Older kit, need coherent instructions

[YankeeDespot]

I recently moved to NE Arkansas, and a frequent conversation includes statements like “I lost my (wife, job, house, limb) from when I used to smoke methamphetamine.”  Never meth.

well, I don’t even have that excuse. So of course I had a found to the ground lug off one of the green wires, so now am getting 3.2 off of each green wire, and so each tube pin gets 3.2 VAC.

When I tried to measure the yellow wires into the rectifier socket, my multimeter, set to AC, would beep and give nutty readings. But low, decimals…0.234, stuff like that.  So I just tried Dc, and that’s when I got the 380vdc.  I pulled the wires off the socket, and now get 3.7 vac from one leg, and .6vac from another with them unconnected. I’ve used two different dmms so don’t guess that’s the problem.

In all the fiddling I broke a pin of the 9pin socket, so will be ordering more, and I have a spare 8 pin, so I’m going to rewire that rectifier with a new socket, just because, why not?

I’ll post results, and if I can figure how to rest the transformer.

Thanks for staying with me.

[YankeeDespot]

I checked impedance of leads to OT, and there are no shorts. The ohm reading were what are to be expected.  I powered up with the primary connected and the red yellow grounded. Unconnected, across the leads(not to ground) I got 6.5vac for green wires; 5.15 vac across yellow, and 660 vac across red.

I always have the output to a speaker or an 8ohm resistive load. I see no shorts on the OT.

any ideas?

[Andy]

Those sound about right. The tubes need 12.6VAC to run those filaments. So you will need 6.3V to pin 9 and 6.3V to pins 4-5 on the preamp to make that work and then 7 and 2 on the power tube. Your previous measure of 3.2 off each green would be problematic.

[YankeeDespot]

Here’s what the PT is doing unhooked.

Checking continuity, between yellow wires, .6 ohm, between red, 331 ohm, green to green .3, so there’s no major shorts in there, but:

measuring ac voltage with a true rms dmm

Across green wires 6.79 vac, and across yellow 5.3. Is that right?   If those are half what they are supposed to be, could I run one leg to one side of the tube and ground the other?  Think I read that somewhere.

Please advise on what you think about the health of the pt.

 

thanks.

[Andy]

I think that sounds ok. The 12.6 comes from 6.3V to the 9pin and 6.3 to the 4-5 pins. So I don’t think there seems like a PT issue.

[Author]

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