Horizontal issue with a mid 60s Silvertone (video attached)

[Kamakiri]

Picked this set up from my buddy Ed (roundscreen), and it's got an odd issue....

Below is a link to a video showing what the set is doing. It looks like the last tech in here was chasing the same problem, as the board traces were definitely resoldered where capacitors on the horizontal board were removed and tested.

I replaced a couple brown drops with that flat paint on them that looked like they'd turned black in the center, but they tested good out of the chassis.

Now, in the video, you can hear the "ticking" noise prominently throughout, but I could only hear it when adjusting the horizontal to the point of lock in, where everything goes kinda wonky....or when adjusting the brightness. I don't see any width control to adjust to bring the set in to see if I can lock the horizontal.

Model number is 2164 (1174 next to that), chassis 528.51754. I can't seem to find a Sams listing on this set.

Any advice is appreciated! Here's the video link:

https://www.youtube.com/watch?v=ieEk...ature=youtu.be

[MRX37]

Can a tube in the horizontal section arc inside?

[Findm-Keepm]

Have you replaced the Horizontal AFC diodes? It's a dual diode pack - either common cathode, or series-connected. We replaced them with silicon switching diodes, typically 1N914 or 1N4148, available at Radio Shack, 100 for $2.

What's the osc tube, a 6CG7 or 8CG7? Sams has various similar chassis in sets 515, 518 and 566 - the osc tube will dictate which sams to use.

[zeno]

Sure sounds like HV arcing. Use a paper towel tube
to find where its coming from first. The arcing can cause
the sync to mess up. Check at anode, FBT, yoke &
especially be sure the dag is well grounded. A set will
run with a floating dag & you will get the light ticking as
the HV makes little arcs to the loose ground. Can break up
the pix or cause stripes of dots in pix.

73 Zeno

[DavGoodlin]

Would you agree it makes good sweep and HV?
Maybe the AFC loop has a drifted resistor making it too "tight".

[Eric H]

I second the AFC Diodes.

[old_coot88]

Ditto the AFC dual diode.
On the ticking, another possibility is inside the CRT socket, a open due to one of the pins not making full contact.

[Username1]

Originally Posted by zeno

Sure sounds like HV arcing.
Use a paper towel tube to find where its coming from first.
The arcing can cause the sync to mess up. Check at anode,
FBT, yoke & especially be sure the dag is well grounded. A set
will run with a floating dag & you will get the light ticking as
the HV makes little arcs to the loose ground. Can break up
the pix or cause stripes of dots in pix.

73 Zeno

I agree with this... Not so much with AFC diodes. The arc sounds like
it's closer to 60hz, and did not seem to change with anything you did
in the short video. So I would look at something arcing around the vert
yoke ~ arcing to horiz windings ? Arcing to ground, picture tube ~ who
knows.... I would focus on the arcing sound. Since it's a sound, it will
not be inside a tube Sound and vacuum - something about sound not
traveling well in a vacuum.... You may even have to remove the yoke
clean it, and if something is not visible, put a clean cleanex around it,
let it arc and remove and look for burn spots.... Look for bugs, moisture,
we had Sears sets, lots of them had bad yokes....

.

[Electronic M]

Originally Posted by MRX37

Can a tube in the horizontal section arc inside?

Yes it can. I had a 6DW4 in a Zenith 19" monochrome lugable that had a intermittent cathode to plate arc/short. the tube would make a 'plink' sound and the screen would go dark for an instant, then come back and repeat....New tube cured that.

[old_coot88]

Arcing damper tubes are very common. Heater-cathode arcing is the usual failure mode, evidenced by extreme hash in the raster and sparks flying around inside the damper tube.
Tapping with a screwdriver handle will reveal if the tube has any propensity to arc.

Kamakiri's 'ticking' problem is not an arcing damper, though.

BTW, if the AFC diode is original, it's almost certain to be bad in any case, causing weak horiz sync, though not related to the 'ticking'.

[Eric H]

The ticking could just be the yoke freaking out from the whacked signals it's getting.
I hear two noises, the steady 60 hz tick and the intermittent cracking noise.

[Kamakiri]

Originally Posted by Findm-Keepm

Have you replaced the Horizontal AFC diodes? It's a dual diode pack - either common cathode, or series-connected. We replaced them with silicon switching diodes, typically 1N914 or 1N4148, available at Radio Shack, 100 for $2.

What's the osc tube, a 6CG7 or 8CG7? Sams has various similar chassis in sets 515, 518 and 566 - the osc tube will dictate which sams to use.

I'll have to discharge the HV to get a look inside again....all the tubes are mounted on the INSIDE of the board, facing the picture tube. Gonna be doing that shortly. I remember seeing those diodes, so I know exactly which ones they are. Connected common cathode.

The diodes I have here are 1N4001, 1N4005, 1N538 H8, and these:

http://www.mouser.com/ProductDetail/...fp8QPCBfkcQ%3d

Would any of these be suitable?

[Kamakiri]

Originally Posted by Findm-Keepm

Have you replaced the Horizontal AFC diodes? It's a dual diode pack - either common cathode, or series-connected. We replaced them with silicon switching diodes, typically 1N914 or 1N4148, available at Radio Shack, 100 for $2.

What's the osc tube, a 6CG7 or 8CG7? Sams has various similar chassis in sets 515, 518 and 566 - the osc tube will dictate which sams to use.

It's an 8CG7.

And I was wrong, they are series connected. Are these the ones we're talking about?

[DavGoodlin]

The diodes look like a three-leg black or gray lego piece with an epoxy bubble on top, one half inch log, one quarter deep and high.

I looked the chassis number and my Sams book lists set 515, which I don't have.

[Kamakiri]

Okay, yeah, I see it now......