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Yamaha cr-820 Output transistor Mouser part numbers

Looks like someone has already scratch in the heatsink N -- NPN and P -- PNP..
MJ21193G --- PNP
MJ21194G --- NPN
May want to clean off the old heatsink compound and use some fresh compound on both sides of the mica insulators.
 
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avionic;

I will amend my shopping list to these two output transistors, as well as the TP721 (863-MJE15030G) that I picked up the part number from your earlier threads.

Thank you very much for your concise and patient advice.
 
The heatsink compound you mention, is that the same as dielectric grease that I can pick up at the auto store? Or is it something different.

Strike that - I see that it is different. I will pick some up at my computer parts store.
 
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Hello

Don't use grease from computer store . They only have computer grease not usable for HIFI use . Computer grease is conductive using it for your amplifier will cause drastic dammage
 
MiKokomojoe said:
The heatsink compound you mention, is that the same as dielectric grease that I can pick up at the auto store? Or is it something different.

Strike that - I see that it is different. I will pick some up at my computer parts store.
Click to expand...

clinic-audio said:
Computer grease is conductive using it for your amplifier will cause drastic dammage
Click to expand...
Patrice is right..
Use this...
https://www.mouser.com/ProductDetai...EpiMZZMsiS1%2BJOF5Pn3GMWa%2BnNI0cmHFvkwaV4XA=
 
Apply thinly and watch for the thermal compound getting on the threads of the mounting screws. First time I reinstalled the output transistors on my Yamaha CA-610II apparently got too much on the screw threads of one output transistor and a replacement driver transistor did not survive long. Lesson I never forgot took me a bit to figure out the scenario of what went wrong. One of my first repair projects.

Too much on the screw threads can leave the output transistor isolated from the power supply leaving the driver transistor to take on the load.
 
Time for an update!

I received my parts from Mouser.
I only installed the two new output transistors, and the unit works!
I have tested the tuner, Aux input, and phono inputs, and all seems well.
I was really feeling my oats, so I even read the manual on adjusting the amplifier board (p10) and made a slight adj to the right channel. Both are 8-9mv.
TR721 is now running around 100 degrees; about same as the others.

You can't believe how proud I am that I have faced my fear of electronics, and had a good result. Of course, I'm no Einstein;
I OWE IT ALL TO YOU GUYS! Thanks.

I am going to treat my pots with deoxit; is there anything else I should check before I button her up?
 
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