On the spectras, if you keep using the radio after the caps go bad, it can
damage the audio ic chip.
The popping is one of the symptoms as well as distorted audio.
Another thing I have seen is a tantalum chip cap that is the isolator cap
between the audio chip and the previous chip.
Just follow the audio-in line backwards from the audio chip to find it.
( am doing this from memory and not looking at a book or would give part
numbers)
The audio chip from mot last time I bought one was about $24.00 dealer price if
I remember right.
Hope this helps.
Happy Thanksgiving Everybody !!!
Mike
Specialized Communications
KB5FLX
----- Original Message -----
From: Tim Ahrens
To: Repeater-Builder@yahoogroups.com
Sent: Tuesday, November 24, 2009 10:32 PM
Subject: RE: [Repeater-Builder] Spectra Audio Popping after Capacitor
replacement
Hi David,
Is the Hear Clear board only on the 900 mhz spectras?
I was looking in my service manual, and it talks about
the board plugging into P501, but on my VHF spectras,
this plug is unpopulated..
As a side note, when I went to replace the capacitors,
I noticed that a fire ant had given it's life while spanning
a couple of pins on the audio output TDAxxx part. There
seemed to be some 'liquid ant residue' remaining, so perhaps
it damaged the audio amp. I guess I'll have to look at
the thing with the scope & see what's going on in comparison
to one that works 'correctly'.
Thanks!
Tim
