? Receiver desensitivity? I had it running through a celwave duplexer tuend to 462/467.650 Mhz. Even hooking it up to 2 different antennas it still was weak audio.

Posted: Thu Aug 12, 2004 8:08 pm
by 1motoman
As a radio out lives its intended service life, it gets old.

I would guess the capacators in the audio chain have dried up.

Posted: Thu Aug 12, 2004 10:56 pm
by Will
Don, try the disconnect/reconect on the rear and front connectors on both radios, that may help. There is also connectors on the interface/front pannel baord also.

Also if the audio is distorted it may be the 33uF cap on the input to the first audio filter stage on the Receiver's logic board gone bad.

Posted: Fri Aug 13, 2004 11:47 am
by jackhackett
Possibly the repeater deviation adjustment? Should be R17, on the front panel top right, try messing with that, might get lucky and just have a dirty pot.

Posted: Fri Aug 13, 2004 11:55 am
by SmilnDon
1motoman wrote:As a radio out lives its intended service life, it gets old.

I would guess the capacators in the audio chain have dried up.
I was thinking that might be the case. Ill try all the suggestions.

1motoman, would that be the audio capacitors in the recieve radio side?

Anyone have a Maxtrac with a bad PA and/or control head that I could use to replace the recieve side? Also, does it matter how many channel Maxtrac it is? I would assume that the important part is the logic board, correct? Then you could use the guts from any Maxtrac. Yes? No?

Posted: Fri Aug 13, 2004 12:17 pm
by Tony Soprano
I've seen troubles like these before, I think jackhackett has the right idea. The one I had this trouble with was stubborn, and I replaced the entire front panel interface board from a junk chassis. Worked fine after that.

Desktrac Weak Receive Audio

Posted: Tue Aug 17, 2004 1:09 pm
by SmilnDon
Well, I tried the R17 on the front board. Took the repeater off the air, then a few days later got some electronics cleaner from Radio Shack, sprayed it down, blew it out with low pressure air to dry it, then two days later put it back up and its now loud and clear. Not sure if it was just sitting around for a week not in use or cleaning the R17 Pot, but its back! Yay!

I did also reseat all the connectors on the receiver though too. Since I had it apart, I did everything that was suggested so I wouldnt have to keep opening it up. So Im not sure exactly what did it. I just know that it now works 100%.