CRT experts please

[radio nut]

The uncoated crt is weak and has the tv station test patterned burned into the screen. So I will keep it for the set that needs one in order to run. The crt I put in tested 800 or so on my B&K (before I broke the meter on it!!!). The picture is sooooo much better now! I am thinking about posting all of the final pictures here soon. Oh and yes someone did say to use slip plate from grainger for the aquadag. I drive past there on my way to work so I will give it a shot.

[dieseljeep]

[QUOTE=radio nut;3053511]I """think"""" 500uuf......

Could Muntz for this set have ordered uncoated crt's?
I am very sure that the diagram does NOT show a line from the crt coating to ground.

But It calls for a 16rp4 crt.

I have a 20" Muntz, where the CRT was necked. I removed the broken CRT and trashcanned it. I don't remember seing a aquadag coating on it. I also remember seeing other Muntz's without it as well.
The tube had a rubber stamping stating: American Television, Chicago,Il.
IIRC, Those CRT's, had a slightly bluish white phosphor, when compared to other sets next to it.

[wa2ise]

On a CRT with missing 'dag, would using aluminum foil glued to the outside where the 'dag should be work? Of course such foil would be grounded.

[radio nut]

[QUOTE=dieseljeep;3053944]

Originally Posted by radio nut

I """think"""" 500uuf......

Could Muntz for this set have ordered uncoated crt's?
I am very sure that the diagram does NOT show a line from the crt coating to ground.

But It calls for a 16rp4 crt.

I have a 20" Muntz, where the CRT was necked. I removed the broken CRT and trashcanned it. I don't remember seing a aquadag coating on it. I also remember seeing other Muntz's without it as well.
The tube had a rubber stamping stating: American Television, Chicago,Il.
IIRC, Those CRT's, had a slightly bluish white phosphor, when compared to other sets next to it.

The original crt had american television on it also...But It had to be cheaply made, the phosphor did not even cover the entire front screen area . on the top right side there is a section about one quarter of an inch tall that is uncoated

[bandersen]

Originally Posted by wa2ise

On a CRT with missing 'dag, would using aluminum foil glued to the outside where the 'dag should be work? Of course such foil would be grounded.

Sure, I've done that a few times

[josephdaniel]

Could you post a picture of the burn in if you can photograph it sounds like it would lok kinda neat.

[radio nut]

Originally Posted by josephdaniel

Could you post a picture of the burn in if you can photograph it sounds like it would lok kinda neat.

I will give it a shot......will not be til sunday "probably" I agree that would be kinda cool to post it. I believe it is the classic"indian" test pattern.....
would be cool to find out that I am wrong and have someone post the correct pattern

[snelson903]

Originally Posted by Phil Nelson

Another good product for replacing aquadag is Aerodag G. Easy to spray on, and it dries in a few minutes.

Phil Nelson

where can you buy aerodag ,and how is it made conductive, tell me more if you have the info im interested.

[radio nut]

I need to add that Stromberg6 was also right.... He pulled up the specs for this crt and he did state that it called for a coating to be in place.

[earlyfilm]

Originally Posted by radio nut

. . . . . . . . . . .Yes there is a high voltage cap below the high v rectifier . . . . . . . . .

The most common basic 1951 Muntz chassis was used in set model M31 and a bunch of other adjacent numbers indicating cabinet variations . The M31 schematic in Beitman's 1951 page 101 does NOT show a 500mmF underneath the 1B3, but it does show an aquadag coating on the CRT. To lessen horizontal streaking on a CRT one needs some HV capacitance. This could be either an early repairman's fix or a factory modification to use some 16DP4A's that Muntz or the repairman happened to have.

When one looks at the three alternate CRTs used with this chassis, one will see both the 19DP4A and 16RP4A carry an aquadag coating while the 16DP4A has no aquadag! So, this chassis could be a production line substitution where Muntz used a different CRT that they purchased for a few cents less than the cost of a 500mmF doorknob, or it could be just a serviceman's replacement CRT because he could not quickly locate a correct tube.

Jas.

[bandersen]

Originally Posted by snelson903

where can you buy aerodag ,and how is it made conductive, tell me more if you have the info im interested.

I got mine from Ted Pella, Inc. http://www.tedpella.com/semmisc_html...#anchor1349940

It's finely powdered graphite, which is conductive, mixed with is some aerosol bonding agent. I've also used SlipPlate and think it's easier to work with because it produces a thicker, tougher surface.