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

[Electronic M]

Originally Posted by vortalexfan

OK so a little update, I dug out an old B & K Precision DynaJet 666/606 Tube Tester that a friend of mine gave me and I used that to test some of my tubes in my TV including my 1B3GT tubes.
Apparently the most crustiest nastiest looking 1B3GT tube I had in my tube stash which was a Sylvania 1B3GT tube turned out to be the best 1B3GT Tube I had in my stash and all the other ones (including the one that was in the TV when I got it that was marked "VEE" on it that I thought was actually the best tube of them all) turned out to be bad.
The B & K DynaJet 666/606 Tube tester puts a load on the tubes as if they are in circuit when testing the tubes so you get a real world test result as to whether or not the tube is actually good or not so the test results are more accurate.

The interesting thing is that the B & K Tube tester tested the crusty looking 1B3 tube as being almost NOS in the Quality Test and the Grid Emissions test showed no Deflection at all, and the other 3 tubes that my Sencore tube tester tested as "good" the B & K tester tested them as bad including the 1B3 tube that was marked "VEE" on the base (which the Sencore tester tested it as almost NOS).

So it seems I may have found my new go to tube tester...

Also when I put the Sylvania 1B3 tube into the TV the screen's brightness and contrast improved greatly and is now even brighter than it was previously and the weird focus issues that were going on with the contrast and brightness controls being rotated cleared up significantly as well.

I still need to adjust the vertical and horizontal size and linearity yet but I think Its definitely an improvement over what it was previously.

See picture below for what the picture looks like now with the good 1B3 tube in it.

Pix looks a bit washed out and it looks like neck shadow is bugging you but otherwise not bad.

As a fellow B&K 606 owner (of roughly 17 years) I can tell you it is a good tester, and also tell you that no tester will give comprehensive real use case testing of HV rectifiers and sweep tubes....it makes a good guide to what is not worth installing but sometimes actually swapping tubes is the only way to find one the set likes.

One small nit to pick: you called the face mask for the CRT a shadow mask... that is incorrect. A shadow mask is a screen mesh found only inside the glass envelope of color CRTs. A shadow mask is placed roughly 1" behind the phosphor such that the electron gun beams must pass through its holes to hit and illuminate the phosphor....the shadow of the shadow mask prevents the beams from landing on the wrong color dots and in unphosphored screen area. You will never see a shadow mask in person unless you smash a hole in the glass of a color CRT.

[vortalexfan]

Originally Posted by Electronic M

Pix looks a bit washed out and it looks like neck shadow is bugging you but otherwise not bad.

As a fellow B&K 606 owner (of roughly 17 years) I can tell you it is a good tester, and also tell you that no tester will give comprehensive real use case testing of HV rectifiers and sweep tubes....it makes a good guide to what is not worth installing but sometimes actually swapping tubes is the only way to find one the set likes.

One small nit to pick: you called the face mask for the CRT a shadow mask... that is incorrect. A shadow mask is a screen mesh found only inside the glass envelope of color CRTs. A shadow mask is placed roughly 1" behind the phosphor such that the electron gun beams must pass through its holes to hit and illuminate the phosphor....the shadow of the shadow mask prevents the beams from landing on the wrong color dots and in unphosphored screen area. You will never see a shadow mask in person unless you smash a hole in the glass of a color CRT.

Yeah, I kind of forgot about that. Anyways yes I think once I get the neck shadow and the vertical and horizontal size and linearity adjusted it should be good.

[Electronic M]

BTW if sockets 1 and 2 on your B&k 606 are still okay (not making flakey contact with the tube ) you should probably track down a set of socket savers while it is still good.

[vortalexfan]

Originally Posted by Electronic M

BTW if sockets 1 and 2 on your B&k 606 are still okay (not making flakey contact with the tube ) you should probably track down a set of socket savers while it is still good.

They're still making good contact yet.
I'll check into getting some socket savers for them, I believe they sell some at AES for a few bucks.

[vortalexfan]

OK so here's where I'm at currently with the TV.

As you can see I still can't seem to get the neck shadow to go away completely but the screen looks much less washed out looking, much brighter, and more clearer looking than it did.

The IF section needs touching up some more as well as the audio is really noisy when certain screens come up.

See Picture below.

[vortalexfan]

OK so I'm working on trying to get the picture so its better centered again and so that the picture fits within the pitcure tube mask which I basically took the mask out of the front of the cabinet and taped it to the picture tube so I could get an idea of how the picture should look and I'm still not having much luck getting the picture to center properly in the picture tube and mask.
I'm still having problems with the neck shadowing issue and can't get the neck shadow to go away.

Does anyone have a picture of a correctly adjusted round picture tube so I can see what it should look like properly adjusted?

Also I'm having problems with the HV Rectifier tube's anode cap breaking off the anode lead for the HV rectifier tube, and no matter how I solder it on it keeps getting bent to the point that the wire just snaps off the anode cap.
Its just a metal spring clip by the way which doesn't seem like a good design, especially in that application.

Anyone have a fix for that?

[vortalexfan]

OK Well I finally got the picture fixed on this thing, but now I can't get the darn chassis back into the cabinet.
For some reason or another the vertical output transformer mount keeps catching on one of the vent holes on the bottom of the cabinet.
No matter how many different ways I try to insert the chassis into the cabinet I still end up with the vertical output transformer mount snagging on one of the vent holes on the bottom of the cabinet and because of that I can't get the chassis to sit right in the cabinet in order to line up with the mask and the knobs to line up with the holes they go into.

Does anyone have a better way of installing the TV into the cabinet so that I don't have to worry about the darn vertical output transformer snagging on the cabinet?

[Kevin Kuehn]

Maybe a thin layer of cardboard between the chassis and cabinet would allow you to position it easier, then when it's where it needs to be remove the cardboard. I don't quite follow how it's possible for vertical transformer to be hanging below the chassis, unless it's an aftermarket replacement. Possibly the bottom wood is warped upward.

[Electronic M]

It might be possible to warp the chassis a bit so it don't snag. If you have a thin piece of sheet metal to cover the vents while inserting/positioning the chassis I'd use that like Kevin's cardboard idea (the transformer should not be able to gouge into metal the way it possiblily could with cardboard.

[vortalexfan]

Originally Posted by Kevin Kuehn

Maybe a thin layer of cardboard between the chassis and cabinet would allow you to position it easier, then when it's where it needs to be remove the cardboard. I don't quite follow how it's possible for vertical transformer to be hanging below the chassis, unless it's an aftermarket replacement. Possibly the bottom wood is warped upward.

Well the vertical output transformer is bent just enough that it protrudes below the bottom of the chassis and I've tried to bend it back into shape but it don't work it just bend's back.

And the mounting bracket for the vertical output transformer is also where one of the chassis mounting screws attaches to hold the chassis into the cabinet.

[vortalexfan]

Originally Posted by Electronic M

It might be possible to warp the chassis a bit so it don't snag. If you have a thin piece of sheet metal to cover the vents while inserting/positioning the chassis I'd use that like Kevin's cardboard idea (the transformer should not be able to gouge into metal the way it possiblily could with cardboard.

I've tried that, I'll get the chassis in just enough to get it lined up but then when I try to put the chassis in its final resting position the vertical output transformer snags and then the chassis pops out of position.

[Kevin Kuehn]

Is there any wiggle room in the mounting holes for the transformer bracket that would allow it to shift upward, or possibly you could drill out the holes a little more. Ideally you want to be able to fine tune the position after all the chassis screws are started. The chassis screws should act as clamps and not precision locating points.

[vortalexfan]

Originally Posted by Kevin Kuehn

Is there any wiggle room in the mounting holes for the transformer bracket that would allow it to shift upward, or possibly you could drill out the holes a little more. Ideally you want to be able to fine tune the position after all the chassis screws are started. The chassis screws should act as clamps and not precision locating points.

Well it turns out that I think what the problem is, is my picture tube.

Unfortunately I had this problem before, I had to move the picture tube forward slightly in the chassis in order for me to get the picture to fill out properly but that slight move forward of the picture tube is just enough to make it so that the chassis doesn't fit into the cabinet properly anymore.

Which is why I had to move it back to where it was before which is how I screwed up the picture the first time when I had the picture filled out like it was supposed to be, so then when I did it again this time it was the same issue.

Is it possible that this picture tube (which I suspect is a replacement) is longer than the orginal one was, so because of that it doesn't work right with this particular chassis and perhaps this TV never worked right to begin with after the picture tube was replaced?

[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.

[Kevin Kuehn]

That's a strange problem because neck shadow is usually caused by the yoke not being forward enough, relative to the CRT.