Bias adjustment on Marshall 2195 100W Lead and Bass

[Timbo]

Thanks for your help so far, everyone. I’ll post some numbers tomorrow am.

[Timbo]

What is the voltage measured between the bases of TR12 and TR13?
How much can you vary it with RV1?

Hi Helmholtz, the voltage between the two bases is only 36mV. That value does not change over the full range of RV1.

[Timbo]

If the bias circuit is defective, you need to locate the part responsible by troubleshooting, not just swap parts.
(post #13)

Indeed, it is starting to look that way!

[Timbo]

T8 was short circuit across collector and emitter. Replaced that and now RV1 is working as it should. Set voltage across emitter resistors to 4.5mV. No sign of any crossover distortion now and it sounds cleaner.
Thanks again.