[sdiy] OT: Hammond Organ

[Roy J. Tellason]

On Saturday 11 June 2005 05:37 pm, James Coplin wrote:
> Not to sound patronizing, but do you know how to turn a Hammond on? 
> Forgive me if you do but it sounds like it is not fired up correctly.

He mentions "bottom manual dead" (perhaps meaning that the top one wasn't) and 
"rhythm section",  which is not something that appeared on the real early 
ones that you're talking about.

> You need to hold the start switch up (usually on the left) until it gets
> going good (5-10 seconds) and then flip the run switch (usually on the
> right) and let go of the start switch.  If you don't do this, nothing will
> work right.

Yep!  For those real early models.  However,   Hammond did make models that 
used tonewheel generators a little later on that didn't need a separate start 
motor,  the running motor had enough torque to get it going.  And then later 
on,  they did make models which were entirely solid-state,  as well.

> Good luck!
>
> James
>
> > -----Original Message-----
> > From: owner-synth-diy at dropmix.xs4all.nl [mailto:owner-synth-
> > diy at dropmix.xs4all.nl] On Behalf Of Michael Ruberto
> > Sent: Saturday, June 11, 2005 4:12 PM
> > To: synth-diy at dropmix.xs4all.nl
> > Subject: [sdiy] OT: Hammond Organ
> >
> > I finally found some time to poke around inside my new T-524C spinet.
> > Suprisingly, the guts all seem in good shape and remarkably clean - no
> > dust
> > at all! 1st time I powered it up there was grinding sounds inside,

I wonder if this one had the built-in Leslie speaker?  I don't remember any 
more,  though I'm sure that I encountered that model somewhere along the way.

> > a constant loud hum from speakers, bottom manual dead, and the rythm unit
> > could be heard faintly when the volume was alll the way down. I don't
> > know the 1st thing about troubleshooting this monster. however, I've
> > found that it likes air conditioning. after running the AC for awhile the
> > lower manual started working, the grinding stopped, and the rythm unit
> > finally shut up. the hum is still there and it seems to be coming from the
> > bottom manual. Turning on Vibrato for the bottom manual affects the hum so
> > I'm thinking it's a stuck note.

Could be.  I'd look at the keyboard first and see if there's a broken contact 
in there somewhere.  I don't recall this specific model but a great many of 
those organs had keyboards that you could swing up, some of which required 
screws to be removed first,  some of which didn't.  (Look for it,  it's 
obvious if the capability or the screws are in there.)

> > I really need information before I try fixing this any further. someone
> > already thoughtfully provided me with schematics but I'm still looking
> > for a source for the service manual, parts, and modifications. I very much
> > appreciate any help here.

Look for capacitors that are showing any signs of leakage,  too, or,  if 
they're the units that are black with one end red (REAL common in Thomas 
organs) look for cracks in them.  Sounds to me like that's at least part of 
your problem.