Rejuvenating the Emperor (CRT) - Videokarma.org TV - Video

Carmine · #1 01-03-2010, 09:07 AM

Spent some time this morning, hoping to revive the blue gun in the Emperor enough to watch Coronation Street in full color, rather than shades of red and yellow...

As expected, the blue gun tested dead while the others were "ok". So I moved on to the rejuvenate setting (I borrowed Dwight's Heathkit CRT tester/rejuv.).

The instructions have you increase heater voltage until you read 8.5 on the gun scale, then dial heaters back to 6.3v, crank voltage until you see 8.5 on the gun scale again... (repeat three times). If at anytime the "restore" light flashes (rather than slowly increasing in brightness), you must stop immediately.

Well long before I noticed the restore light, I saw the minor fireworks in the tube around 8v on the heater. I repeated a few times with similar results (the restore light did in fact flash).

The problem is, the "gun scale" doesn't even move off the peg, let alone get anywhere near 8.5. The internal fireworks begin long before I see anything on the gun scale. What to do?

Also noticed that the green gun lights much brighter than the other two, as seen here... This is more noticeable on the CRT tester with heaters running at 8v, but occurs when connected to the set too.

After I reconnected the tube, I did notice the green was so much stronger that I had to dial back the drive. Blue is still MIA... Well, not totally dead, but very weak.

andy · #2 01-03-2010, 09:52 AM

000

Carmine · #3 01-03-2010, 09:55 AM

Heathkit IT-5230

Blue does show up on the screen in the service position, but will not balance with the others.

sampson159 · #4 01-03-2010, 05:28 PM

sounds like it is time to replace it.what crt do you need?i have scrapped a few things and may have it.

Carmine · #5 01-03-2010, 06:54 PM

Quote:

Originally Posted by sampson159

sounds like it is time to replace it.what crt do you need?i have scrapped a few things and may have it.

Thanks.. I actually have a couple spares myself, black matrix CRTs in fact.

But it's like this... It will be years until I can perform a proper restoration on this TV. There are a lot of hack repairs, but it does work reasonably well now with the exception of the weak blue gun (and some other minor issues).

I'm giving this set a place in my living room, so I'd at least like to be able to turn it on now and then and have it produce a reasonable picture. I'd rather hold off on the CRT change if at all possible, and just do that at the same time as a full recap. Most of the time, it will sleep behind doors.

Right now, a little jolt is all I have time for. This seems like a perfect rejuv scenario.

eberts · #6 01-07-2010, 06:55 AM

The reason one heater is brighter is you have a parallel wired heater in the electron gun on tube in your photo. Obviously it is defective. That type of gun was used in first rectangular tubes during the mid 60's. Later most manufacturers when to a lower current series wired string heater, except for Admiral when they manufactured their own tubes. Your tube needs to be replaced or reprocessed.

Carmine · #7 01-24-2010, 10:50 AM

Well I thought I'd update this thread to reflect some news... I have the blues.

...and I couldn't be happier.

Compare that to the "before" (Believe it or not, that picture is supposed to be CoLoR)

Now Mr. Spock's uniform isn't violating regulation.

Captain Moody advised me to put the CRT tester/rejuv into the test position and keep upping the heater voltage until I saw some life on the blue gun. I did as told, and suddenly, around 8v, the blue gun jumped up and pegged the scale!

So I know have a set that functions on all three colors, without a ton of work. After re-running all the tests, the tube now shows very strong, and the pictures back that up!

drh4683 · #8 01-24-2010, 10:54 AM

Very nice! How is everything else with the set?

Carmine · #9 01-24-2010, 11:05 AM

Quote:

Originally Posted by drh4683

Very nice! How is everything else with the set?

Well Doug I think you'll be pleased with the progress on the rest of the set. I'm in a remote location right now (as in rural Ohio, not Space Commmandville) and can't upload any new pictures. When I do, I'll put them in a new thread, as befits the Emperor.

*zenithfan1* · #10 01-24-2010, 02:34 PM

Cool! That will save a lot of work, that 8v method is really great. I've revived a few I thought would never come back. I wrecked one too but you can't always win.