Ordered a NOS flyback and installed it tonight. Sadly, no change in functionality. No picture, and a blue glow in the 6BG6G indicating (evidently) current backing up. Disappointed. I'll take it back to the guy in CT and see what we can diagnose, now with a good flyback in.

Thanks for the offer TVDude. I may yet need more parts. Stay tuned.

The 6BG6 can have a blue glow even when the set is working perfectly, it just has a lot of current running through it.

I would bet the Horizontal oscillator isn't running, I would look closely around the oscillator tube and make sure everything is correct. It's easy enough to install a capacitor that's off by a factor of ten, .01 instead of a .001 for example.

Thanks Eric. I'll give those circuits a check. It might be beyond my capabilities though. I'll likely have to run it down to CT again for another diagnostic session.

What temperature to you all run your soldering irons at? I have trouble melting the original solder.

I like to run about 650 F, cranking up to 730 or so for large joints. Usually if it is difficult to get an old joint to melt, the contact of the soldering iron to the joint is not good enough. Sometimes adding just a little new solder helps get a well-wetted contact to help everything heat up and melt. Usually you should not need to do that, though.

I have always used higher-wattage irons, 40-45 watts typical; I do not know their temperatures, though. Also, as Tom suggested, I always put a bit of new solder onto any old joint to get it started.

Was this question answered? The HV connector to the tube doesn't look to be fully inserted. The rubber is usually compressed or flattened to some degree. I installed them by engaging one of the gripper fingers in the hole and pushed against that a bit to get the other gripper into the hole. A bit like a snap-fit, sometimes it takes some tender-loving force to overcome the spring of the connector.

If it is fully inserted yet not really grabbing on, perhaps the metal connector has lost some of it springiness. Or perhaps a less-aggressive grip is normal in this type of connector. Either way, it probably doesn't prevent the HV from working, just from getting to the tube.

Very interesting thread! You've done very well with your limited prior experience. Keep up that bulldog persistance and you'll get it solved!
-Ed

You can move that anode clip through the black boot so that it reaches the well in the CRT. Also, try prying out the prongs so they connect with a satisfying click.

Thanks Ed and M3. I've been concerned about that HV connection. I have pried the inner springy connector tabs both in and out, and have yet to achieve a satisfying "click" connection of any kind. I'll take another stab at it soon and see if I can improve it.

Hello! Just an FYI - this thread is not dead, nor is my restoration project on this TV. It's just been stalled for about 6 months. I got stuck, then got busy, and so it sat. I'm about to get back to it though. Here it is on my bench, waiting for me.

Great, thanks for the update! We look forward to seeing the progress.

I have some questions about the HV connection to the picture tube. Rather than bury it deep in this thread, I posted a new topic in the electrical/mechanical forum.
viewtopic.php?f=6&t=293398
Please take a look. If you have any helpful information, please reply here or there. Thanks!

I've reacquainted myself with this set and its current condition. Audio plays mostly fine - nice and clear, problems once in a while, tuning away and back clears it up. No video. All the tubes, including the picture tube, were tested and are good. The flyback was suspect, and I replaced it with NOS, but there was no change in functionality.

I suspect that the HV and/or the horizontal output is failing.

Question: would replacing the 1B3GT HV rectifier tube be worth trying? NOS RCA tubes are under $10 on eBay, tested, so they're not costly. But do you think it would be worth trying?

1B3-GTs are prime suspects for failing HV.

Check/replace the doorknob cap, and the resistors underneath the 1B3-GT.

Check/replace any micas in the horizontal sweep circuits.

Check the Horizontal Oscillator circuits. Check for resistors way out of spec or a dead mica. That will keep the Horizontal oscillator from, um, oscillating.

The easiest way to check for HV if you have no meter is this.


Using an ungrounded screwdriver with a well insulated plastic handle
Hold it next to the cap of the 6BG6, if the horizontal oscillator is running and all the circuitry between it and the output tube is good you will be able to draw a small sizzling arc from the plate cap of the tube.



Next step.

Repeat the process at the cap of the HV rectifier tube, you should get a much larger arc here, a quarter inch or better of nice violet arc. If you have it here but nothing at the anode of the CRT then either the rectifier is bad or the heater for the rectifier isn't lighting or there's something downstream killing it.

If your set passes both tests then I would suggest fiddling with the Ion trap while the set is running, make sure the brightness is turned up, maybe not all the way but 3/4ths or so.

I would also add make sure the arrow on the ionb trap is pointing toward the front of the CRT. If its on backwards you won't get a raster!

-George-

You might still, but the trap will be 180 degrees opposite where it would be if it were on correctly.

I turned the TV on, let it warm up, tossed a screwdriver in and got these results:
- no arc at the top of the 6BG6G tube. I have two tubes, tried both, same result, no arc.
- no arc at the top of the 1B3GT HV rectifier tube
Also, after I shut the set off I touched the 6GB6G and it was VERY hot. A momentary touch nearly burned me. When the set was on it had quite a lot of blue glow inside. As has been explained to me, the blue glow is ok - it is not the purple glow that indicates a gassy tube. It might have current backing up into it, though, if the downstream circuits aren't working. But I'm not sure how much blue glow is too much.
The small vertical-related 6K6GT tube was also had a blue glow inside - a full ring around near the top of the tube.

Is the HV downstream from the horizontal circuits, or the other way around? If HV is first, then replacing the 1B3GT might be worth a try. But if horizontal is first, then replacing it wouldn't do a thing until I work that out. Am I on the right track?