a real challange?

[Yamamaya42]

https://imgur.com/ASrbzio

Oh yeah,,, it's bad.
52 ohms R120 is toast...

EDIT
R122 is also bad
what must have happened, C90 went bad and took out the resistors, no wonder i have weak HV :/
i need a set of 1w resistors now

[Yamamaya42]

what I don't get is why do they have the Parallel resistors on g2 on the HOT, 22k & 18k...
does it have to be EXACTLY 9.9k there? or would a 1 10k 2w work fine?

I mean, right now they have the 2 in Parallel , both 1w, the 18k is very bad, so i gotta replace both, do I have to put them back exactly as they were? or will 1 larger one do?

[Kevin Kuehn]

Originally Posted by Yamamaya42

I mean, right now they have the 2 in Parallel , both 1w, the 18k is very bad, so i gotta replace both, do I have to put them back exactly as they were? or will 1 larger one do?

Hard to guess why they did that other than parts availability and wattage. I'd be comfortable with a 10k metal oxide in that location, although I'd be tempted to bump the wattage up to 5, just to give it an easy life. But in theory modern film and oxide resistors can endure more heat per surface area than the old carbon composition variety.

[Yamamaya42]

the horizontal output tube is most likely bad / weak, replaced the bad ( scorched ) cathode resistor 100 ohm, tested @ 45, replaced the pair of G2 resistors with a large 10k, All voltages look OK and match what is shown in RCA 630ts service manual, Cant measure plate voltage with it running, but with wire removed, its 318v at the wire.
the waveforms even are pretty much spot on what is shown in the 630ts service manual for the HOT, so all that is left is a bad tube

[Yamamaya42]

ummm, is this a problem, i really hope not, cause if it is, I'm screwed.

https://imgur.com/x1izfje

between point 2 -3 I get 250 ohm on a DVM but from 1 - 2 it's 95.6 ohms.
is the FBT bad ? T_T

there has been no red plating of the HOT..

[JohnCT]

Originally Posted by Yamamaya42

ummm, is this a problem, i really hope not, cause if it is, I'm screwed.

https://imgur.com/x1izfje

between point 2 -3 I get 250 ohm on a DVM but from 1 - 2 it's 95.6 ohms.
is the FBT bad ? T_T

What I would do is see if there's an alternate schematic of the TV, like a SAMS or Riders to be sure it's not a mistake. Otherwise, it looks like you have some adjacent turns shorted.

A ringer would show that, as would something like a B&K analyst or Sencore VA48 etc. that would drive the flyback directly.

John

EDIT: that looks a lot like a 630, and that looks like RCA's drawing... If it's a clone, then RCA also has 180 ohms for that part of the winding.

[Yamamaya42]

Originally Posted by JohnCT

What I would do is see if there's an alternate schematic of the TV, like a SAMS or Riders to be sure it's not a mistake. Otherwise, it looks like you have some adjacent turns shorted.

A ringer would show that, as would something like a B&K analyst or Sencore VA48 etc. that would drive the flyback directly.

John

EDIT: that looks a lot like a 630, and that looks like RCA's drawing... If it's a clone, then RCA also has 180 ohms for that part of the winding.

then this has quickly become a lost cause, and wasted time and effort, as the chances of finding a replacement a pretty much none, unless there some how a way to fix it, which i really doubt..

this really sucks

[JohnCT]

Originally Posted by Yamamaya42

then this has quickly become a lost cause, and wasted time and effort, as the chances of finding a replacement a pretty much none, unless there some how a way to fix it, which i really doubt..

I'm a recent joiner to this forum, and only recently been bitten with the vintage TV obsession, but aren't 630s like the most common postwar TV ever made? Must be tons of used parts available, perhaps from someone here.

BTW, on another thread, I was chided (gently!) about not doing a full recap on an old Andrea TV before doing any other work on it. My rationale was that if it had a bad yoke, HV transformer, or CRT (metal cone), it would be a waste of time on a rare bird like the Andrea. Once I verified the hard parts were good, I scheduled it for a full recap.

But I don't think you have a dead end here with a 630 clone. Best of luck.

John

[Yamamaya42]

this is just not making any sense...

IF the flyback was damaged/ had a shorted turn, would I not also get weak Horz sweep at the yolk as well as poor HV?

BUT...
https://imgur.com/YanCyvE
they are perfect...
https://imgur.com/30SwwKS
Cathode of Damper

https://imgur.com/QAX2DQS
input to horz yolk coils , pin 4 of damper, 100x probe


this is getting very strange
if there was a FBT problem, should i not see it in the sweep output?

[bandersen]

Yes, I would expect sweep issues if the was a short in the windings. Does adjusting the drive control do anything ? Also don't assuming anything until you can try a different 6BG6.
It's not the most common post-war set, but a lot were made. Total TV production in 1946 was only something like 180,000. Replacement flyback should not be too hard to find though. I believe a Thordarson FLY-1 is what you'd want. It was used in many other brands and models too.

[Yamamaya42]

flyback removed...

https://imgur.com/VQodl6R
https://imgur.com/qw1tylZ

There are cracks in the " doughnut" but not too bad, right now I think there is nothing to loose in covering the windings with corona dope.

at this point I tend NOT TO believe what the meter is telling me, as when I had this apart, I took the chance to check the 2 resistors under the HV rect base, the 3.3 ohm to the heater is OK, but the 1m going to the CRT anode lead checked wide open, VERY BAD, even with it like that, I was getting 5kv at the CRT.
So...
I have a new 6BG6G coming, gonna try and dope the FBT as best as I can, replace the 1m, put it all back and see what happens.

[Kevin Kuehn]

Originally Posted by Yamamaya42

flyback removed...

https://imgur.com/VQodl6R
https://imgur.com/qw1tylZ

There are cracks in the " doughnut" but not too bad, right now I think there is nothing to loose in covering the windings with corona dope.

at this point I tend NOT TO believe what the meter is telling me, as when I had this apart, I took the chance to check the 2 resistors under the HV rect base, the 3.3 ohm to the heater is OK, but the 1m going to the CRT anode lead checked wide open, VERY BAD, even with it like that, I was getting 5kv at the CRT.
So...
I have a new 6BG6G coming, gonna try and dope the FBT as best as I can, replace the 1m, put it all back and see what happens.

If the 1 meg anode lead resistor is open(really good chance) they can still arc some voltage across the deteriorated carbon. Why not disconnect the anode lead from the CRT and see if your high voltage comes up, and if not also check on the fly end of that resistor? And NO those Fly 1 style transformers are not unobtainium.

[Yamamaya42]

1 meg resistor replaced.
flyback put back in.
https://imgur.com/NV9COl1

taken with no CRT hooked up.

YES, adjusting the drive control has slight effect on HV, by about 1.5 volt.
At this point, I'm not sure if I believe what the DVM told me or not, as the HV is now normal. and the sweep looked OK,I did look briefly for a "Fly 1 " but did not get any hits, if it is really bad I'd have to look harder, but I'm not sure where


EDIT--
just hooked up a CRT and the HV went up to 11kv.
i am really doubting the FBT is bad now...

[Kevin Kuehn]

Originally Posted by Yamamaya42

1 meg resistor replaced.
flyback put back in.
https://imgur.com/NV9COl1


EDIT--
just hooked up a CRT and the HV went up to 11kv.
i am really doubting the FBT is bad now...

Sounds like all is well. The dag coating acts as additional filtering, or if no door knob cap the only filtering.

[Yamamaya42]

The IF is obviously going to need work. :/
https://imgur.com/jT1W485
https://imgur.com/VIv1zqV

yes, I now know I have the yoke on backwards :O

https://imgur.com/nFmlP4w

https://imgur.com/oGGx7gd
but this is through the tuner