1956 GE 14" - horizontal/HV problems

[Adam]

This is another one of those sets with many problems.

I did the usual complete replacement of all paper and electrolytic capacitors a few months ago.

I have good vertical - both deflection and sync. (after replacing output trans)

I also have sound (not loud, but it's there).

Everything up to the horiz output tube seems to be working properly. (after replacing bad osc coil). I still have something intermittent that throws the horiz freq off, but goes away if I tap the horiz afc tube. (don't know if it's a connection on the board or the tube itself yet, I didn't have a 5AN8 to sub.)

Now the picture is full height, and bright, but only about 1/4 - 1/2" wide. HV is down around 1kv. Boost voltage is about 150v, should be 275v. HO and damper tubes are good, tried swapping a few in anyway, no difference. I checked across the flyback and yoke with an ohm meter, it read what it should according to the schematic.

I'm stumped, what am I missing here?

[Don Lindsly]

Check for an open cap or mis-wire in series with the horizontal yoke winding first. If all is OK, then look for an open horizontal yoke winding. Check for a shorted cap from boost to B+. Easiest way is to remove the damper and make sure the picture and high voltage all go away. Do it quickly before the filament string goes cold.

The horizontal could be way off frequency, but you will need to replace the 5AN8 before going further. Tube sockets go bad in those TVs. Make sure the socket pin holes have not spread out.

A bright picture conflicts with 1KV high voltage and 125 volts boost. Is there more you can tell us?

[Adam]

HV is really about 1.5KV.

1st pic the scope is connected to the control grid of the HO tube, so everything up to that point looks ok, vert. out of the scope is hooked to the counter, and the horizontal frequency looks ok too.

2nd pic shows what's on the screen, it should be a straight vertical line, the yoke's just turned.

Strangely, if I turn the horizontal frequency down to around 12.5 - 12.7KC, the picture gets a little wider, and the HV goes up to around 3KV.

HV drops immediately when I pull the damper tube. Horizontal yoke winding is not open.

[Adam]

I finally found the problem: open flyback. I drew a red line through the flyback where it's open on the schematic below. Notice how that connection is also made through the horiz windings in the yoke, so when I tested it in-circuit I didn't see anything wrong.

Anyone got a fly for this set?

[Eric H]

Have you checked the connections and the wires at the lugs on the fly to make sure it's not an external problem.

I have a whole chassis for one of these, glad to send you the fly out of it if you need it.

[Adam]

I can't believe that's all it was. First pic, shows one arrow to where I repaired it, one arrow to where the wire was broken where it went through the plastic part so the break wasn't readily visible. I thought this one was never going to work.

[miniman82]

You fixed it because the X-Files team was on your side!

[Adam]

Noooooo!!!!!!!!!!

I dropped the crt and it broke at the neck. I have had the worst luck with this tv.

Anyone with a spare 14QP4?

[Eric H]

Sorry to hear that when you are so close to done.
I may have one, I stuck a 14" tube inside an old Emerson cabinet, I think it was out of one of these sets and it was good.

When I moved into this house something got dropped on the tube cup of one of my 14" GE's and broke it, I found a tube for that one on eBay a while back.
14QP4's used to show up fairly regularly on eBay.

Give me a day or two to dig it out, unless you find one closer to you.