Fixed it 'till it broke. What now?

[Stanislao]

Main problems were a pair of dead drawbars and a reluctant motor. Thing would start, but only if the shaft was nudged a bit. In hindsight, I should have left my H-100 in this state. But of course, I called supposedly the only guy in South Dakota that repairs Hammond Organs.


The repair guy concluded that the issue was an under-lubed motor, nearly blown. Seems likely enough, especially as the motor had been doused in Hammond oil by the previous owner. Repair guy installed a new motor, and things got worse from there. After three and a half hours and a two new run capacitors, the second a 4 mic instead of 3 micro-farads, my organ was humming along happily. Ish. She was out of tune. Not just a bit, but as much as a perfect fourth sharp, then down to a half step, then in tune. We turned it off, turned it back on again, found it a half step sharp again. At this point it was a bit late in the evening, and we decided to call it until Friday.


A few hours later, I try to turn my organ on, and was greeted only by a disturbing silence. Motor refuses to spin on its own power. Attempting to nudge it produces a very gritty resistance, with the occasional kick as something tries and fails to work. Everything else in the organ seems to work fine, tubes glow warmly, radio comes through my household wiring nice and clear as usual.


At this point, I really don't trust the guy. While knowledgeable about Hammonds in general, he didn't know much about the H series in particular. While I'd like the old motor back, he took it with him. It occurs to me that I could have accomplished the same result by getting drunk with a friend of mine and breaking out the soldering iron.

[Wes]

Open up the motor and see what's wrong. What have you got to lose?

[enor]

A perfect fourth _sharp_? Sounds very very odd... I don't really see how that could come about in the first place. Getting the motor to spin faster than the normally indiced magnetic field is a sign of something very unusual happening.

*edit*
on second thought, the motor spinning too quick would be a sign that a couple of the stator poles aren't getting energized like they should, for one reason or another. Broken motor, broken wiring, broken run cap. Or indeed a miswire between run cap and motor.

[tucsondave]

Why would he try two different capacitors when the proper value is on the motor label?
Have you checked that 4mfd is the correct one?

td

[Stanislao]

on second thought, the motor spinning too quick would be a sign that a couple of the stator poles aren't getting energized like they should, for one reason or another. Broken motor, broken wiring, broken run cap. Or indeed a miswire between run cap and motor.

The motor was "rebuild," perhaps not well. It is entirely possible that the connections were miswired, the guy admitted to having little familiarity with the H series.

Why would he try two different capacitors when the proper value is on the motor label?
Have you checked that 4mfd is the correct one?

td

The correct capacitor is three microfarads. That was the first replacement he wired in. After his replacement motor was reluctant to start, perhaps because it was broken to begin with or wired it wrong, he decided to put in the larger capacitor. I, having not familiarized myself with this part of the organ, just nodded my head like an idiot.

[Wes]

The size of the capacitor controls the phase shift of the AC waveform. Using a larger capacitor servers no purpose whatsoever, and can add extra stress on the motor.

This guy doesn't know anything about self-starting motors, not just the H-series of organ. I think it's safe to assume the generator and scanner spin freely without the motor connected, although you should check that just in case.

Motors are pretty simple, and if a motor is bad, an electric motor shop can often rebuild it. It might be cheaper to buy one from eBay, though.

If you hook the motor up with no load, it should start easily and whirr away. When you spin the motor, you should feel free little resistance, and it should be even all the way around. The shaft should have no radial play, but signficant axial play is completely normal.

Wes

[Bobmann]

Send me a private message. I have a motor that you can have for cost of postage.

Bob

[Stanislao]

Well, the motor spins freely when the organ is turned off and unplugged. Turn it on and it doesn't budge.


Am I the only one that thinks the hack repair guy wired something wrong?

[jdoc]

does the generator spin freely? It should coast!

[Wes]

Yep, check both the generator and the vibrato scanner (it's belt-driven on yours, right?)

[Stanislao]

They both spin quite nicely.

[Wes]

What happens if you put a bit of load on the motor?

[Stanislao]

Don't have anything in the way of test equipment, not even a multimeter. I can tell you that the thing won't budge if the organ is turned on.


Mr. Hack Repair Man didn't simply replace the motor and capacitor, he rigged some sort of wack-ass pile of wires and connectors. My fault for trusting the guy and not watching him. Some ground wires loop back on into empty ports. At this point I think I'll just track down a circuit diagram and either wire it myself or have a friend do it. By now I trust most of the politicians I've met more than Mr. Hack Repair Man.

[enor]

If it holds still with power applied, that further supports the thesis that only some of the stators are getting "juice". Miswire or fault - could be either at this point.

[Stanislao]

Yep, solid when turned on and disconnected from the scanner and generator. Spins freely when power is off. Original motor is back in, before Mr. Hack Repair Man touched it thing would turn fine once started.


Jackass.


Can anyone tell me what the correct oil for the motor and vibrato scanner is? Mr. Hack Repair Man insisted on 3-in-1 oil, claiming that generator oil iss too light. Sounds possible, but I don't trust this guy and haven't seen similar advice elsewhere. Vibrato scanner is of the square type, and got quite a lot of 3-in-1 from Mr. Hack Repair Man, as did the old motor which he "rebuilt" and put back in.