Discussion in 'Yamaha' started by mr.muddles, Aug 25, 2018.
Yes, the service manual from hifiengine.
This is good :
How do you want me to test the transistors ? with the right tool (not ohm meter . It will not tell you if the TR is leaking .....Diode meter may be used but it will tell you if the TR is shorted nothing else
out of circuit if you want to be sure : yes always
with a diode test ? not good enough for me
Do you have some new TR ?
I just have half an hour for you tonight (it is late here)
I don't have any new transistors...
I was waiting to put in my order but I guess the time is now.
I only have the diode test... some day I will get a transistor checker.
So I do anything else or wait for new transistors?
I rechecked this one and it looks good now...
I will get replacements for TR527-530.
@clinic-audio should I put one pair of good transistors back in the preamp and test it?
yes only on the working channel not on the other one (bad)
most important : stay in stereo do not swith to mono
I had 14 V from TP2 to TP3
I think something is wrong...
I turned it on again and i thought i heard a spark.... TR527 is getting scorching hot again... -39V
using the dim bulb tester... if i touch TR527 the light bulb dims and then glows according to when I touch it...
When I touch TR527 it makes like a small rice crispy sound... a small faint pop
but TP2 and TP3 is left channel no ?
YES ! for sure
I think that it is going complicate for you to refix this
send me a PM
I too just recently got a c2a with similar symptoms, right channel has 37V on testpoints and on stereo right ch has no output (luckily since it would've fried my speakers) and on mono both channels play. I've measured few transistors as of now and at least TR520 or 522 is open. I pulled both and mixed them up. Is it safe to power with these two removed?
It's probably best to start your own thread. This one's not really active anymore. I was unable to resolve my issues and sent it to be looked at by a professional.
I will update this thread when I've gotten it back and have news of what was wrong. If it can be repaired. (hopefully)
Ok, good luck getting yours fixed.
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