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Well done on your persistence! A great thread for anyone in future working on one of these i’m sure will be a valuable resource!

Imf tls-80mk2 here

I believe ksc1815 is preferred to ksc1845 in certain locations so best to check before replacing 2sc1313

Add the housing for the 2385/2500 to the list

Fantastic result!

T they should be same as other Japanese receivers from that range

Mouser.com

Ss47 - mje182g Sps439 - bc546 maybe mpsa42 also

Also another thought make sure meter board solder points aren’t touching the vu meter housing it’s very close there

Popping if it’s intermittent could be a bad solder joint or damaged track on one of the semiconductors? Are the outputs securely into the pin holders? I do notice the relay on my 250 gets warm too but haven’t had any issues.

They sound totally different, if you like the 771 keep it and look for a 881 if you feel the need to get more power however the tone is very sililar The 717 is a great amp just different to the 771, more modern later design and has a faster bottom end and darker treble response

Did you change the relay

What happens if you put the original transistor back in?

This is a great explanation whilst in most instances it doesn’t matter in circuit designs and situation it makes a difference

Even bi polar caps have a negative and positive perhaps this is causing a potential issue and might be good to restore to stock to isolate it

Ok thanks for clarifying if that’s the case then there’s another reason why it ran hotter than you expected did it run warmer than before the heat could be normal

The bias should be set at 33mv so 100mv is too high check out my thread on my repair it explains how to do bias measuring mv over the emitter resistors as opposed to the method in the manual If you set it 100ma as per the manual then you did it correctly did you measure Milivolts or miliamps?

Any possibility the rca input is damaged for that side?

If you haven’t already also change all the vd1212 diode and fuse resistors as preventative maintenance and to rule out unreliable components

Could also be bad filter caps or power supply sounds like a cap discharging at switch off but the relay is supposed to suppress that noise check your relay too.

Did you replace the safety cap also?

Can you check the voltages on f2630? I had issues on this board recently if you can’t measure the voltages remove the board and test the transistors and diodes and look for any shorted /open components

Maybe start a new thread so we can work through it with you but bias should be 33mv not 100mv

Also check if you have the correct fuse it varies pending on which market you are in the rear panel will tell you which one is correct

You can use bd139/bd140 I’ve only encountered a small handful of instances of where the flying saucer transistors have failed, more often the 2sc871 in these amps are an issue