Old Muntz TV for sale Locally to me, Should I pick it up?

[vortalexfan]

Originally Posted by Electronic M

I'd be inclined to think the yoke mounting if bolted to the chassis is too far forward... maybe if you loosten the bolts slide it back a bit and re tighten the CRT will fill out while mounted where it will fit the cabinet.

Yes the yoke is fastened to the cabinet, but I think its riveted to the cabinet with 3 wing nuts on top of the yoke assembly that allow for the yoke to move fore and aft and side to side.

When I try to adjust the fore and aft yoke adjustments it doesn't move very far forward and it doesn't move very far back either because the focus magnet is in the way going backwards and the bell of the picture tube is in the way going forwards even though there's plenty of room for forward and backward movement of the yoke.

[vortalexfan]

Well I got it figured out, I ended up having to completely remove the yoke and the focus coil off the picture tube neck and chassis and reset everything including the picture tube position and now its working as it should.

[vortalexfan]

OK so here's how it looks so far, see picture below.

I think the IF and the Tuner still needs alignment because Channel 3 is showing up on where Channel 6 should be on the tuner and channel 4 is showing up where channel 5 should be.

Its also having issues with retrace lines going across the screen that will only go away if the screen's brightness and contrast controls are tuned way down to the point that the screen is barely visible, and I know I've had the screen brighter than this without retrace lines, so I think the IF and the tuner alignment is still screwed up somehow.

I can't figure out a way to do the alignment without having to take the TV chassis out of the cabinet so I can see what the screen looks like when I'm tweaking the IF and tuner alignment controls but I need to have the TV in the cabinet so I can see what the tuner knob's position is at in reference to the channel selector escutcheon.

Any ideas as to what I could do, and no I don't have a signal generator that I can use for the alignment process.

[electronjohn]

Prop a mirror up in front of the cabinet and have at it...just like the olden days

[old_coot88]

What make you believe retrace lines are IF/tuner related? Hopefully you're not contemplating twiddling the IFs.

[Tube TV]

I wouldn't want to mess around with the IF cans if I didn't have to.
And I didn't have a alignment generator.
Been there, done that back in my early teens. Trust me, don't do it.
It's tough to get back correctly

I'd be looking more in the horizontal oscillator , sync, video output.

It's good to see you got a picture. I've got some reading to do.
The last time I had time to check in it was still cooking 5u4's

[vortalexfan]

Originally Posted by old_coot88

What make you believe retrace lines are IF/tuner related? Hopefully you're not contemplating twiddling the IFs.

I've already had to twiddle the IF adjustments, because right after I straightened out the power supply issue I was having issues with the video so I had to monkey with the Video and Audio IF adjustments in order for the TV to produce a useable picture when I had a signal source hooked up to it.

For a while when I adjusted the IF adjustments the retrace lines went away and also the picture brightened up as well but then I had some issues with the tuner where the fine tuning knob wasn't working right so I readjusted the video and audio IF coils again and was able to get the fine tuning knob to work like it was supposed to but then the retrace lines reappeared and the channels aren't in the right spot on the tuner in reference to the tuner channel indicator bezel.

That's why I think the retrace lines are IF related.

[vortalexfan]

Originally Posted by Tube TV

I wouldn't want to mess around with the IF cans if I didn't have to.
And I didn't have a alignment generator.
Been there, done that back in my early teens. Trust me, don't do it.
It's tough to get back correctly

I'd be looking more in the horizontal oscillator , sync, video output.

It's good to see you got a picture. I've got some reading to do.
The last time I had time to check in it was still cooking 5u4's

Well the 5U4 tube being cooked was due to an improperly installed electrolytic cap in the focus coil circuit.

This TV uses coils for the IF rather than cans. And I've already had to tweak them because after I got the power supply issue straightened out the TV had video issues where it wasn't producing a proper picture with a signal source hooked up.

[Electronic M]

Yeah.... unless you have a TV sweep/marker generator and an oscilloscope and a bit of practice on a set you don't care about you should NEVER touch video IF adjustments in a TV.... Advice I've give everyone who mentions wanting to adjust IF.

Audio isn't hard to fudge a proper adjustment by ear, but video isn't something anyone is likely to get right without instruments.

[vortalexfan]

Originally Posted by Electronic M

Yeah.... unless you have a TV sweep/marker generator and an oscilloscope and a bit of practice on a set you don't care about you should NEVER touch video IF adjustments in a TV.... Advice I've give everyone who mentions wanting to adjust IF.

Audio isn't hard to fudge a proper adjustment by ear, but video isn't something anyone is likely to get right without instruments.

Well unfortunately the video IF was already screwed up on this thing before I even touched it, as all three Video IF Coils adjustments were backed out to the point that they were almost completely out of their cores, so my fiddling with it really didn't make it much worse than it already was.

So unfortunately this TV (unless someone can loan me the right tools to do it right) may just never work correctly like it did when it was brand new.

[Kevin Kuehn]

I think what you're dealing with is a CRT that's seen it's better days. I don't see that this set has any vertical retrace blanking circuitry, so pushing the brightness up will only irritate the retrace line issue. The channels being off can only be corrected in the tuner, not the video IF. The whole Video IF can be shifted slightly and it would only affect the picture and sound response, it's in no way capable of moving individual channels to new locations. Are you 100 percent sure your home brew dial indicator has the channels in the correct locations? Some tuners have an individual oscillator slug for each channel, however Sams 101-5 mentions bending the coils to align this TV's tuner channels. I really would not recommend you go there without having the proper equipment.

[vortalexfan]

Originally Posted by Kevin Kuehn

I think what you're dealing with is a CRT that's seen it's better days. I don't see that this set has any vertical retrace blanking circuitry, so pushing the brightness up will only irritate the retrace line issue. The channels being off can only be corrected in the tuner, not the video IF. The whole Video IF can be shifted slightly and it would only affect the picture and sound response, it's in no way capable of moving individual channels to new locations. Are you 100 percent sure your home brew dial indicator has the channels in the correct locations?

Well I don't think there's anything wrong with the picture tube because I have managed to get a nice bright picture out of it before that didn't have retrace lines in it (just look at some of my previous posts).

As for the tuner escutcheon goes, all I had to go by was a very poorly shot picture of a tv just like mine that someone on here had picked up a few years back and posted about on here, and from what I was able to make out in the picture, the position of the numbers on my dial are just like on the original.

[Kevin Kuehn]

I can tell from your last picture that the video frequency response is not that terrible, which indicates the IF alignment isn't too far out. There could possibly be something messing with the overall gain, but I doubt it's alignment. Since you've already done so I guess you can justify that you've nothing to loose by further fiddling with it. What others are warning of is that there's no proven method to the madness in doing things that way. I suppose if you happen to have a photographic memory you would stand a better chance.

[vortalexfan]

Originally Posted by Kevin Kuehn

I can tell from your last picture that the video frequency response is not that terrible, which indicates the IF alignment isn't too far out. There could possibly be something messing with the overall gain, but I doubt it's alignment. Since you've already done so I guess you can justify that you've nothing to loose by further fiddling with it. What others are warning of is that there's no proven method to the madness in doing things that way. I suppose if you happen to have a photographic memory you would stand a better chance.

Well actually I am very good at remembering things especially if it's useless information (such as the year a classical composer was born and when they died, electronic and computer repair information, etc.)

Anyways I do know that when I got this TV all three of the Video IF adjustment coil slugs were backed out pretty far which tells me that there was video problems with this TV previously and someone tried to fix it by turning those IF adjustments and apparently it didn't fix it so that was why the TV was taken out of service.

And I'm going to try and see if I can adjust the tuner. If it doesn't adjust to where the position should be on the tuner dial bezel, then I'm going to say that the bezel is incorrect.

[old_coot88]

Well since the ship's already sailed, no choice now but to forge ahead.

A few years ago on here there was a lengthly thread by a Noobie who restored his grandparents' heirloom DuMont. Turns out the Grandad had screwed with all the video IFs, and the grandson, without any instrumentation at all, eyeball-aligned it back into showing a near-perfect picture. Just took enough time, determination and patience. Germane part of the resto saga begins with post # 101 --

http://www.videokarma.org/showthread...ignment&page=7