1953 Admiral C2226Z Restoration - Page 2 - Videokarma.org TV - Video

bandersen · #16 08-03-2016, 09:33 AM

Quote:

Originally Posted by cluelessgame

Ended up dropping $205 on a new one from Video Display Corp. (http://vdc.mybisi.com/product/21zp4) not sure if it's actually the correct tube but it has a 1 year warranty and I guess I can return it if it isn't...the product picture doesn't look anything like a 21ZP4 but I'm hoping that's just a generic stock photo. Was there ever an overlap of monochrome tube numbering?

Good luck with your purchase. I hate to say it but VDC lists many old CRT types but actually has very few (if any) in stock regardless of what their website says.

Yes, they use generic stock photos. No CRT numbers were ever reused.

cluelessgame · #17 08-03-2016, 11:02 AM

I did get an order confirmation...hopefully that means something

will try direct injection as DaveWM suggested but I'm doubtful it'll show any improvement considering the picture tube tests completely dead on my Sencore CR-31...I turn the Gun Bal up all the way in both cutoff and emission mode and the needle only moves up to just short of the gun bal line...could it be an un-welded cathode? I'm a little Hesitant to try the re-welding technique until I know for sure I have a replacement so I don't end up necking the tube and am unable to get it rebuilt at the ETF whenever they get that up and running (fingers crossed)

I've been having issues with the super mack meter, but I know at least the cutoff and emission modes work b/c other known-working tubes test good...the H-K and G1 shorts modes make the needle go negative, though I've tried removing G1 shorts as well as rejuve 1 and 2 with no flashing or improvement whatsoever

DaveWM · #18 08-03-2016, 11:15 AM

Your CRT tester says no emission whatsoever? and yet you get a bright raster.
you should try another CRT tester (or confirm the one you are using on a known good tube. You could scope the pins at the CRT and make sure you are getting a good signal. Agree with Bob, call them up, last time I tried to buy a generic TV tube was told NLA regardless of what the site says.

Electronic M · #19 08-03-2016, 01:43 PM

Have you tried the tester on a known good CRT and gotten good test results? Sadly it has long since gotten to the point in the TV radio hobby that we have to repair some of the repair equipment.

cluelessgame · #20 08-05-2016, 12:09 PM

yes, I have tried it on a known-good tube and it shows good emissions and cutoff on the tester so i've ruled the tester out

DaveWM · #21 08-05-2016, 06:49 PM

and you used the same hook up procedure? or did it have a socket when testing good on the other tube?

cluelessgame · #22 08-06-2016, 01:23 AM

the known-good tube (out of a working set) used a different socket adapter, but I've also tried the tester on two 17BP4s from other sets I've yet to restore (a Majestic 70 and a Bendix C172U) that use the same socket (#1) as the 21ZP4 and they both show good emission and cutoff

same bias setting as well

also, I think I should mention before anyone asks, I have tried touching up all of the pins with a soldering iron with no improvement