GE BA-5 with BP-4-A PSU found, and now?

[mkiijam]

I have a GE BA-5 compressor with its power supply.

Does anyone have the schematic for the power supply? I'm planning on a full restoration, but figured I should recap the power supply first and take it up slowly from there.

 

[mjrippe]

Is this the one?

 

[mkiijam]

Very close maybe, if not exact.

Mine is marked BP-4-A . It is complemented with 9 glass tubes, 6 dual 20-20uf octal caps, amount a few other things.

I'm not sure if I am seeing these ALL represented in the schematic.

The V+/- output look right on first inspection.

 

[mkiijam]

So, the question now is: To rebuild this supply for the compressor or build a new one from scratch.

I'm trying to understand why these transformers are SO MASSIVE!?

 

[emrr]

It's a simple rebuild.  There are several versions.  There's another thread about these. 

 

[mjrippe]

Rebuild.  Test tubes, replace electrolytics, check values of resistors and replace as needed.  This PSU was overbuilt for broadcast reliability.  It will also retain value if restored rather than replaced.

 

[mkiijam]

Yes, I am on my way rebuilding it.

Advice on the "PYRANOL" caps? Replace with?

 

[mjrippe]

Yes, I am on my way rebuilding it.

Advice on the "PYRANOL" caps? Replace with?

Glad to hear that.  I'm not sure what Pyranol caps are, but if they are not electrolytics or wax/paper they are probably fine.  Film, ceramic, and mica caps *generally* do not need replacing.  If they are showing leakage then of course they must go, but replacing them without testing is wasteful.

 

[emrr]

Doubtful the Pyranol need replacing unless value is way off or they are leaking oil.    They are paper/oil caps.  Very high reliability outside of physical leakage. 

 

[Brian Roth]

Keep in mind that Pyranol caps have PCB oil inside, and are potentially harmful to humans or the environment.

https://en.wikipedia.org/wiki/Polychlorinated_biphenyl

Bri

 

[emrr]

.....which is why you replace them if leaking.....tends to be from environmental conditions from what I’ve seen in the field.