Help with Gulbransen Theatrum 3218W organ

[Foster]

I have bought this organ (and probably paid too much)
Everything is working, except the solo tabs. They are soft and the higher pitches are dead.
The draw bars are working, except the 4' pitch on the solo.

The rhythm unit will not latch, probably a mechanical problem.
The Leslie celeste is also dead - I suspect the relay in the Leslie.

I have a photocopy of the workshop manual, but really need practical help.

Foster
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[Foster]

I have sorted out the rhythm latching problem, and after many dry joints, have all the functions working.
I have been checking the voltages coming from the piston logic, and then the reverb/reit board. The voltages are all over the place, and very low.
The solo voltage goes via the latch/unlatch piston, to switch from solo to draw bars, but the color code seem to change from green to gray, but the stop tab rail has a green wire to the common.
Any ideas folk ?

[johnbeetem]

When I see voltages all over the place the first thing I do is check the battery on my multimeter. Sorry I can't help with the Gully.

[Foster]

Hi Johnbeetem,
My meter is fine, so I bypassed the reit board, and connected the piston straight to the solo common.
Now most of the solo tabs are working. There is a 8' voice sounding when no tabs are selected. Where can I look to solve the problem ?
I must say that the 3218W design is well thought out.

[johnbeetem]

Hi Johnbeetem,
Now most of the solo tabs are working. There is a 8' voice sounding when no tabs are selected. Where can I look to solve the problem ?

Here are some general principles. Since the rest of the solo tabs are working, there's probably something wrong with the individual tab, i.e., it's stuck on. There are several ways this can happen:

1. Mechanical problem with the switch contacts.

2. Foreign substance causing a weak short. I once had a projection TV act up because of leaking coolant from one of the projectors. Cleaned PC boards with alcohol swabs and got it working.

3. Broken wire somewhere. A broken wire can cause an input to be stuck high, stuck low, or stuck random. Same with a failed solder joint or a failed IC input.

4. If the organ uses a switching matrix to read switch inputs you could have a failed diode. Those are often 1N4148 or 1N914 switching diodes, which look like small resistors.

Measure a working tab and see what happens to the voltages when you toggle it. Then look at the non-working one to see what's different.