JCM900 chips?

[drewl]

Before I go looking, maybe y'all can save me a little time.
I have a Marshall JCM900 with a bad opamp. It's one of the 5201's in the master volume circuit.
Does it cross to anything common and easy to find?
Thanks...I'll start looking now.

[Twist]

I think www.tubesandmore.com sells those.
Also you can find a datasheet under M5201.

[drewl]

Well luckily the 5201 chip was okay. I swapped it with the one that amplifies the reverb return but I still had the same problem.
The voltages in that preamp stage were all wrong, as a hunch I tried V2b's plate coupling cap which was bad and leaking dc voltage into the following 5201 amp/switching stage causing it to malfunction, so take note if you come across the same problem.