No sound from Hammond Model A (tone wheel spins)

[stanchfi]

My son got a Model A along with a Glenntone cabinet, and it appears to start up, the tone wheel spins up and runs fine, but we get NO sound out of the tone cabinet. Apart from checking all of the vacuum tubes, what else can I check? There is a 6 pin connector going to the tone cabinet, what should I expect to see if checking the pins with a multi-meter?
Most of the troubleshooting I found online for these involves the tone generator being stuck, so I don't know where to start.

thanks
-James

[tpappano]

Do all the tubes light up? One of the “preset” keys C# thru A (the reverse-colored ones) must be selected (down) for the organ to sound. The B-flat and B keys select the left or right drawbar groups for each manual, so drawbars must be pulled out for those presets to work. The C preset key is “cancel” which releases any selected preset key. The cable from the organ to the speaker cabinet may be old, dried out, with crumbling insulation and be hazardous to use. It carries AC to power the speaker, and also carries DC voltage back to the organ to power the organ's preamplifier. The cable also has the ‘signal' conductors for the audio. As you can see, there are plenty of ways for the cable to cause problems from no sound to setting your house on fire. The internal power wiring of the organ can have the same issues and probably should be replaced if it hasn't been already. My rule when working on these is to not have them plugged into a power outlet unless directly supervised, until the wiring and cabling has been replaced, and a fuse retrofitted to the organ. None of these things are costly or difficult to do, it just takes an hour or two.
And, congratulations on your find! I just missed a chance to get an “A”, the seller decided to keep it!
Other stuff may need to be done to the amp, etc.

edit: be sure the generator really continues spinning. You can easily hear the “start” motor, but in that heavy cabinet the generator can be hard to hear when running normally. If there's a motor or lubrication issue the generator may slow to a stop without your hearing it.

still more: If you haven't already, you can download a service manual that covers all the early models and provides a wealth of info.

[tpappano]

I just seem to be going on and on 8)
A caution about the amp in the speaker cabinet- if this system hasn't been run in the last few years, the filter capacitors in the amplifier can loose their ability to withstand their intended operating voltage. Suddenly powering one up like this may blow the amp's fuse if it has one, or worse burn up the power transformer. So, have you any idea when your setup was last used?

[tpappano]

A helpful thread:
https://organforum.com/forums/forum/...older-consoles

[Drawbar Dave]

The model A, like the BC and other early models will require B+ voltage from the tone cabinet to run the amplifier. Only the tube heaters in the amp get their ac from the organ through a dedicated transformer. It's been a while since I looked at one of these two tube amps but check for DC voltage at the B+ and ground terminals on the front of it.