Need advice on Zenith Porthole power-up after resto

[ShartZenith]

We've been working on this Zenith and have completed recapping, test tubes, etc.
When we powered up the Zenith we got to 110VDC we got smoke from under the chassis in the area of the 6W4 tube which was glowing very red hot. Could the problem be related to the flyback since its on the same circuit? How should we test the flyback for continuity? We tested it initially during restoration but the values we got at that point didn’t seem to be correct.
model H2445, chassis 24H21.

Thanks for any help!
Steve and Bob

[cwmoser]

Hey Steve, did you Ohm out the Flyback?
Does your Schematic show ohm values for each coil winding in the Flyback?

I would check each winding, and then make sure that each coil winding is connected
properly.

Also verify that the high voltage capacitor is in place.

Be very careful around that Flyback and make sure you remove power and discharge the CRT before working in there.

Carl

[ShartZenith]

Carl, I think we did ohm it out but it's been so long ago I've forgotten. We'll probably do it again on our next working session given the current circumstances. I coated the flyback winding with some rubbery stuff but all four of the leads are intact and accessible. Thanks!

[old_coot88]

Originally Posted by ShartZenith

We've been working on this Zenith and have completed recapping, test tubes, etc.
When we powered up the Zenith we got to 110VDC we got smoke from under the chassis in the area of the 6W4 tube which was glowing very red hot. Could the problem be related to the flyback since its on the same circuit? How should we test the flyback for continuity? We tested it initially during restoration but the values we got at that point didn’t seem to be correct.
model H2445, chassis 24H21.

Thanks for any help!
Steve and Bob

If the 6W4 is lighting up red plating that badly, it sounds like you have a hard short-to-ground either from the cathode (pin 3) or from the linearity coil to ground. That'd be the first place to start looking. See schematic..
http://www.rsp-italy.it/Electronics/...237-Riders.pdf

[Username1]

Originally Posted by old_coot88

If the 6W4 is lighting up red plating that badly, it sounds like you have a hard short-to-ground either from the cathode (pin 3) or from the linearity coil to ground. That'd be the first place to start looking. See schematic..
http://www.rsp-italy.it/Electronics/...237-Riders.pdf

I agree, you first need to check to see if there is a mistake made when this area
was updated. A simple mistake could be causing this problem...

.