Realistic STA-90: small signal transistors to replace

[rkgren1]

I have started a recap on my Realistic STA-90.

I am compiling a list of caps but I want to replace potentially problematic transistors as well.

The list from the manual is below.

Which should I buy replacement for ?

2SC839
2SC710C
2SC710D
2SC536
2SA733
2SA733P
2SA733Q
2SA841
2SC1681
2SC1509
2SC1539
2SC1567
2SA794
2SC1403
2SB511

 

[ryuuoh]

Do you have hiss? if not, I'd pass on the transistors.

 

[SoundOfSound]

Replace the differential pairs with matched pairs.

 

[drdave3]

Which ones are differential pairs?

 

[kwayde]

Which ones are differential pairs?

TR601a and TR602a

TR601b and TR602b

Replace with matched ksa992's.

 

[tarior]

If they aren't acting up, I wouldn't replace any of them.

 

[drdave3]

If they aren't acting up, I wouldn't replace any of them.

Can any of you tell me the best way to remove this audio amp board? It looks like I could take the front panel off or slip the board out backwards. Any suggestions?

 

[TomSc]

From what I can find on Google, you don't need to take the whole board out. You can remove the faceplate and get to everything. It looks like there is another plate behind it that can be unbolted and swung out of the way for access.

 

[drdave3]

Yes! Thank you. And thanks for the photo!

 

[Skip L]

From what I can find on Google, you don't need to take the whole board out. You can remove the faceplate and get to everything. It looks like there is another plate behind it that can be unbolted and swung out of the way for access.

View attachment 3481746

Anyway of getting to the caps just under the dial indicator without having to pull and restring the tuning rope? Not real comfortable with the idea of having to restring the dial.

 

[TomSc]

I've never worked on one of these, but you might be able to tape off or zip tie the string onto the pulleys and swing the faceplate off to the side.