200S problem

[play4zero]

Had my 200S at the techs and he said something about the sine waves not being too good on one side and that the amp is only putting out about 25 watts.  The output transformer is good, but he can't seem to identify the problem.   Any ideas?

[EdBass]

Yes, I have an idea...

Find a new tech.
Seriously, the 200S is about as straightforward and basic as it gets in a production MI amp, it's handwired, no complex PCB's, and schematics are plentiful.
However, there are several things that could be causing the rather vague symptoms you are describing and diagnosing a broken amp on the internet is a crap shoot at best.

Really; find a good tech locally and your life will probably be much easier.

[Ryan Phelps]

EdBass is absolutely correct. The 200S is really simple, but on-line diagnosis of the problem is dicey. You need to find a tech that knows how to use his eyes and ears, read a schematic and use a VOM to diagnose the amp. Oscilloscopes are great tools, but clearly this tech doesn't understand tube amps. Go to the thread on Sunn-friendly amp techs
( http://sunn.ampage.org/sdp/index.php/topic,3747.0.html ) and take your amp to one of them. If you are near Seattle I can fix it too.

Good Luck
Ryan

[play4zero]

That's what I thought.  Unfortunately, I'm in KC so no one on the list from here.  I have the name of another tech and I'll try him and then post the name of whoever is able to fix it reasonably.  I also wanted the impedance switched around and took out the links for thatand left them with the last guy and haven't found them again in the search function.  there was a great one with pictures, if memory serves.

[Soundmasterg]

I would be checking the phase inverter circuit to see how things look there, both with the power tubes in circuit and with them out of circuit. The waveform will look strange if the amp is clipping, but it should put out a good honest 60 watts RMS when everything is working correctly, and with clean sine waves. But yah, take it to a tech who has some hands on knowledge of these amps instead of a solid state history or a theoretical knowledge. They are simple amps to work on.

Greg