[sdiy] thomas organ questions

[Roy J. Tellason]

On Sunday 14 October 2007 15:37, bill bigrig wrote:
> Howdy,
>
>  there is a thomas 145 organ at a thrift shop for
> $46.50. Does this unit use any 5024 chips? It also has
> a Leslie speaker although it is only high speed and
> only turns audio on/off. Did they make an electronic
> sim back then or is there a spinning speaker in there?

I used to work on organs quite a bit,  though it's been a while -- was 
probably around 1985 or so when I stopped...

I also worked for a dealer for a while that sold Thomas organs,  which was 
probably around 1979 or 1980 or thereabouts.

I don't remember any electronic leslie type of setup, I'm pretty sure those 
that had the leslie feature had an actual spinning baffle (not speaker) in 
there.

I don't recall from that model number what they used for tone generators,  
either,  and unfortunately don't have much of my service data any more (I 
used to have service manuals on darn near *all* of thier stuff).

I just looked in my files and found a manual for a 125R,  no telling whether 
that's close to what you're looking at or not.  That one uses discrete 
transistor oscillators for the top octave,  and "packaged circuits" (think 
ceramic capacitor looking material on the outside,  rectangular shapes,  and 
several wires coming out on one of the longer edges) for dividers.

I'll also add this about any number of older Thomas organs -- if,  on opening 
the unit,  you spot any electrolytics with black bodies and one red end,  
rip 'em ALL out and replace them.  If they're not bad already they will be.  
I've often observed those with actual cracks in the cases...


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