CED Digest Vol. 5 No. 1

CED Digest Vol. 5 No. 1 • 1/8/2000
Date: Wed, 5 Jan 2000 13:18:04 -0800
To: digest@cedmagic.com
From: Tom Howe <ceds@teleport.com>
Subject: RE: where to find out of production I.C.s

>I own a Zentih VP2000 machine that has not been working for about 2 years.
>The sound no longer works, but the picture plays fine.  I took it to a local
>electronics repair shop where I am fairly good friends with the repairer and
>he said that one of the I.C. chips controling the audio had gone bad.  He
>said that the chip wasn't in any of his catalogs.  Does anybody know a
>source where these or suitable replacements are available?

This sounds like a failure of the Audio FM Demodulator IC, which is one of
the more common chips to fail in the RCA F/G players and clones like the
Zenith VP2000. Failure of this chip results in complete loss of audio on
mono players or loss of one channel of audio on stereo players, depending
on which of the two chips in the player has failed. RCA's stock no. for
this chip is 149035 and they also gave it a generic industry stock number
of CA3215E. A comparison of the circuit diagrams in the Hitachi, Toshiba,
and RCA service manuals indicates that those players using a 16-pin Audio
FM Demodulator IC all contain the same chip. Some of the companies listed
on the CED Player Parts Sources page (try Fox-International first) may
still have the part available:



http://www.cedmagic.com/home/ced-parts-links.html

Although the IC is generally the most likely culprit, it's also important
to test the components attached to the IC to verify that the chip itself
has failed and not one of the peripheral components. The above audio
demodulator IC contains a Voltage Controlled Oscillator that is set via an
external variable capacitor. If this setting is off the VCO may fail to
function properly.

--Tom Howe
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