You are probably ok if you had all the High voltage shields in place. I was working on a GE set once with the HV cage removed. It gave me a really bad headache at first. Never did that again.

---

Check out this site for the government's take on TV X-ray emissions:

US FDA/CDRH: CDRH Consumer Information - We Want You to Know About Television Radiation
Address:http://www.fda.gov/cdrh/consumer/TVRad.html

-Steve D.

Hi Guys.
Sorry, But I do not understand this thread. Are you guys joking around?
Why would someone turn the high voltage up all the way on a vintage color set?
The high voltage should not be set over 25 kv on any round color crt made in the 60's and If the crt is something like a 21axp from the 50's it should not be set over 22 kv.if I recall correctly. Please be careful.
Ed

No Joke Here
 

ED............When I first got the 21CT55 activated over a year ago, I had no way of setting the Ultor HV without a HV probe on my VTVM. I assumed the RCA engineers designed the HV portion of the CTC2B chassis to limit the HV control range to max spec for the 21AXP22 crt, somewhat above the 25KV recommended in the service manuals.Typical of my approach to design, I went for the max and left it there. Since I converted to the 21FBP22 in "64, rated at 27.5K to increase brightness, I saw no reason not to continue operating at max HV. The focus was in range and I got good convergence. Hey, it made great pictures didn't it?

Only last week when I hobbled-up a 100 to 1 HV probe and carefully calibrated it was I horrified to read 34KV Ultor or 6.5KV above RCA max spec! I immediately reduced the HV to 25KV and the screen looked terrible. I got it refocused but the convergence was way off. I then set HV to 28KV and the picture was somewhat better but convergence was still bad. Rather than getting into re convergence I simply returned HV to 34KV and posted this thread to get some expert advice. Maybe my junky HV probe is way off, but until I get a reading from a known commercial HV voltmeter I'm not going to go off screaming and mess up something that's working exceptionally well for over a year...Tom

Hi Tom
Your set does have a exceptional picture and I am sorry if I sounded insulting.
It is just so dangerous running a vintage tv set with the hi voltage set to high. Why mess around with x rays if you don't have to.
Also I take it that you have not had any problems with the crt arcing inside the neck?
When you find a probe and get the time, Set the hv to 25 kv with a black screen and re converge the crt. Vintage tv repair/collectors are hard to find.
Ed

We now have a middle of the run example of the 21CT55. Was under RCA Service Company Contract till the end of the real RCA. Still in excellent operating order. Use it once or twice a week with a Zenith DTV converter box, makes very nice pictures. Not quite to your level but very nice. Very fine CRT, a new rebuilt Colorama from 1967. Was an East Tennessee set from new, a White Lily Flour Executive here in Knoxville, TN bought it new and it was his main set until he died in 1999. His daughter gave it to us afterwards knowing we would keep it maintained and occasionally used. Console cabinet also is nice unrestored original. Sold new at Proffitt's Department Stores new in Knoxville. Area department store founded in Maryville, TN (I remember them back in the day and my mom and grandmother knew D.W. Proffitt, it's founder).

---

AK's 21CT55 Survivors
 

Kent T and Dave A joined the short list of professed 21CT55 "caretakers" which include John T, Steve K, Bob G, Tom S and Steve M, the one at the Early TV Museum? All have already or are about to completely restore these rare RCA second production models to original condition, operating to original RCA specification. The obvious exception is Tom S since I have no intentions of restoring mine to original. I have no cabinet or 21AXP22 CRT, only the front panel, the CTC2B chassis and two 21FBP22 CRTs.

I decided in October 2007 to reactivate the beast after 40 years in attic storage and use it as a test bed to determine and demonstrate in photos, the picture quality this 55 year old RCA 2CT2B chassis was capable of producing. As such, it was not constrained to replicate the original circuitry in every detail or even operate to the '55 RCA spec. I jacked up the +400v B++ supply to above +420v with silicon diodes and got a horz boost of almost 1KV. I intend to start reducing the CRT Ultar HV from its present 34KV to the 28KV range while doing a full convergence at each reduction level to determine if I loose ANY picture quality.

Since I'm ruining the 21CT55 as a composite monitor, I disabled all the tuner, RK/IF and audio portions and opened all unnecessary tube 6.3v heater strings to allow the power transformer to run much cooler. I left all inactive tubes in their sockets and documented all changes for immediate reactivation. Yes, I brutalized this valuable historical item but there are at least five other 21CT55 restorations on this forum alone. I believe I've succeeded in my goal of demonstrating the 21CT55's ability of displaying exceptional picture quality.

http://s677.photobucket.com/albums/v...0TV/?start=all[/

I do intend to refinish the surviving front panel of the original cabinet using the approach described by Bob G in his impressive restoration. I might even attempt to construct a pseudo pencil-box control panel. Tom

I guess I should jump in here with my 21CT55. It is on Steve's list but not identified as mine. Steve, permission granted.

And pix will follow. Serial #BB8801607.

I picked it up about 6 years ago at Rochester from a guy that walked up to me and asked if I wanted to buy an old color tv. Sure I said. I took a trip to his house and there it was...running. Sold for $300. I got it home and was amazed at the picture. It was soaking in color, good registration, and good convergence. The CRT is strong and original. He said it came from the home of the local RCA distributor.

But something was wrong. The color was not quite right. Turn out that either the I or Q was missing. I forget which. The pic was very orangeish. And the recap was needed.

It sat for a while in line for work. From there it took a loooong road trip to Chuck A, John Folsom and some Pony Express help from Cliff Benham. Caps, chokes, etc. done. No room here at the house for a real shop. When I gave it to Chuck, I pulled the magnet, purity ring, and yoke so he could use the yoke. I marked all of the positions on the tube neck with a Sharpie. On re-assembly, it came back as close as anyone could wish for.

On the return it had to go to storage with the cabinet as my work for the World Champion Phillies got in the way.

I retrieved it about a month ago and put it in the living room for assembly. When I did get it back in place, it worked! But it is in need of adjustment from all the changes. I can get a pic but the horizontal is slightly off and not stable. The red seems low and I have to go after that. HV is rock stable and no blooming in sight. A new problem jumped up a few days ago. On power up, the pic is good for a bit and then drops to a smear of video.

Nothing is easy about this but it lives next to my CT100 (currently at Pete Dexnis for work and comparison for his efforts) and my Philco TV123 that needs two doorknob caps. A lot of history in my living room. And a lot of furniture to walk around.

I thought I had some pix from the arrival but I cannot find them in this computer. I will try to edit this post to show the current condition such as it is.

Another survivor,

Dave A

Dave, you are blessed...I am particularly envious of the Philco. I'd rather have one than a CT100, believe it or not.

Bryan,

The TV-123 saga is the best story of the bunch. Of the six listed on Steve's site, I have had possesion of three of them. There are one or two others suspected to exist but no one can confirm them.

My first came from a retired Philco engineer who sold me a CT100 ten years ago. It was rough and I kept the chassis, CRT and sold the cabinet...the one that ended up missing at the refinishers as I remember from previous posts. He also had a 123 on his sun porch which was a greenhouse for his orchids. Whatta veneer wreck. I pulled the chassis and still have it for parts. The cabinet was beyond saving with the dampness on the porch. I took it out of charity and did not know what I had. Set #1.

Another local RCA engineer was selling his and I got it about 5 years ago. He had worked for Philco early on and got it there. He had a spare chassis also that is not included in Steve's count. The chassis' were different in that one had a beefed up rectifier on a add-on chassis. This set went to another AK collector. Set #2.

I sent that one on and it was replaced by the 123 that Chuck A documented a while back on AK. It had been a prize on a national game show and was/is in great condition. Chuck did the recap and it now awaits two small doorknobs. The big one failed and that was replaced. Now one of the others is gone and I need to get both to do it right. Any doorknob collectors out there?

It is a cantankerous beast and very hard to set gains/backgrounds to get a good pic. Set #3.

The odd thing about my 21CT55 is my mindset about it when it came back. I just threw it together and powered up and it worked. It was no different to me than a CTC7 in my mind. Just another 21" color set when you look at it from the front. I had to step back and remind myself that this is a jeeped-up CT100 and should need tender loving care to do anything at all. It lit up and now I have some work to finish. I would be curious to see how this second generation fits in with Pete's efforts on V1.0. No pressure Pete!

Stay tuned and if you are near SE PA, stop in for the tour.

I want to thank Dave A for allowing me to be the new custodian of his excess Philco 123. It is a bit scruffy, but it came with a spare chassis, so I am very much looking forward to restoring it.... one of these days.

Hey John Folsom: sounds just like a certain CT-100 in France, oui?

What is it with these rare Philco's? None of them glow properly. I've been sitting on a set of restoration caps since September 2005...

Don't know how Tom's thread got on the TV-123, but they are different in that there's not much RCA influence when you check the schematic. Also, the shallow chassis is a pain to work on; just ask Chuck. Nice nonetheless to have one. BTW, as the caretakers know, TV-123 is the chassis designation; 22D5102 is the model number of the most prolific unit, a VHF-UHF mahogany model.

21CT55 Stability Time
 

My reactivated 21CT55 has been operational for over 18 months with no problems except.......it takes about 30 minutes for the screen to reach acceptable size and convergence after cold morning power start up. It takes an additional 60 minutes to reach near perfect vertical linearity and final convergence suitable for critical picture capture.

I use the Digital Video Essentials' crosshatch with circles pattern to evaluate this problem with black felt pen dots on the CRT screen after the sets been running about three hours. The dots give a very good indication of circle size and linearity. A few pen lines indicate where convergence is less then perfect. Results have been consistent the last three mornings so what components has a 90 minute thermal time constant? I've already replaced the tubes and at least five capacitors in the vertical osc/amp circuitry and always keep the B++ buss set for 410v with my AC input Powerstat. Boost stays at +880v and the ultor runs about 30KV.

Hey, I'm not overly concerned and can live with the long warm up. It's not a
restored show item, just a hobby toy. Any comment or suggested fix is welcomed......Tom

Might want to check for wandering resistors. I've had a few sets that had vertical problems similar to yours, I've also had some that creep in as the set warms up. Use some freeze spray on suspect resistors and caps after the 90 min. warm-up, watch for a fast change in the picture where your dots are. Good luck with her, you have a great set!

Hey Tom,

I am having similar issues on my 55'. Warm up is slow. By that I mean from a cold dead start, convergence is WAY out, by about 1/2". As the voltages stabilize, convergence comes in very nicely. It takes a good 15 minutes from cold. Shut it down for a minute and you are back to way out again, but will come back into coinvergence faster if the set has been previously warmed up.

My linearity is very good, and HV regulates nicely at the 25KV spec. I too am running on a variac, at around 110vac, which gives me a spot on 400vdc B+ If I run off of 120 line voltage I get 437 vdc B+ and my flyback runs 20 degrees hotter. I already toasted the origanal, so I am being most carefull to not destroy this one. Running at 400vdc the flyback operates at about 125 degrees F after several hours of run time and also with the dog house panels removed. After I have the thing running to my satisfaction, I will reinstall the dog house panels and install a muffin fan to keep the dog house internals cool.

I would be interested in knowing what your flyback temp is after you run for several hours, just for comparison sake. I use a DMM with a thermister probe to take temp readings. I of course do it with the set turned off and the door knobs discharged. I place the probe on the surface of the primary windings and hold it there till the temp reading stabilizes. I like 125 degrees F. It seems to me to be a safe operating temp.

Been trying to run down an intermitant flashing brightness issue, but haven't had much time to trouble shoot lately. I am pretty sure if I stick at it long enough I will locate the gremlins. that is, if I live long enough :-)

I like Mark's suggestion to try freeze spray on resistors to see if I can cause the convergence to drift out. Maybe I can find a resistor that is overheating and changing value as the set warms up. Being as convergence is done with the set warmed up, it would be logical that when the set cools down it would be out of convergence if a resistor is changing value as it heat up. I just ordered up 3 cans of freeze spray. I found it online for only 4.99/can at http://www.southernhillscomputer.com/index.html some places wanted $10 per can. The stuff is R134a refrigerant. I am epa licensed to do refrigeration repair and buy this stuff in 30 pound drums normally for repairing air conditioning systems, but 30 pound drums are a bit to large for squirting resistors with :-)

Bob

Have you replaced the selenium rectifiers and checked all the filter caps? Although I haven't personally had trouble with those huge seleniums in the CT-100/21CT55, I know they're capable of trouble like you're having. Fairly simple power supply. However, it might be a benefit to have that ultra-slow warmup... I think most failures of other parts happen on startup surge; when the B+ is highest (in solid state rectified sets like this), and the tube filaments are still cold and the power supply is running hog-wild unloaded. Come to think of it, maybe let it be, as long as it isn't a slow-forming filter cap which may be pulling a ton of current. An AC ammeter would check that too.

Charles

Yep, power supply is all reworked. Seleniums are just ther for show now. Every can in the set has been re-stuffed with bran new axial lead caps.

I have monitored voltages during the warm up, but I do not find any significant variation during the period that it takes the convergence to stabilize.

Steve Kissinger saw it and said the he dosent have this symptom on his recapped 55' . I could live with it but it is a symptom I don't like when I wish to turn the set on for a few minutes to demo it to someone. It would be nice for convergence to come up right away so the picture would be watchable in a reasonable amount of time.

I even re-hooked up the old seleniums just to see what would happen. I got a very substandard 372vdc when opperating at 120vac line. The set runs much better on the silicon diodes, so I am convinced that the old seleniums cause sub par performance.

Bob

Possible 21CT55 Warmup Fix?
 

Thanks for the replies regarding my warm up problem. I've been running silicon diodes in place of the seleniums from the first time I fired up the 55 and got only 390v of B++. Lost a lot of heat in the bargain. I replaced the rectifier’s 80uf big can electrolytic with a 100uf at 475v. The B++ goes to 455v at turn on and settles back to 410V operating. A Powerstat manually keeps the AC at 113vac resulting in a B++ of 410v which produces exactly +900v of boost and 30kv of ultor.

Since the boost voltage is used in the vertical oscillator height control, any change in boost voltage or the resistancs of the 2.5meg height control, both height and linearity greatly effects screen's appearance but more importantly vertical convergence accuracy! The height and linearity are both controlled with a cheap open terminal dual pot. The 5k linearity portion was open originally and I replaced it with a single pot mounted in a new control panel hole. When I hit the surviving height pot with Quick Freeze, it collapsed the vertical screen and destroyed vertical hold. As it dried out the screen circle almost returned to normal. I replaced it with a sealed military grade Allen Bradly 2.5meg pot I had from the ‘50s. When I adjusted it to the circle dots, linearity was restored and convergence improved significantly. Was this the fix? Time will tell when I fire the 55 tomorrow morning. All Hail Marys are welcomed.

I started using Quick Freeze on the rest of the vertical circuit resistors and caps but didn't finish yet since I was running my last can out. No further temp sensitivity so far. I took Bob’s suggestion and ordered five cans for the same $12 shipping as three, from Southern Hills. My nearest electronics store was a long trip and they wanted $8 a can. Santa Ynez is great to live in but major stores are at least 60 miles RT in any direction. ....Tom

Glad you're getting close, let us know how she runs tomorrow! That dang freeze spray has found many a gremlin for me. Good stuff.......

21CT55 Vertical Warm-up
 

The replacement of the height pot and .047uf amp feedback cap made a major improvement in vertical height and linearity stability. The sequential pictures show the cross hatch and circle pattern improving during warm up. Although better, it is still entirely too long a time for performance demonstration.
The black felt pen dots applied directly to the CRT screen represents the ideal circle locations and are very useful in judging the results of any circuit modification. My 55 can be expected to present a useful screen for casual viewing in about 10min after turn-on and reach maximum picture quality for critical screen shots in about 1hr. Convergence has not been optimized since vertical performance is the issue here.

Is my 55 unique with this problem or do all CTC2B chassis and maybe all RCA CTVs up thru CTC10 have this same problem to some extent? I would like to see sequential screen shots of member's early RCA's during warm-up. Ideally they would use the same DVE DVD cross hatch and circle pattern I use, and would apply the felt pen dots directly to the CRT glass for reference.....Tom

21CT55 Warn-up
 

Bob G........Somehow I didn't realize you were the "Bob" of the recent, most impressive full restoration of all 21CT55s. Since you did a complete recap I would expect yours to have the least problem with warm-up drift. I assume you Quick Freeze'd all resistors in both deflection systems and the complete convergence chassis? I can imagine your frustration when you fire-up your beautiful 55 for some TV-wise visitor and it comes up greatly miss-converged. I have the same problem but I never have demonstrated my 55 to any knowledgeable visitor, so waiting 30 to 60 minutes warm-up before taking critical screen shots is no big deal. I've asked this forum's members that have early RCA tube CTVs if they had similar problems and received zero replies. Must be you and I have a unique problem or others are unaware they have a problem or have little interest in the subject?

I checked my power transformer and horizontal output transformer tempts after over 3 hours operation on 113vac mains input on a hot day. The B++ was 410v, Boost was 900v and ultor was 30kv. The horz output tube input control was set for minimum drive and the horz B++ current was 320ma, horz output transformer was 113deg and the power transformer was 140deg.

I will continue freezing all critical resistors and caps looking for sensitivities as soon as my five cans of quick freeze arrives next week. Of course I will report any interesting results.....Tom

---

As I am sure everyone is aware, the CTC2B chassis is an outgrowth of the CTC2; the two chassis have far more similarities than differences.

When I need to view my CT-100 (CTC2 chassis) critically, I never do so without a bare minimum of 30 minutes warm-up, with one hour typical. In particular, fine color balance is not achieved without the warm-up time. I often wonder if a 'time-warp-acquired' set of just-manufactured tubes from RCA Harrison would shorten the warm-up requirement. My sense is that the 55-year-old 6AN8's and 12BH7's require more time to stabilize than when they were new, even though the time on them is not great.

Pete

Hi Tom,

Thanks for the info on the HO trans temp and B+ current. Yours seems to be running nice and cool. That gives me a good benchmark to shoot for. I just got back from a vacation and my freez spray has arrived, so I will try and find some time to look for temp drifting resistors this week to see if I can nail down the large shift in convergence at startup. The funny thing is that after half an hour of running, when the convergence has stabilized, I can turn the set off for 15 seconds or so and the convergence drift will re-occur. But it will re-stabilize in about 2 minutes.

John Folsom has told me that I should replace the flat green power resistors. John says that these type power resistors are known for being a problem. That is the next thing I will try.

Thanks again for the data on temp and voltage/current readings. I will post again as progress is being made.

Bob G.

The original flat green power resistors are rumored to be a little intermittent, causing things to flash and change suddenly. They do not, however, drift wit temperature.

Had to replace those green power resistors on our example before it worked well consistently. A known intermittent part. Beautiful set and landmark engineering for the era. Superb picture with that vintage RCA accurate lollipop color. One of the best pictures I ever saw on a color TV set after the pain of getting it right.

Low level "glow" at CRT cutoff
 

I have this continuing problem with my 21CT55 after a year of operation.With ext video input from the DVE test DVD at blacker-then-black video level input and the contrast and brightness controls fully CCW, I observe a uniform, non-raster, very low-level white glow over the entire screen. This is only obvious in a totally dark lab on the RCA but not on the Sony monitors operating on the same video.

During critical PQ evaluation comparisons with the Sony with no room lights, this glow detracts from the absolute black of the RCA on demo DVE's video relative to the Sony. This is disturbing to me since I never watch LCD TV and suspect my RCA crt's black presentation is similar...yuk!

What to do?? I've tried a few diagnostics:

(1) I determined the 21FBP22A is driven well into cutoff by at least 120vdc.
Besides, the glow is not scan-line defined as if it was going thru gun optics.

(2) By under-scanning the crt with misadjusting the vertical linearity control,
the glow is confined crudely to the raster area of the crt but totally out of
focus. So its effected by the deflection yoke but not the gun optics?

(3) Could this be caused by secundary emmission from the gun elements?

(4) Could it be caused by X-RAY excitation of the gun elements? I am running an ultor of 30kv. The 21FBP22 is rated for 27.5kv so I reduced it to a min of 22.5kv with absolutely no change in the glow intensity.

(5) How about a small air leak? No violet glow in the gun assembly.

(6) I pulled off the crt socket and turned the power on and let the ultor come up. No screen glow so I pressed the crt socket back on. No immediate glow as the crt heaters came up to temp, still no glow. After about 3min running, a glow was barely noticeable. It got progressively brighter until after about 10 min it was at maximum. I directed a fan at the crt neck attempting to cool it but it made no difference.

Question: Is this low level glow I have on my 21FBP22A a common phenomenon observed on many early roundys but only noticed on very dark scenes in totally dark rooms? Since I have only one operational roundy and have not observed another roundy in 30yrs I have no way of finding out. I would be very grateful for any worthwhile replys regarding the cause of this glow and the prevalence of this abnormality in other forum member's roundys.
......Tom

I have seen the glow on modern set's and it was the screen voltage set to high, But I would think you would see retrace. Try turning down the screen controls and see if your problem goes away. I have never seen this on my round color sets and I use them almost every day.
Ed

It shows a warm-up effect, so it is not field emission, which would come on immediately. It's not secondary emission or x rays either, because the normal beam current is off. My only guess is that it could be thermal emission from G1 after it gets heated up. I second Ed's note to see if changing G2 voltage affects it. I have no idea if this was common.

---

A web search shows there were a number of papers written on techniques of constructing grids to suppress unwanted emission,which could come from evaporation of cathode material onto the grid.

Cut-off glow sourse solved?
 

I contacted a crt rebuilder that was mentioned on the ETF site called Magnaview. Talked to Earl who has been rebuilding roundys for 25 years. When I briefly described my cutoff glow phanomination he immediately identified it as cathode contamination of the grid which produces unfocused electron emission when the grid gets heated by the cathode. This substantiates the speculation of John F, Wayne B and Andy. Earl stated emphatically that most all roundys have this glow after 10 years of operation. Its something we all have to live with as we and our roundys get older, something like arthritis.

I requested the forum members to test their roundys with a very simple procedure (even a caveman could do it). Activate TV with brightness, contrast and chroma at full ccw and view in a total blackout room for greater than 15 minutes. Got one reply that no glow was observed after 20 minutes. His crt was a very recent regunned 21FBP22 with no chance of any cathode buildup on its new grid. No one else reported observing the low level cut-off glow or if they did, would rather not comment??

I talked to Scotty about getting mine rebuilt with new original guns. He says no problem, $400 with my dud. He claims he has never observed my "glow" or even heard of the problem, but then he only scrutinizes his newly reguned rebuilts and I doubt in a total blackout room.

My 21FBP22 has not been rebuilt or had a brightener on it. It has good emission on all guns as long as the heaters run above 6.5vrms but falls off rapidly as I drop below 6.3vrms so the cathodes are pretty well depleted, near end-of life. I am now running a switched brightener which supplies 6vrms normal or 7.5vrms boosted at the crt. each gun's emission is way good and well balanced., no change in the glow intensity though.

Really the only time I notice the glow is at the start of the Digital Video Essentials test DVD during the "sunrise out of total night darkness" scene at the start of the video demo. This is a great DVD for setting up, evaluating and comparing the PQ of the early 50s 21CT55 with the 80s and 90s Sony monitors with comb filters. When they all look virtually the same, you know the roundy's PQ is truly optimized.....Tom

I just sent our second 21CT55 to Russia for a TV documentary. It has a chassis that had been working well. The day the shippers arrived, the set developed two independent problems - both due to flat power resistors that had opened up. I would recommend changing them all.

Those flat power resistors are know to cause trouble in 21CT55s and CT100s.

Follow up report:

tested my RCA Cheltenham CTC-4, which has what I think is an original CRT in it. The CRT has the rCA logo on the base, and is engraved "21AXP22A/21AXP22". The painted on date code is unreadable.

With the brightness an contrast controls turned down, and the 3 G1 grids biased to ground potential, there is absolutely NO glow in a ptich black room, after 45 minutes of operation at 25KV ultor voltage.

This seems to confirm the data from Tom and Wayne that says Tom's glow is due to cathode contamination of the G1 grid. Tom, you need to find a good 21AXP22 for your 21CT55 chassis so it can be returned to it "proper" configuration! :yes:

If it were me I would try to locate a really dead dud to send for rebuilding. Seems ashame to rebuild one that is still in pretty good shape. Just my opinion.

I know I have seen such a glow on some sets, though off hand I can't say just which ones. Mostly noticed when doing the setup procedure and all guns are biased off-yet I still have a faint glow on the screen.

Results of glow survey
 

As it stands now, Bob G and Wayne B tests "noglow" but have recent reguned 21AXP22s, no chance of grid contamination from cathode deposits. John F's tests noglow from his original 21AXP22 in his CTC4! This crt is at least 10 years older than my 21FBP22A and should be more contaminated than mine, right. Pete D will test his 15GP22 just as soon as he gets it running again. I need more glow testing of non-reguned roundys like mine.

So out of four roundys tested, my 21FBP22A is the only "glower". Has it been this way when I got it 40 years ago but I never noticed or have I abused it by running over 32kv ultor the last couple of years? Anyway, the glow is only noticeable during very dark scenes when viewed in a totally dark room. I can live with this considering the only fix is to find a known good 21FB cheap (ha) or let Scotty rebuild one for $400 plus a couple hundred two-way risky shipping.

Rebuilding a 21AXP22 if I could find a core is out of the question. There would be the additional core charge and I would have to find an ultor hv boot or hobble up something and I'd be back to 1964 when I converted over to the brighter 21FBP22 in the first place. My 21CT55 is not a restoration, picture quality is the objective here, not proper configuration.

If I get desperate, I can always install my spare 21FBP22 green screen sulfide and hope its been spared the glow of the present gray screen 21FBP22A rare-earth..........Tom