[Radioroslyn]

Nice bit of troubleshooting!!!
Terry

[RGallahue]

To all:

Tested with a lightbulb apparatus I had to Rube Goldberg together. Tested the apparatus first, bulb lit without problems.

First run - visual; Connected primary ends in series with the bulb, no glow. Grounded the secondary, and got a low glow.

Second run - w/DMM:Repeated but with the DMM now in series with the bulb. As in the first step above, primary ends in series with bulb and DMM, returned to same voltage, no reading on the DMM. Grounded the secondary and measured about .05 amps.

Inductance is indeed a wonderful thing...

So it would appear that the transformer passes this test?

Richard

[morzh]

By "grounded", what do you mean exactly?

If "shorted together", then, yes, seems like the xfmr passed the test.

[RGallahue]

One primary side is already connected to chassis ground. I used an alligator clip to make a temporary connection between the other secondary wire which goes to the speaker and chassis ground.

So, if the transformer is indeed OK, where elsewhere might I look? I have been through the circuit fairly carefully.

Thanks,
Richard

[morzh]

You mean "one secondary side is grounded". None of the primary suides are grounded.

[morzh]

All in all, even if the old xfmr is good, probably does not hurt to buy an inexpensive xfmr and replace it temporarily to see if it works.

Use know good tubes, see if they are ok. If yes, then install the old xfmr and carefully bring it up and see if it works.

We don't know, the tube that was gone might've been just bad.

The higher than normal voltages question remains of course. Without the load it is hard to tell how much they should rise. I suspect they are OK, as it is hard to imagine that the power transformer, having a mind of its own, all of a sudden decided to step up the output a bit more. And the rectifier tube may only make it lower, if anything, unless shorted, in which case you'd see AC, not DC output.

Well, you'll need to do some tinkering.