Picture tube question - Videokarma.org TV - Video

damen · #1 03-17-2009, 04:45 PM

Anyone know what picture tube number a 21 inch 1954 Packard Bell model #2743 uses?

Steve K · #2 03-17-2009, 05:53 PM

21yp4

kx250rider · #3 03-17-2009, 06:54 PM

That's a DEEP tube; might be less than 70 degrees. I've seen those in Philcos. If you can't find one, most any 21" glass bakelite base tube can be used.

Charles

jeyurkon · #4 03-17-2009, 07:03 PM

Quote:

Originally Posted by kx250rider

That's a DEEP tube; might be less than 70 degrees. I've seen those in Philcos. If you can't find one, most any 21" glass bakelite base tube can be used.

Charles

My databook says 65 degrees.

John

damen · #5 03-17-2009, 07:58 PM

Will a 21fp4a work in it's work as substitute ?

jeyurkon · #6 03-17-2009, 08:25 PM

I don't see it listed as a substitute, but it seems pretty much identical. I think Charles is right about most any 21" tube and this one seems to require no changes if I read the technical data correctly.

John

bgadow · #7 03-17-2009, 09:25 PM

The YP4 was used in a lot of sets-Philco liked them, for one. They should turn up fairly often. Now, if I had an FP4 sitting here I'd go ahead and try it. It really isn't that much trouble to change the crt in sets that age. I do see a difference in my book-the FP has a cylindrical face (kinda like a Trinitron) while the YP4 has the more typical spherical face. Probably would lead to interference issues at the mask.

damen · #8 03-17-2009, 10:58 PM

Thanks guys for all your help you are greatly aprisheated

Don Lindsly · #9 03-18-2009, 01:09 AM

The 21YP4 and 21ZP4 have unique bulb dimensions. No other 21 inch tube will fit without serious mechanical changes including the mount and mask. No other tube will fit up against the mask properly.

The 21YP4 is electrostatic focus and the 21Z is magnetic. Don't be fooled into buying another tube to fit in place of either one or you will be disappointed.

jeyurkon · #10 03-18-2009, 08:49 AM

We are fortunate to have someone like Don to correct our sometimes inaccurate advice. He's absolutely correct.

I didn't realize how much of an oddball these are, especially the 21FP4, until I looked up more detailed data-sheets.

On the other hand, if you asked about the 21FP4 because you already have one you might be able to use it to see if you have the set working while you search for a 21YP4.

My statement about a deflection angle of 65 degrees wasn't quite correct either. That is the horizontal deflection angle. The diagonal deflection angle is 70 degrees for both CRTs.

John

kx250rider · #11 03-18-2009, 10:08 AM

Quote:

Originally Posted by jeyurkon

We are fortunate to have someone like Don to correct our sometimes inaccurate advice. He's absolutely correct.

I didn't realize how much of an oddball these are, especially the 21FP4, until I looked up more detailed data-sheets.

On the other hand, if you asked about the 21FP4 because you already have one you might be able to use it to see if you have the set working while you search for a 21YP4.

My statement about a deflection angle of 65 degrees wasn't quite correct either. That is the horizontal deflection angle. The diagonal deflection angle is 70 degrees for both CRTs.

John

I forgot about those cylindrical-face tubes too. Hoffman used a lot of those (21FP4?). It will leave a gap on the sides of the mask. Another one that gets me is the 20" (vs. 21") tube... You almost can't spot it unless you see the number. I got saddled with one of those from a rebuilder once, and wondered why the mounting band was so loose

... But to repeat, most any of these tubes will work, electrically.

Charles