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I shouldn't worry too much about voltages at the percussion board to start with, a fault here would only affect the percussion voices.

Pin 8 on the power amp board is signal input to the amplifier. Somewhere in the service manual there will be a set of conditions, (Something like U/M drawbar tab down, certain drawbars pulled out and particular key or keys played). If all is well playing the organ as specified for the test should give a signal at this point which can be observed on an oscilloscope. Note that the voltage is specified as peak to peak, which can only be measured on a 'scope, a meter reading RMS AC volts will read something less than half the P~P voltage. Pin 6 is return from the reverb tabs, there will only be signal here with reverb tabs down, and notes being played on the organ. Pin 19 is output to the speaker system, again, there will only be an AC signal voltage here if the organ is being played. There should never be a significant DC voltage here. Pin 2 on the power amp is DC power to part of the amplifier. Nominally +15 volts, I wouldn't worry if it isn't exactly +15.

I'm struggling a bit here, I no longer have the library of paper manuals that I used when I was working. I only have some downloaded scans which seem to be missing a lot of the useful text.

Hi Chris - I've started to check different voltages of 2 of the boards.? I started looking at the Percussion board.?

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At pin 10 with the perc. tab down I get 16 vdc? ? should be 16 vdc? ? ? ? ? ? INPUT VOLTAGE FROM PRESET TABS

At pin 7? ? ? "? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? I get 2.5 vdc? (it should be 14 vdc)? ? ? ? ?INPUT FROM REITERATION TAB

At pin 2? ? ?"? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?I get 14.5 vdc? should be 14.5 vdc? ? ? ? ?TO PERCUSSION KEYING

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On the power amp board:

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#8 = 0 mv should be 800 mv? ? (FROM PIN #3 RECOVERY & NON-VIBRATO 800MV P-P)

#2 = 16 v? should be 15v? ? ? ? ??

#6 = 0 mv should be 500 mv

#19 = 0 v? should be 15v

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So somethings not right ...

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