Color CRT alternate question for 1969 Zenith

[Dave Drez]

HI-

I recently picked up a worn Zenith "Bradley" from 1969 with a 16Z7C50Z chassis. The CRT in it is pretty much used up. Zenith calls for either a 25XP22 or a 25AP22 for the replacement.

I understand that electrically, most of the delta gun 25 or 23V tubes are compatible, with the major difference being the mounting method as per the
implosion protection. I missed the 25XP22 for sale at the Early TV Museum, but there are other options. Does anyone have an opinion on a possible replacement choice from the below list?

23VALP22
23VAQP22
23VATP22
23VBAP22

25AJP22
25BAP22
25UP22
25YP22
25ZP22

Thank you!

Dave

[John Adams]

IIRC, using the XP to replace an AP might require swapping the bias connections around to get a good gray scale. No big problem. Might apply to some of the other tubes you listed.

[Dave Drez]

I am asking if someone would have a data sheet on the 23VAQP22... I can't find one on the inter-web.

It appears to be a replacement for the 25GP22A although the bias settings are different. Could someone please shed some light on changing the bias on a 16Z7C50Z chassis. Would that be the horizontal efficiency coil or the HV adjustment?

Thanks,

Dave

[bhegges]

I recently replaced a 25xp22 with a Zenith 23vcmp22 which I got from the ETF. Other than bending very slightly the 4 metal corner brackets to fit tight to the tube it installed just fine. I am intrigued about the bias question, my gray scale is rather blue, I figured it just needs further adjustment.

I also would like to find data sheets on these CRTs to help answer our questions.

[Electronic M]

Your grayscale appears to be mostly off due to screen adjustments. To set screens turn brightness to min, flip service switch to collapse vertical, turn screens down to extinguish line, turn red up till dim line appears, turn green up till line becomes yellow, turn blue up till you get white. Takes some practice to get correct yellow and correct white. I redid grayscale on my first deltagun set several times before I was happy.

[zeno]

Most delta guns are electrically the same. The only thing
that differs as a rule is the HV. Over the years it went form apx
< 25 KK to a little over 30KV The other major change was to black
matrix Zenith "Chromacolor"' "Super Chromacolor" and " Chromacolor 2".
Any from the 25AP & XP on can be used as a test jig for any D gun
set as long as you keep the HV in mind.
Zenith built CC tube replacements for the AP & XP but I dont remember the numbers. I even put on in my parents Y line Zenith. Z line was the
year things started changes fast. Transistors were taking over.

73 Zeno
LFOD !

[John Adams]

I do not think any parts replacements are necessary for bias adjustment. I have read about this for older 21” sets also. Especially if going from a non rare earth to a newer rare earth phosphor tube. Reason was to get the gray scale tracking correct. I think that would apply to the post above where there was too much blue.