[HAM] I'm stumped on a model

[erno palonheimo]

On Tue, 2003-11-04 at 08:44, gandj wrote:

> Hey, lounge lizard here. A friend of my fathers recently purchase a hammond
> organ for 30 bucks. Curious of course I checked it out. I didn't have enough
> time to remove the backing and see the model plate number but I haven't seen
> anything quite like it. It has speakers mounted (inset) on the sides and the
> front and it is definetly a spinet. It has a built in percussion unit, and a
> million other switches. The switches I remembered were: vibrato celeste and
> chorus (I'm not certain if it had scanner), presets like mandolin and
> guitar, a switch that said "silent" and something else (memory fails as to
> what it was), it had one octave of foot pedals, and an expression pedal,
> these eight or so switches beside the lower keyboard I haven't seen before,
> drawbars, two three octave keyboards, and a few other things. Oh and it had
> this neat light built in that shone from the bottom up on to the music, a
> feature I have never seen before. It had the bolder font on the hammond
> logo, it had plastic cheekblocks and only one button to start (but it
> doesn't sound solid-state) so I know it is mid to late 60s and early 70s.

Sounds pretty much like a T-5xx series spinet. These have tonewheel
generator and scanner vibrato, but the amplifier section is solid-state
and has aggressive keyclick filtering. This can be cured, though:

http://www.tonewheel.de/hammond/t-modifications.htm

>     The major problem with it is this oscillating hum that is there all the
> time (or at least the 10 or so minutes I fooled with it) and it's pretty
> overpowering. I wasn't sure if this was the product of the magnetized
> filings I always hear about, or if it was more serious than that. When you
> turn down the expression pedal (and, consequently, the whole organ) it goes
> away. Anyways, if it is a big problem, it's not worth my money (I don't know
> how much he's selling it for), if it is a small problem it is "definetly an
> exspensive and timely thing to correct, lowers the value of the organ, I'll
> be generous and give you 60 bucks" *wink, wink, nudge, nudge*.

Power supply filter caps could be a likely cause for this.

-- 
erno palonheimo, lousy keyboardist & 2nd-class tech, +358 40 542 9606