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Yamaha T-85 no sound output

L

longgun708

Member
I have a T-85 that has no sound output. It lights up and lets me get AM and FM channels and keeps the channels indicated after powering down. I have tested in circuit all of the transistors and don't see any that seem suspect. I also checked the capacitors ( with a fluke 187 esr) and all seem to have reasonable values. I also checked the power supply and it seems OK too. I am working with a schematic that I got from hi fi engine and its a little cloudy at times but works ok. I have read and reread the posts on here that covered this topic and I didn't see anything that seemed similar to the issue that I am up against. I do not have a scope or a signal generator. Just the Fluke.
I did find a lower than indicated voltage on Q 263 by 6 volts but can't see a reason why.

Can anyone offer any insight? I would appreciate any help. The other posts that I read seemed to find a bad capacitor but all of the values seemed reasonable. What would a bad cap reading look like?

I like doing this and am just trying to get it working again but I am an admitted beginner.
Thank you
 
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Find IC210 measure the +/- Vcc on pins 1 , 9 & 5.. This is the audio output op-amp.. Should be in the 12v ballpark.

What voltages are you seeing on Q266 ?
 
:thumbsup:

Q290,292,293 and 294 emitter voltages ?

As well as Q281 emitter voltage.
 
Have you and tried a different IC cable between the Tuner out, both High level and Normal and your pre-amp ?

What are you using for a pre-amp ?
 
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