No sound on a Conn Theatrette

[Guest]

Hi all, my father has a Conn Theatrette Model 551 type 3 the sound has gone. He has called an organ engineer out who could not diagnose the fault, the engineer then sent for a circuit diagram and spent 2 hours with the organ without diagnosing the fault. He has gone away to think about it, has anyone any ideas. We are based in Wolverhampton, UK.

Any ideas would be really appreciated.

[andyg]

1) The number of organ engineers in the UK is very small, the number who can work on oldies like this even smaller. You have to get the right person. Hopefully, your father has found one. The organ is old enough that there are no custom chips etc in it, but Conns do have their own special issues, some of which can be hard to fix.
2) Remember that the organ has a market value of zero, as has almost any 45 year old organ. Sentimental value is a different matter entirely, but do watch the spend here. There may well come a point when repairs become economically unviable and your father will have to make a tough decision.
3) You've come to the right place for information and I'm sure one or two of our experts will be along shortly. We need more info though:

a) Is there no sound at all or is it just the tibia voices or the reed/string/diapasons? They have separate generators and amplifiers.
b) Do the lights work?
c) Does the Leslie speaker spin on slow or fast?

[tucsondave]

In addition to andy's questions:

1. Does the organ have a headphone kit installed? If so is there anything plugged into it?
2. Is there hum from the speakers when the center terminals of the expression pedal pots are touched with a finger?

There are two pigtail fuses inside the amplifier chassis.
The 25 volt regulator is on the reverb board mounted on the left wall of the organ beneath the top. If that fails nothing will work. Look for a shorted 250 mfd capacitor and possibly an open 47 ohm resistor.

td