I have a set that has a metal picture tube (16GP4) that is about gone.I have found a (16WP4A) that looks like it may work.Any help on this swap will be
alot of help to me.Thanks.

The problem you are going to run into is in two places. 1. mounting, 2. HV supply.

The 16WP4a is an all glass tube, and cannot be used in the original mounting configuration. Depending on how the tube is held in (is it chassis mounted or cabinet mounted?) you can make a strap and hardware that will hold the tube in place, but its not easy, and pressure points on the tube will cause it to tail and send glass flying into you!

The other concern is the HV lead. You will need to steal one out of a newer set or a computer monitor to replace the one that clips onto the metal shell. This in itself is not difficult unless the HV rectifier socket is hard to get to.

is there any way you can get a shot of how the 16GP4 is mounted?

Thanks for the fast reply.The tube is chassis mounted with a strap around the
picture tube.It is an HALLICRAFTER MODEL 818.The anode will not be any
problem to replace.I think the 16WP4A takes a double ion trap and the 16GP4
uses a single?Got a super deal on this 16WP4A if i can get it to work.I might
have some trouble finding the double ion trap, but i think you may have saved my set.

yes the GP4 uses only the single field ion trap, so you'll need to find a dual field. I would also consider buying some thin foam tape to put along the inside of the strap so it will not bite into the tube when you strap it in. i would also hold the tube in place on the chassis to make sure the CRT will clear chassis parts. You wouldn't want it to hit anything like a filter or tube.

good luck!

Looks like i found a good site.You sure helped alot!I have been reading the forums here and looks like alot of knowledge can be had by only asking.Again many thanks for all your help.

I would think that there may be a little more to this than shoving another crt in the space the old one came from. Besides physical charictaristics I would think that there would be some electrical differences. I know focusing methods can vary and cause swap trouble.

Are all of the old electron guns the same except for ion trap type? I know most of the filament voltages are the same but are the pin configuration and electrical charictaristics the same?

At least some things to consider.....

The tubes have very similar characteristics. Same focusing method. The only differences are physical characteristics (all wp4 is all glass, and 18-1/2" long instead of metal shell and 17-11/16" long), and higher anode voltage (16k vs 14k for the GP4), and of course the dual field ion trap (instead of the single bent-gun type for the GP4) If he can physically fit it in his application, he has nothing to worry about. Grid voltages and the like are identical.

I may have some hv problems now (14k=GP4).I checked the hv with my probe
and max is 11k.Sams (set-124,folder-6)says about 13k on it.Well the 2k
difference may be hurting me some but the screen is so dim you have to turn out the light to see it.Adjusted the trap and it did help but not very much.So
what do you suggest i do ? Maybe a leaky cap? Where? This set has been a bear to get this far with it.I have replaced all output tubes and the hv rect with new ones.Forgot to tell you i replaced some capacitors but mostly in the vert. and horiz.circuits.A couple resistors that was way off value.To top it off the tuner is being rebuilt at Quality Tuner (nice guy).Tried a Beltron Restorer
on it and no go.So i don't know if the tube has been restored before or not.A
brightener sure helps alot so i came to the conclusion that i had a bad tube.
Open for any suggestions on how to proceed with this.I was about to give up
until i found this site and all the great help.So, with the help here, the OLD SETS have a good chance of living again.They are a very important part
of our past.Thanks Again-Don.

hey Don,

Have you put the tube on a tester yet to see what its emission is?

as far as high voltage goes you should be just fine with 13k B&w does not need to have exact high voltage to maintain luminance. 11k you should still see a good pic. Does it bloom when you crank the brightness? if so, then it is an HV problem, if not then it is a CRT problem

Look at your service data and see what the voltages are supposed to be at the CRT socket. if any are off by more than 10-15% good chances are you have some chassis work to do.

Or it may be a problem in the circuits driving the grid and cathode. The grid voltage should be only slightly negative relative to the cathode with the brighness control all the way up.

I checked the tube and it goes about 3/4 the way over but it drops fast on the life test.The brightness contol works great with good control.There is no
blooming of the screen at all.I'll check my voltages to the tube to make sure
they are right.Looks like some of them has to be on the money.I'll let you know if they are off, because if they are, i'm lost.I should get my tuner back
by next week and i bet i have more problems to deal with.So hang in there
with me on this i'm sure going to need your help.I already see some vert fold
over at the bottom at the screen now.Thanks Again,Don

You can try re-activating the tube. This is different than rejuvenation.

Just bump the filament voltage up to about 8 volts, and let it sit for an hour or two. Then put it back down to 6.3 See if you woke up the cathode at all. If your tester does not have filament voltage selection, just put a brightner inline with the tester.

Can I "re-activate" my crt that already uses a brightner? Obviously I would have to try a higher voltage than mentioned in this thread but what would be safe? I wonder how much voltage the filament can take before POP....

If you're tube already has a brightner on it, there is not much more you can do other than to try rejuvenation. Usually a weak CRT will benefit from adding a brightner after rejuvenation.

CRT filaments are about 100% over-rated so they can safely run at 12v. however this does shrten their life, and if you go beyond 12, they open in a rapid fashion.

Okay i tried the brightner on the tube for about 2 hours.Took it off and fired
up the set and it looked good.Turned power off for awhile, and tube is about
the same as it was.Looks like the brightner has to stay to be watchable.I don't want to watch it all the time just short term plays at the time.So how
long do you think its got with the brightner? Nice set and its a keeper.Thanks!

try rejuvenation. Most CRT testers have this function and instructions on how to use it. After rejuvenation keep the brightener on it. Just use it till it dies. Not much more you can do after that

...

My 1956 Philco has had a brightner for over 20 years. I have posted on this set before so I will try to be brief. I bought the set in 1982 or 3 at the Goodwill, which by the way at that time was a modern day collectors dream. Back then there was stacks of 50's Black and white sets and many color roundies all the time. Many of these sets were commonly used up to that time and were just getting discardable. My Dad worked at a Sears Roebuck catalog store then and it was right next to the ONLY Goodwill I had ever seen. Now they are everywhere. Anyhow my Dad's job allowed me to keep an eye on the cool junk store.

Anyway my Philco cost $10 and gives good service TO THIS DAY with no recap. Only an occasional tube and once back in the 80's we sent it to the shop for a resistor that had caused the sound to become problematic. I guess my being young at the time gave me a premature eye for the nostalgia and pure beauty of the old sets.

As far as my Philco's use goes I used it daily from when I purchased it until 1986. Then I went in the Army until almost 1990 so the set was dormant. When I got out I used it only part time and had upgraded to a Zenith color roundie with remote control. Still good stuff, even then. Even then I was amazed with the reliability of the Philco and had grown attached to it. The 50's sets were getting rarrer by the early 90's. Then there was no internet in everyones home (or room) like now and I feel like its popularity opened new doors to finding old sets. For the most part we don't think of 50's sets as being "rare" now because there are a lot of them out there and we now have an instant way to locate nearly anything we want.

Back to the point after leaving the folks house the Philco remained dormant again until around 1994 or 5 after I had bough my own home. All the rest of the time I have played the set for an hour or so 3 or 4 times a year. At this point its like I am playing some kind of game trying to see how long a television can last without restoration. If Philco were still a company they would probably want to purchase it back to put in their archives, or a museum.

So, a brightner is NOT a death sentence. I think people get the wrong idea when it comes to brightner's. What it really means when you find a set with a brightner is that the set has a lot of hours of use and the crt has weakened with age and has lower emission. It would be somthing to consider in purchasing a set because you will eventually need a replacement tube but again not a death sentence.

My old set finally has gotten so it takes a good 5 minutes to become viewable in a lit room. Also the picture gets silvery looking when you play with the brightness control. Still in all the set still does its job. Funny the more I use the old thing the better the picture seems to get. It may outlive me and is almost 15 years older than I am......

I sure appreciate all the great info i'm getting here for sure! Now back to the tv . I have a Beltron picture tube restorer model 8080A and have tried to clean and restore it.The Beltron works okay so thats not a problem.What it does when i try to restore it is NOTHING.It doesn't clean or restore.I upped the filament voltage some, tapped on the neck (lightly) and still no response from the tube. Makes me think somebody may have already did that before i bought the set.I didn't leave the set on long after the cool down because of the tuner deal.It may come up good ater a 10 minute warm up or so.Plus i can always use the brightner on it.Looks like someone has a good run with one.Still waiting on that darn tuner so i can get this tv playing.I might add with all the great help i'm getting here.Will post a picture of it, when its done, and let you know what a great job you did helping me repair it.

RCA 6-T-72 chassis KCS40B serial number A1957811 16" CRT 16GP4. Looking to get it to work. I am in Southern California. Any suggestions? Thank you


Is there a CRT that will work on my set. I believe its a 16GP4.Any suggestions?

Not easy to put another crt in , the tv is made to fit 16gp4

If your 16G is down to air and you're within driving distance of Milwaukee I have a spare 16GP4 that works on a brightener that I'd let go cheap to anyone willing to pick it up in person.

Just how well/long do the brighteners work/last?
As mentioned, my 24AHP4 is a bit weak, slow to come up to brightness, but after a few min, gives a pretty good picture, obviously on it's last legs, who knows how long.

https://frank.pocnet.net/sheets/049/2/24AHP4.pdf

The data page clearly states that the heater can run off of AC or DC current, so I was thinking of getting a 7 volt 2 amp dc regulated power supply, and giving the CRT tiny boost, 0.7 volts is not very much, but it will help a tiny bit, and that's all I really need. Right?

How long a CRT will last on a brightener and how much of a voltage bump your tube will need are variables.

I've ran CRTs for months on brighteners and seen no drop off in performance before finding better CRTs. I've also seen CRTs without brighteners wake up on a tester then die in a few months of regular service (the Sylvania 21FBP22 in my Zenith 29JC20 for instance).
If a CRT can produce an acceptably bright picture in the lowest room lighting your comfortable with without a brightener, then there's no need for one. A period brightener will spit out around 8.4V if your CRT doesn't need that much to hit acceptable brightness you can try less and see if it lasts longer...In your set since there's no cabinet I'd run probably run to fail then chuck the chassis on the parts donor shelf.
There's tons of parts chassis out there*, and there's tons of complete sets out there.
*I just liquidated 2 rectangular color parts chassis (the stripped parts take up less space off the rusty chassis) and I have 2 more I'm probably going to do the same to soon.

How long a CRT will last on a brightener and how much of a voltage bump your tube will need are variables.

I've ran CRTs for months on brighteners and seen no drop off in performance before finding better CRTs. I've also seen CRTs without brighteners wake up on a tester then die in a few months of regular service (the Sylvania 21FBP22 in my Zenith 29JC20 for instance).
If a CRT can produce an acceptably bright picture in the lowest room lighting your comfortable with without a brightener, then there's no need for one. A period brightener will spit out around 8.4V if your CRT doesn't need that much to hit acceptable brightness you can try less and see if it lasts longer...In your set since there's no cabinet I'd run probably run to fail then chuck the chassis on the parts donor shelf.
There's tons of parts chassis out there*, and there's tons of complete sets out there.
*I just liquidated 2 rectangular color parts chassis (the stripped parts take up less space off the rusty chassis) and I have 2 more I'm probably going to do the same to soon.
Many years ago, I've seen people running two briteners on a really tired CRT.
They didn't worry about hurting it. The tube is junk anyway.

You can use a transformer or a brightener with a resistor run it at 7 volts or so and you will be happy and ßo will the crt, I've done it

Just how well/long do the brighteners work/last?
As mentioned, my 24AHP4 is a bit weak, slow to come up to brightness, but after a few min, gives a pretty good picture, obviously on it's last legs, who knows how long.

https://frank.pocnet.net/sheets/049/2/24AHP4.pdf

The data page clearly states that the heater can run off of AC or DC current, so I was thinking of getting a 7 volt 2 amp dc regulated power supply, and giving the CRT tiny boost, 0.7 volts is not very much, but it will help a tiny bit, and that's all I really need. Right?

D

What set uses this tube is tube round I guess?

A true hack would be to use a smaller crt with magnifier lens to make screen look larger AS OEM.


Smaller crt would be lighter for mounting less ideal tho.

I have a spare Zenith chassis with a 16G in it I will check it this week for you.