1952 Motorola Bakelite tv

[Radiotronman]

Here is the chassis ready for new parts. You can see the copper UHF tuner in the center.

[Radiotronman]

After recapping the chassis, I briefly had a bright horizontal line. I replaced a couple more remaining bumblebees, turned it back on and nothing on the CRT at all. I get sound, but that is it. My fusistor is good, I've swapped hv rectifier, horizontal oscillator and horizontal output tubes with no change.

[Radiotronman]

I still can figure out why I have no high voltage. Would a bad yoke cause this? One lead goes from the flyback to the yoke.

[Eric H]

Have you rechecked those last couple caps you replaced? If you had some HV before but none after possibly something got hooked up wrong, or maybe it threw the horizontal oscillator so far off it quit, try adjusting the Horiz Hold and see if you can hear it running.

[Radiotronman]

I can hear the horizontal and vertical running. I thought I'd triple checked everything, but I'll check again.

[Radiotronman]

The hv disappeared while it was on, before changing the last capacitors. So I'm not sure what failed?

[WA3WLJ]

Great website, very interesting reading.

[Radiotronman]

I still can't figure out where my high voltage is lost. Capacitors and resistors in the horizontal oscillator and can't find anything wrong...any suggestions?

[Electronic M]

Have you compared voltages at the H out tube base to what the schematic calls for?

[Radiotronman]

The horizontal output voltages are supposed to be -25v at pin 5 and 150v at pin 4. I have -770v at pin 5 and -225 at pin 4. So what is happening here?

[Eric H]

Are you sure your meter isn't busted? I don't think that set could produce 770 volts in the low voltage supply under any conditions, not without something blowing up.

[Radiotronman]

Yeah so my meters batteries must be getting low. I actually get 124v on pin 4 and -115v on pin 5.

[dieseljeep]

Originally Posted by Eric H

Are you sure your meter isn't busted? I don't think that set could produce 770 volts in the low voltage supply under any conditions, not without something blowing up.

It doesn't take much to damage a digital meter, even a Fluke.
They pick up a spike and give all kinds of whacko readings. Check the fuse and the battery.

[Radiotronman]

I can't figure out what's wrong, everything seems to match the sams fir it. I do notice that the horizontal output tube played glow red, which usually means a bad electrolyric of miswire , but where?

[Radiotronman]

The hv output tube no longer glows red, but high voltage is no where in sight. After spending the better part of the day checking and rechecking things, I can't figure it out. This might be one of those sets that gets put back together and move onto another set.