CTC197: no audio

[Andy Cuffe]

I have two RCA CTC197 sets with the complaint of no audio. The first
one seemed fine, but I resoldered the audio and tuner areas just to be
safe. It came back with the same complaint. I've had both sets
running all day for a week with no trouble (both tuner and A/V
inputs). Are there any known problems that can cause intermittent
loss of audio on these sets?

I found this on Google which sounds like my problem. Is there a fix
for this problem?

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Here is what you need to try first. Unplug the tv for 1/2 and hour
then plug it
in and reprogram it completely. If the sound comes back on it is not
realy a
tv defect per Thomson. The Tv-guide plus is receiving a code from the
tv
stations when they go to commercial which is causing it to lock out
the audio,
unplugging the tv will reinitialize the audio. Yes it is a nuisance,
but
several tv stations have just started sending out codes on the same
info line as
the tv-guide plus.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Andy Cuffe
[email protected]

 

[Art]

Andy: Thomson TTT 00-001
CTC 195/197/203
No or weak audio via tuner mode, line inputs not affected.
U16201 # 49 should read Apx 3.9 VDC (u12101 in 203 chassis)
If this ckt is not working that voltage will aproack 7 VDC
C12304 off # 3 of L12303 near Pin # 1 of that ic
CR12301 off # 1 of L12303.
Both surface mount components.
hope this helps.

 

[RonKZ650]

I posted the same basic question about a month ago concerning the CTC203 with
no responses, but I've also had several CTC197s. Either the speakers are shut
off, or no problem found on probably 20 in just the last year. I haven't
figured anything out.
Ron

 

[Jason D.]

I have two RCA CTC197 sets with the complaint of no audio. The first
one seemed fine, but I resoldered the audio and tuner areas just to be
safe. It came back with the same complaint. I've had both sets
running all day for a week with no trouble (both tuner and A/V
inputs). Are there any known problems that can cause intermittent
loss of audio on these sets?

I found this on Google which sounds like my problem. Is there a fix
for this problem?

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Here is what you need to try first. Unplug the tv for 1/2 and hour
then plug it
in and reprogram it completely. If the sound comes back on it is not
realy a
tv defect per Thomson. The Tv-guide plus is receiving a code from the
tv
stations when they go to commercial which is causing it to lock out
the audio,
unplugging the tv will reinitialize the audio. Yes it is a nuisance,
but
several tv stations have just started sending out codes on the same
info line as
the tv-guide plus.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Andy Cuffe
[email protected]

This is true, also make sure the mute circuit isn't prematurely muting
audio.

Cheers,

Wizard

 

[Andy Cuffe]

This is true, also make sure the mute circuit isn't prematurely muting
audio.

Cheers,

Wizard

How do I determine if this is the problem? I have yet to see either
set act up.
Andy Cuffe
[email protected]

 

[David]

Do these have the early versions of the Gemstar 4 module? If so
certain codes certain tv stations send out turns off the audio, tv has
to be unplugged to fix. There has been a class action lawsuit against
Thomson over this one.

That chassis also will turn off the audio outputs if it sees any kind
of dc detect on the speaker line. Make sure it is not borderline.

Plus the myriad of problems on the clock and data can cause this
symptom. Especially conductive glue under certain surface mount
components on the clock and data lines.

This type of problem almost guarantees the need for a 4 channel or
more digital storage oscilloscope. Thomson's ctc195 and later
chassis' was the reason we had to upgrade our equipment.

David

 

[Art]

Thomson TTT-00-001
CTC-195/197/203
No Audio in tuner modes, Line inputs may work ok
RE: 195/197 Check # 49 of U16201 should be apx 3.9 VDC, 203 # 49 of U12101.
Not functioning voltage aproaches 7 VDC
RE: 195/197 check C12304, 203 C12309 for open, # 3 of L12303 near # 1 of
U16201 / U12101 in 203 chassis
Also CR12301 # 1 of L12303 All in FM detector ckt.
BTW no antennea or cable to the set audio noise may be present, once
antennea or cable connected, may mute or go to a very low level.