Yamaha A-1 Repair and restore: beyond Deoxit

i dont see any componenets with discoloration or signs of burn. could the it be the output trans itself? it was real hot.
 
At this point I have no idea.Do you know how to check transistors ?
 
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could the it be the output trans itself ? it was real hot.

No ! if it is really hot , that mean that this TR is good but his bias is not correct at all
If you don't know how to test a TR it's gone be very difficult to help you from here
You can't say that a TR is bad if you are looking for any discoloration or signs of burn . A TR can be dead without any external sign .
I will post a picture from my notes .
This will help you to do the right things
 
I can't see the emitter resistors being bad without shorted outputs ...
 
I can't see the emitter resistors being bad without shorted outputs ...


This was an issue on one of my A-1's I couldn't adjust off set and low volume and distortion. it was the emitter resistors on that channel. I cant remember if it was one or both .

Nashou
 
three of them measure correctly. one of them is only O.L.

i had to measure them from under the board from their solder joints.

thanks for all the info about transistors guys. i read on them and i think im good to take them out and measure them. i was gonna do that tomorrow buyt now im thinking maybe i should replace this resistor first.
 
three of them measure correctly. one of them is only O.L.

i had to measure them from under the board from their solder joints.

thanks for all the info about transistors guys. i read on them and i think im good to take them out and measure them. i was gonna do that tomorrow buyt now im thinking maybe i should replace this resistor first.
Start with the outputs in the right channel.One or both of them may be shorted. Then replace the bad resistor.
 
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