[TechAssist] Re: ctc186a no audio

Now we're talkin'.

Audio at the output jacks would indicate everything to the output IC is 
good, and overrule a software mute (eeprom problem).  With the mute 
transistor out, and no audio either channel, this leaves u1901 or its 
power supply, pin9, 26v, or leaky c1910 47uf.  U1901 is 215526/tda7263

For future use:
No tuner audio.
Do you have audio on the external inputs?  If yes, your problem is in here:

Wide band audio comes out of the T-chip at pin 3, looks like 1v pk noise 
at 5mS sweep.  Goes into u1600p11 (4vdc)

U1600p1 is data
U1600p2 is clock
U1600p15 is 8.8v Vcc
U1600p28 is Rt channel out
U1600p29 is Left channel out

Outputs are direct coupled to U1601 pins 3 and 5, left and right 
respectively.

U1601 is stereo mixer, outputs on pins 1 and 7, left and right respectively.
These feed back into U1001 pins 4 and 5, and are output again from pins 
60 and 59.

If no audio from external inputs or tuner, your problem is in here:

External audio goes into U1001 on pins 7 and 8.
Audio leaves U1001 on its final journey at pins 60 and 59 to U1901 pins 
5 and 1, outputs on 8 and 10.  Power supply on 9, 26v and mute is pin 3 low.


Wayne Vanaman
Omega Electronics
6904 W Fairfield Dr
Pensacola, Fl.  32506-3310

Wayne@xxxxxxxxxxxxxxxxxxxxx
WWW.PensacolaTVRepair.Com

850-456-5995 voice
850-458-6369 fax


D Trippel wrote:
>      Hello
> Service #   F20637ETFB1          cr4704 and r1908 are good as well    Thanks
> 
> 
>>Gads! There are a slew of them from 20 inchers to 36s!
>>Can we get a model number?
>>Better, a Service Number.
>>
>>Wayne Vanaman
>>Omega Electronics
>>6904 W Fairfield Dr
>>Pensacola, Fl.  32506-3310
>>
>>Wayne@xxxxxxxxxxxxxxxxxxxxx
>>WWW.PensacolaTVRepair.Com
>>
>>850-456-5995 voice
>>850-458-6369 fax
>>
>>
>>D Trippel wrote:
>> 
>>
>>
>>>Hello Everyone
>>>
>>>I am working on a ctc186a with no sound. The speakers are turned on in 
>>>customer menu. I removed Q1903 still no sound.I checked parameters in 
>>>set up. 20-00  22 -00 23-00  24-28  .What are the correct setting? Or do 
>>>I have a diffent problem. There is no audio present at the audio out put 
>>>jackes as well. I checked r1617 it is 100 ohm. Thanks!!
>>>
>>>Don Trippel
>>>Don's Electronics
>>>Rosthern,Sask
>>>Canada
>>>
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