Gulbransen Power Supply Redux

[roughshawd]

I have a burned up transformer from a Gulbransen organ.
The power supply delivers multiple voltages to the system, but is going to be costy to repair to original. Can I replace the PS with multiple power supplys, one for each of the voltages and bridge them or something?

 

[Kabelsalat]

Yes, it's possible, but bear in mind you need negative supply voltages as well.

Also be sure each supply can deliver enough power - i.e. should be able to deliver at least same current as LM317T is capable of. Also you have the issue of getting 70V DC.

 

[bertus]

Hello,

You could replace the transformer with 3 smaller ones:


Assumed the electronics is still fully functional.

Bertus

 

[AnalogKid]

You might have to go with a hybrid solution; buy a +5 / +12 / -12 supply (commonly available as either linear or switching), and recreate the +/-35 V supply with off-the-shelf components. 35 V is a little below the rectified output of a 24 V transformer. What is the +/-35 V for, and is there any way to estimate the tolerance of that part of the instrument for something like +/- 31-33 V?

If you use what used to be called a "control transformer", these have multiple primary taps. For one with dual 24 V secondaries, using the 110 V primary tap in a 115 V environment will get the output up to 35 Vpeak.

Note that a 200 W transformer isn't cheap. What would a factory transformer cost, and what is your budget for the project?

ak