Adjusting output bias on Sherwood early receivers (S-7200) - Claude version?

[CCook]

I have read available AK posts on the subject, but I do not completely understand the answers. Likely my new-ness to solid state repairs.
Past has been primarily tube audio.

In any case, the manual procedures for the 7100 and 7200 either require a bench full of test gear, or an overly simplistic version with a watt meter.

I *think* the answer is to balance the current at the output transistor emitters for 10-15ma each. As calculated from the voltage drop on those emitter resistors (0.47 ohms). Would give 20-30ma total bias to outputs. Not sure what the exact target value should be.

I have a good Tektronics scope and a decent BK audio generator, so can view the cross over point. From what I read, the visual accuracy is not so great, is that true?

Of course, AI knows all, except when it doesn't. So I asked Claude for instructions to adjust bias for my Sherwood S-7200 based on web searchs and the downloaded service manual. Attached is the response

I would appreciate more experience readers out there to comment on this, and/or offer suggestions.

Thanks in advance.

 

[Dave1027]

That AI response sounds about right. It states 10-15 mV across the emitter resisters with a DMM. This guy sounds like he has experience setting it to 12 mV. https://audiokarma.org/forums/threa...ing-hot-sherwood-s-7200.1032853/post-16470889

You could use your scope to verify the crossover distortion is absent.

 

[CCook]

Thank you! That referenced post escaped my search.
I think it answers my questions.