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- Early B&W and Projection TV (http://www.videokarma.org/forumdisplay.php?f=19)

- - 5pf7a (http://www.videokarma.org/showthread.php?t=274880)

https://www.ebay.com/itm/37400552784...2Cchnl%3Dmkcid

Not mine
This guy is reasonable on all his stuff

The P7 means it's NOT a white phosphor (P4) or color (P22) TV tube or a green (P1) scope tube. It's probably a radar tube...It might be useful as a test tube for a set where you want to repair it and bench test it without risking the correct CRT for the set, but there's lots of P4 test tubes out there too.

Interesting, my phosphor list has P7 as "Blue, with yellow persistence" :scratch2:

Yes, P7 is a blend of two phosphors. A short blue phosphor and a long persistence yellow. They were commonly used in radar.

Here's a very out of focus image I managed to get on a monster 12FP7 CRT.

https://live.staticflickr.com/2752/4...5099d233_z.jpg https://live.staticflickr.com/4011/4...66fb918b_z.jpg

5PF7? That doesn't seem right. I think what you may have meant is 5FP7. If there is such a CRT as a 5PF7, I've never heard of it. Another reason I think 5PF7 is a mistake is, after all, there is no such thing, that I have ever known or heard of anyway, as an "F7" phosphor which has ever been used in a cathode-ray tube, be it a TV CRT or one for radar, oscilloscopes, or any other. There could very well be or have been such a tube designed for very specialized video applications but, as I said, if there is, a 5PF7 is definitely a new one on me. If this is in fact a special-purpose tube, finding a replacement for it could be very difficult if not downright impossible.

BTW, I cannot imagine how or why that image you posted is so far out of focus. If the CRT is in fact designed for use in television receivers, the focus control must be very far off (turned to one extreme or the other of its rotation), or else something is very seriously wrong with the focus circuit in the TV set itself. Did you check the set's focus rectifier tube (1V2, 2AV2, etc.) and replace it with a known good tube? If this tube is defective or even just weak, it can throw the focus off by quite a bit.

Correct 5FP7
A little dyslectic

Quote:

Originally Posted by Jeffhs (Post 3240830)

...
BTW, I cannot imagine how or why that image you posted is so far out of focus. If the CRT is in fact designed for use in television receivers, the focus control must be very far off (turned to one extreme or the other of its rotation), or else something is very seriously wrong with the focus circuit in the TV set itself. Did you check the set's focus rectifier tube (1V2, 2AV2, etc.) and replace it with a known good tube? If this tube is defective or even just weak, it can throw the focus off by quite a bit.

No, it's a radar CRT not meant for use in any television. The base pinout is the same as a 7JP4 but it has an additional acceleration anode on the side. I hacked it into a Motorola VT71 just to see if I could get anything on the screen.

I have a couple of 5FP7s. They have an octal base and the HV connector on the cone has a pin in its center. Some day, it could be fun to see what I can make them do. I would need matching yokes at least (they may take 10BP4-type yokes if I am lucky).