Old iron PT Specs (needed)

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gahult
Posts: 393
Joined: Sun Jun 01, 2008 6:20 pm
Location: Rutledge, GA

Old iron PT Specs (needed)

Post by gahult »

Does anyone have specs. on these??

Sparton #'s

AB-4039-1

And

344039-1

They are old pulls out of TV's I think.

The 344039 has a pair of wire tagged 400v not in use.

Thank

Gary
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Phil_S
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Re: Old iron PT Specs (needed)

Post by Phil_S »

This isn't exactly shooting fish in a barrel. I don't think you will be getting a direct reply anywhere. You will need to tease it out yourself through testing.

Start by identifying the primary winding -- usually black, black/white, possibly black/red. I'd expect the primary R to be maybe 2-10 ohms. and generally, the lower the ohms, the higher the mA rating. It should be a winding with only two wires.

Then, measuring ohms, see if you can figure how the secondary windings group up. Look for typical colors as a hint (red=HT, green and yellow for filaments), though there is no saying the manufacturer followed any particular standard.

Once you've settled on the primary, use a couple of wire nuts to attach a suicide cord (stripped on one end, plug on the other), plug it into the wall supply and see what comes out on the secondary. Remember, these are unloaded AC voltages. In use and under a load, rectified B+ and filament supplies will drop. It's not unusual to see 7v on the 6.3v winding and 5.5v on the 5v winding. You may want to take the safety precaution of using a surge protector or a light bulb in series with the primary for the purpose of limiting current draw.

If it's a TV transformer, it may not have any filament windings. It might have several low mA secondaries of voltages not particularly useful in guitar amps. Maybe these are eBay fodder?

If it shows promise, post your findings (voltage in, voltage out, ohms across the various windings). Assuming I see your post, there is more you can do to tease out the mA rating of the windings and I'll try to help you. Be forewarned that I am an amateur without engineering background, but I've done some of this type of discovery work and it isn't rocket science.

I'm assuming these are both power transformers. If you think one is an output transformer, the treatment is very different. Don't even think about running 120vac on the primary. Read here:
http://www.radioremembered.org/outimp.htm
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gahult
Posts: 393
Joined: Sun Jun 01, 2008 6:20 pm
Location: Rutledge, GA

Re: Old iron PT Specs (needed)

Post by gahult »

Thanks for the reply.
They are both power Txfrms
One is in a 250W linear amp I built way.......... back.
The other is also in a linear maybe 1Kw my friend (now deceased) built way.....back in our ham radio days.
So, it should not be hard to disconnect and check the outputs, just thought I'd try the easy way and see if some one had the info somewhere :)

Thanks

Gary
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