Randall RG200 G3 Low power

[reflection77ca2000@yahoo.ca]

Just repaired a randall RG200 Transformer. There were some voltages that had gone astray. Now amplifier is functioning for the first time in 6 months except that now power is quite low. It sounds clean as a whistle though.
The out put is 3 J162 and 3 J1058. What is the best start to determine my output problem?

[Enzo]

Isolate the problem. Power amp, preamp or speaker?

Have you tried a different speaker and different speaker wiring?

Is there an FX loop on this? or a preamp out and power amp in pair of jacks? Send the signal from the preamp out or the FX send to some other amp and speaker for a listen. Weak or strong? Likewise, plug a signal into the FX return or power amp in jack - weak or strong?

Got a schematic? Post it or link it.

Apply a signal and follow it through the stages to see where it diminishes.

[reflection77ca2000@yahoo.ca]

Thank you for tips.

[reflection77ca2000@yahoo.ca]

OK line out is nice. Ran it to recording interface. Full signal.

[reflection77ca2000@yahoo.ca]

Maybe it is the recently intoduced Omega-3 in my diet.
I suddenly have an urge an desire to learn about J162 and J1058.
How they work together and how to test them in the circuit.
So far I have found the J162 to all have -67VDC and the J1058 to have +67VDC.
What next?

[Enzo]

I doubt they are bad. They are just push pull transistors in the output. By all means learn about them, they are MOSFETs, but I would be surprised if they are causing your low output.

Did we inject a signal into the power amp itself?

Did we try a different 12AT7 tube? Are the tube heaters both glowing?

And apply signal and trace it through the stages.

[reflection77ca2000@yahoo.ca]

Tried a different tube, slightly stronger in strength. So I can inject say -10dbv signal and listen with small headphone with probe? Just follow path with schematic?

[Enzo]

Well I would normally use a scope, but without that a signal tracer is easily made with a cap in series with the input of some other amp. And for level only, even using a voltmeter set on AC volts will allow you to follow signal around.

[reflection77ca2000@yahoo.ca]

What cap would be good in series. Like a non polar 4.7 kind of idea?
Anyway the good news is that I am learning something. This amp was a basket case. I traced the initial problem back to the transformer which had leads touching internally got the amp back up and running with low output.
I was checking TR7 and was missing 375VDC. Followed it back to power supply and untimately, the transformer leads. Possible that all that shorting may have finished off transformer after hours of working with it semi funtional.
Now what?

[reflection77ca2000@yahoo.ca]

Baby steps. I found still more transformer workmanship issues had to add solder. Looks like 120V across QC7 and QC11 of power supply. Not making 375VDC though. Also seems like when I plug 375VDC in to power amp. Voltage drops significantly.