uhf maxtrac receive audio distortion

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FCM
New User
Posts: 25
Joined: Fri Oct 18, 2013 12:17 pm

uhf maxtrac receive audio distortion

Post by FCM »

I am having an issue with distorted receive audio on my uhf maxtrac. Transmit audio is perfect. How can I correct this? Thanks greatly

Frank
Satelite
Posts: 672
Joined: Sat Aug 12, 2006 10:43 am

Re: uhf maxtrac receive audio distortion

Post by Satelite »

Hello:
The first thing id check is that the interconnect pins that make contact for the rf bd and logic bd are clean and not dirty as this can cause issues.
But usually it affects the transmit freq also but could still be the culprit.
Second id check the rx oscillator crystal Y52 on schematics if you have them which is a 44.645mhz crystal and is used only for rx and is not used in the tx section of radio.
The tx oscillator crystal for tx only is Y151 and is a 14.4 MHz cystal and normaly has a sticker on or near the crystal with a series of compensation numbers to be entered in radio if replaced.
The rx Y52 44.645 MHz in your case if replaced does not need anything entered into radios program just replaced but should be checked and radio tuned.
These crystals are on the rf bd and y52 is normaly hot glued to the bd as a support ect and normaly the only one glued from my experience so you should be able to locate it rather quickly from the glue
Id also check to make sure the radios speaker isn't blown causing a bad rx audio too - never know.
Try a good known front if you have one or plug in a rear speaker and listen ect.
If the rx crystal y52 44.645 MHz is going bad but can still hear then if you have a service monitor send the rx freq higher lower in freq and see if you can clear it up by sending another freq which then indicates a bad crystal in need of replacement.
Id also make sure the freq you are receiving was transmitted properly just to eliminate another possibility.
If the transmitted freq is distorted then the radio receiving it is going give it to you distorted so make sure its the rx and not a tx issue.
Good Luck
Satelite
Will
Posts: 6823
Joined: Tue Sep 04, 2001 4:00 pm

Re: uhf maxtrac receive audio distortion

Post by Will »

Did the OP check the speaker first?
Satelite
Posts: 672
Joined: Sat Aug 12, 2006 10:43 am

Re: uhf maxtrac receive audio distortion

Post by Satelite »

Hello:
I didn't say check the speaker first which I admit should be the first to check my oops.
I did mention it aprox 11 and 12 lines in on my posts.
Satelite
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