Successful Tube Swap - You Can Do It Too!

bungy

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I have a spare 4900 with an unacceptable amount of burn and I wanted to extend its life in case I need it. I had been studying raster tube swaps and other posts of the monitor gurus for a few months now and felt pretty confident I could handle it.

Near where I work, there is a dropoff container (truck size) for recycling bulky electronics. I always check it out for junk computers, but I have been bringing 19" TVs home in preparation. The first one I got was a Sylvania with the correct deflection angle, but the wrong neck pinout ("I told you we should have got a Zenith!"). Next up was a Zenith with the correct deflection angle and pinout - the model number was Z19A02G. The connectors for the yoke & degauss coil on the donor were the same, so I brought them with the tube and installed it.

Connected it up to a Tron and the picture came up, but it was inverted and squished and blurry. I knew enough to swap some yoke wires to fix the inversion, but I could not expand the picture enough to fill the screen. Some more research and I decided to swap the yoke & purity rings. This was the part that scared me the most, but it was easy as pie. While I was at it, I moved the original degauss coil back.

Turned it on, and the picture was beautiful. Still needs to be manually degaussed / adjusted, but that's easy, too. I've read a lot that says to keep the yoke with it's tube and I don't know if I was just lucky, but they seem pretty easy to swap.

I think I'm going to put this in my Satan's Hollow as Satan has some bad burn (Ha!) and swap another tube into that one.

If you have a monitor with bad burn, I say go for it! 19" TVs are practically free these days and there is more than enough info here to help you along.
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Nice! so far it seems the zeniths are the most popular for tube swapping. Whats the tube# on the back of the new tube? a48...

i did the same thing as you, cruise the forums looking for info and listening to people like modessit makes it pretty easy.
 
The tube number on the new tube is A48ACB32X.

I got it installed in my Satan's Hollow and I was able to fix the color issues by adjusting the yoke. But it looks like there is some ghosting going on. What adjustment do I have to make to fix that?
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I'm gonna say purity rings.

In general you want to keep the rings that were on the tube (marked and reinstalled to the same location as a good start) and swap just the yoke (IE: The yoke follows the chassis)
 
Gah. The old yoke had the purity rings permanently connected to it. I'll mess with it tomorrow and see what happens.
 
I have used the original yoke on my tube swaps and your supposed to keep the purity ring assembly with the donor so you dont have to mess with it but since yours is attached you will have to use the old one or buy a new one and adjust it in.
 
Nice job! One of these weekends I've got a big batch of tube swapping to do. I've got about a dozen tubes out in the shed, it should be fun. Anything that won' t play nice I'll just order a universal for.
 
I got the ghosting almost completely gone. I tried cutting the ring assembly off the donor yoke, but when I put it on, it didn't look right at all - must have gotten messed up. So I went back to the original rings and tried to do it by the book, but that looked even worse. So I just tweaked & tweaked until I figured out how it worked and adjusted it almost completely away.

I am thoroughly impressed with the results and I'm going to continue swapping out the tubes on all my raster monitors.

Incidentally, I got the MCR power board working in Satan's Hollow so now I don't have to keep swapping between it and Tron.
 
To get the adjustments as good as possible - you need to use a game or board that can product a grid test pattern, then you use that to line all the colors up as close as possible.

I did a tube swap on a 13" K7000, new yoke was a perfect match to the old one so I just dropped the tube in and swapped yoke plugs. Worked great save for a teeny itty bit of convergence issue, but honestly the picture looked so nice it wasn't even work dealing with.

Added your tv to my list! Thanks!
 
If you have adjusted the purity rings to the best ossible pic and there is still an alignment issue (the ghosting you are seeing) you can install magnets to help as well. You will sometimes see these thin strips of paper sticking out from under the yoke on some machines. These are magnets used for the finishing touches on purity adjustments. I haven't yet found a good source for the magnets but I am looking and chasing a few leads...
 
Here is what it looked like after I got the purity rings adjusted - of which I only adjusted the middle set. Not quite perfect, but definitely good enough.
 
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The last time I needed magnets for a tube, I just went to Home Depot and grabbed a bag of those magnetic heat vent covers... it's a few bucks for 3 huge magnet sheets... but you could also use a fridge magnet.

DogP
 
The last time I needed magnets for a tube, I just went to Home Depot and grabbed a bag of those magnetic heat vent covers... it's a few bucks for 3 huge magnet sheets... but you could also use a fridge magnet.

DogP


I agree, but the magnets used are very weak. I have found that the really cheap magnets used for business cards, the kind that fall off of the door when you shut it, work the best. I have never had much luck with good quality magnets, they overcompensate. I'll check out the vent covers you mentioned...
 
I bought a bunch of the strip magnets from hawkeye picture tube, they are like 1/2"' wide, 3" long, something like that. They have glue on one end.
 
I agree, but the magnets used are very weak. I have found that the really cheap magnets used for business cards, the kind that fall off of the door when you shut it, work the best. I have never had much luck with good quality magnets, they overcompensate. I'll check out the vent covers you mentioned...

Yep... that pretty much describes the vent covers. If you try to cover the vent with the vent open, when the heat turns on, the covers blow off :p .

DogP
 
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