[HAM] CV - no sound

[Dave Bishop]

A typical CV will have a six pin female connector in the same box as the 
electrical cord.  Is this where you are connectiong the cable for the PR-20? 
You can trace the wires from that socket to the organ power strip and 
pre-amp, and we can probably tell you if it is hooked up correctly.  The 
27-1 is a wiring harness for a 147 style Leslie hookup kit. It has only five 
pin holes.  The harness connector plugs into a Leslie 26-1 connector box. 
That hookup will not match the stock wiring in a PR-20.  For the PR-20 pins 
1 and 6 are signal, pin 5 is B+, pin 2 is ground, and pins 3 and 4 are 
120VAC.  For a 147 pins 1 and 6 are signal, pin 5 is Leslie speed switching, 
pin 2 is Leslie speed switching, and pins 3 and 4 are 120VAC.

The PR-20 generates a 280 volt current called B+ that travels back up the 
cable to supply the pre-amp tubes.  If this is not being supplied, the tubes 
will light but you won't hear anything, even with headphones.

Try the headphones attached as follows:  one lead to a single G terminal and 
the neutral  (ring) to the pre-amp chassis ground-- not the other G 
terminal.

Have you checked that the rheostat is actually moving when you press the 
expression pedal?  Have you pulled all the drawbars out and pressed the 
preset keys B or A#?

Have you removed all the tubes (cold) on both units, sprayed the sockets 
with De-Oxit, and re-inserted them a few times to remove the corrosion?

Regards,

Dave Bishop