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-   -   '47 magnavox - gutless high voltage.... (http://www.videokarma.org/showthread.php?t=144656)

Old1625 02-14-2008 07:59 AM

If the "wiggle" you mention moves along slowly in a wave action along the side of the raster then you've got some 120Hz feeding into the horizontal sweep circuit--a sure sign of a bad 'lytic somewhere in the power supply.

If the raster is narrower at the top or bottom--keystone-shaped--then the yoke is suspect.

Another member here was going around in circles over weak HT in an old Zenith, and discovered that the new flyback he put in was the cause. Swapping it out again fixed it.

nasadowsk 02-14-2008 06:47 PM

I can turn the wiggle up and down in speed by adjusting the vert hold. I think I probed all the B+ lines, but I'll check 'em again - it'd sure be nice for this to be a simple power supply issue!

No keystone, thankfully...

As far as the flyback? This one's original. Maybe it is bad, but I'm not sure of a good way to test it...

nasadowsk 02-18-2008 10:34 PM

Well...figured it out.

It's the flyback :(

What's weird is it reads open on the DMM, but it still kinda makes HV. I'm not sure how that works - maybe it arcs over?

Anyway, I'll have to hunt one down. So far, the Sam's lists the subs:

Stancor A-8117
Chicago TFB-1

FWIW, the Maggie # is 320026-1

Looks like a '630 one, but I'm sure they all did back then :/

cbenham 02-21-2008 07:19 PM

[QUOTE=nasadowsk;1663625]Well...figured it out.

It's the flyback :( So far, the Sam's lists the subs:

Stancor A-8117
Chicago TFB-1

FWIW, the Maggie # is 320026-1

It's also a Thordarson FLY-1.
The Sams sub may be wrong; my Stancor book crosses the Magnavox number to A-8127 and this matches to a Fly-1 and an RCA 211T3.

Best,
Cliff

yagosaga 02-22-2008 02:17 AM

Quote:

Originally Posted by nasadowsk (Post 1663625)
Well...figured it out.
It's the flyback :(

Are you sure?

- Eckhard

nasadowsk 02-24-2008 04:37 PM

Quote:

Originally Posted by yagosaga (Post 1670605)
Are you sure?

- Eckhard

Yeah. The open HV wnding seems to be a good hint that it's bad (I tried poking down a little, maybe I'll unwind a layer tomorrow and see if the break's on the surface...)

nasadowsk 02-24-2008 05:40 PM

Quote:

Originally Posted by yagosaga (Post 1670605)
Are you sure?

- Eckhard

Yeah. The open HV wnding seems to be a good hint that it's bad (I tried poking down a little, maybe I'll unwind a layer tomorrow and see if the break's on the surface...)


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