25SP22 vs. 25VERP22 and damper tubes
 

Hi all -

Question - I've got a 1967 Admiral with a 25SP22 CRT. Still looks like it has some life left in it, but has cataracts beginning about 2-3" from the edge. I've done some reading on cataract repair, but the thought of popping the safety glass off the front of an evacuated glass bomb doesn't sit too well with me just yet :no: .

I have a late 70's Zenith with a 25VERP22 tube that works well. Any chance of these two CRTs being even remotely compatible? If possible, I'd like to swap tubes to get the Admiral running and on its way to being a watcher.

Another question - the damper tube in this set is a 6CG3. The set was working well until yesterday - I heard some arcing during startup and looked at the tube. The inside looked like a miniature lightning storm, arcing for about a half second every minute or two. I removed the tube, inverted it, and tapped it a couple times. I saw some particles floating around in the tube.

After I tapped the tube, I put it back in the set and the set ran flawlessly for about a day. So - is the lightning a symptom or a result? I plan on getting another damper tube but want to make sure that there isn't anything else that should get looked at before popping it back in.

Thanks!

Jim

I've had horz outputs that did that too. Generally, when they started arcing, they were done for. AFAIK, it's just something that happens.

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Doh - I should have seen the V in the second part number. I've been searching the web trying to find CRT information and I know that has come up a couple different times.

nasadowsk - Hopefully I will have a new damper by sometime next week and will be able to see if this was just a fluke.

Thanks guys!

Jim

Jim,

I don't know where you're at, but I've got a semi-working color Admiral of similar age. Free if you want it, in the Detroit area.

Carmine -

Thanks for the offer - unfortunately I don't have room for another complete set.

Another question - how hard is it really to remove cataracts from a rectangular tube? This one isn't too bad yet; the cataracts begin at the edge and continue in about 2-3". The center of the tube is unaffected, maybe a bit hazy.

I thought about removing the tube and placing it neck-down in a sturdy 55-gallon plastic garbage can with a couple bags of cat litter or something in the bottom for stability. That part doesn't worry me too much; it's the heating and popping of the safety glass that's got me leery. I don't want to crack the face of the tube.

Anybody have any suggestions or tips/tricks to make this safer? Do you use something like leather aprons and gloves? Outdoors or indoors? Most of the instructions I've seen have been for round tubes, which I would imagine would be slightly stronger due to their construction.

Thanks for the input!

Jim

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Andy -

Thanks for the information. Another quick question about your setup though. You mention "the glass should fall off" and "cover the bell with a heavy blanket". Is the face of the tube horizontal or vertical during this process? My thought (from a couple posts ago) was to put the tube in something like a garbage can, with the face pointing up toward the ceiling.

This information has made me a little more comfortable in attempting to revive this tube - thanks again for all the help, guys!

Jim

Be sure to wear eye protection like industrial grade goggles. You don't want flying glass getting into your eyes...

and drinks lots of beer while you do it..LOL

wiseguy

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Andy -

Thanks for the clarification. This isn't seeming as daunting as it did a couple days ago. Plus, I have another set to practice on - a 1965 Admiral with a 23EGP22. Tube is nice and bright but the safety glass has come unbonded almost all the way to the middle, leaving about a 4" circle.

Based on the advice you guys have given me, that one looks a little easier, and since I got it running today, I've got a little more incentive to repair its CRT.

Thanks again to everyone who's responded - it's amazing to be able to toss a question out there and have half a dozen or so people come back with information.

Jim

That's why I read this forum almost every day. I'm sure I'll have more than a few questions when I dig into my Zenith roundie :yes:

I have done it face up in a trash can-the only drawback I can think of is that any junk particles that might be floating around inside could fall down into the gun and cause problems. The chances of that being a problem are slim, I think.

The next time I get one I'm going to put it facedown in a bathtub full of water for several days. CRTs left outside for a length of time will have the bonding material broken down naturally but I don't know how long it takes for the breakdown to occur.

Success!
 

Wow! :banana:

Got to it this weekend. Figured I'd try on one of the two Admirals that I recently picked up. This one had only about a 4" diameter circle in the center that was visible; everything else was grossly out of focus if visible at all. Even though the tube was a 23EGP22, the spot in the center looked good enough that I thought it would be worth saving.

Placed the tube in a trash can with a 30# bag of cat litter at the bottom for weight, heated the entire face slightly, then began attacking the cataract edge with the heat gun. To my surprise, it loosened up in a few seconds and literally popped free as others had suggested. I was surprised that the tube face was quite cool to the touch even after the process - I was worried about applying too much heat to the face and cracking it.

After cleaning the tube, I used 4 cardboard spacers at the edge to give me about 1/16" clearance and glued the glass back on around the edges. Let it dry, taped it up, and put it back in the set.

Picture looks great - will post before and after shots as soon as I get the pictures out of my camera.

The bathtub idea looks interesting - possibly safer than this procedure, but I don't have any bathtubs on the first floor and would hate to have to explain to my wife why a CRT was enjoying a bubble bath in the tub. :sigh:

Thanks again for all the help, guys. I was incredibly nervous even attempting something like this, but with everyone's detailed instructions and encouragement, it went quite easily. I may even tackle the tube in my other Admiral once I get it back up and running.

Jim