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Yamaha CR-2020 Pre - C Transistor Matching

SharkBait07

New Member
What are the matching pairs that need to be changed out on the A and B boards if one (or more) transistor fails?

I found a bad TR502 (2sc1213a - NPN) on board A and a bad TR504 (2sc1213a - NPN) on board B. I understand the transistors need to be replaced in PNP/NPN pairs. With that being said, does this look correct:

Board A
TR502 (2sc1213a - NPN) tested bad
TR501(2sa674a - PNP) replace to match TR502

Board B
TR504(2sc1213a - NPN) tested bad
TR505(2sa674a - PNP) replace to match TR504

On the schematic it looks like board A is for the left channel and B is for the right. Should I also match any changes made done on board A match changes on board B for matched audio output?

So in the end I am looking at replacing both TR502 matching sets and TR504 matching sets on boards A and B. That is to match NPN/PNP transistors and match L/R audio quality. Is this correct or something else?

Are these the substitutes to use for the "best" audio quality?
2SC1213A ---> KSC2383 (O)
2SA673A ---> KSA1013 (Y)
 
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