When the Turks first shot their guns they broke their noses. When E M decats....

[Electronic M]

Well today I tried to remove a cateract on an RCA tube. Here is the gruesome story in photos and words.

I started by gouging out some of the PVA so I could pry the glass up, but because I could not locate any usable wood at first I tried prying with a screw driver and ruined the safety glass. This was yesterday. I made some progress, but the sun went down and I decided to put it in a tray of water over night.


The next day I made good progress, but between the chip from yesterday and the uneven pesssure of the small shims cracks started to develop.


Eventually it got to the point that I could only chip the lense off with a screwdriver...


But even with the googles I was wearing the glass chips were too unpleasent to tolerate. The next thing I did was VERY STUPID (understand that my brain does not work much if at all in 97 degree heat). I took the sizzleing hot tube and put it back in the cool water! As I walked away I heard a ping and hissing/gurgleing sound, this is the result.



The bell and face cracked and I could not be sadder and madder at my self than I was was when I snapped that series photos, despite the small reilef that I was not injured in what could have been a violent implosion.
I think I learned a valueable lesson about thermodynamics from this tragety if nothing else.

The less disasterous less sucessful Zenith process is to come in my next post.

Tom C.

PS: what should I do with the RCA tube now?

[Electronic M]

And now the Zenith decat process.

I left the tube in the sun untill it was very hot and then tried to pull wire through the glue the wire went about 1 or 2 inches in before snapping.

I tried various thicknesses of wire both hot and cold as well as the one i setteled on. Which cold was able to go in about the farest distance before snapping.

I initally heated all the wires with a fillament transformer that, as the thickness of the wire went up, prooved to be too weak. I then managed to find the transformer that I wanted to use from the beginning. It is a transformer from a computer battery backup power strip, and this thing has got some cahonies (the low voltage secondary is wound with wire so thick that it is tough to bend).






This worked well, but the sun was going down (to the point where the work space was in shade) and the tube started to cool. I also had a hard time finding a place where the wire would melt the glue well. The wire was hot to the point that the glue would smoke when I would turn the voltage up, but the wire would stick to the glue and refuse to go in further than 2".


The following are my most important questions to those with Zenith cateract removal experience.
Is the glue on Zenith round tubes somehow harder to work with than the rectangulars?
And when one cuts a zenith cateract with a hot wire, is it suposed to be like a hot knife through butter? If not at what rate does the wire normally slice the glue? And how hard does one need to pull the wire?
How hot should the wire be?

Sorry for all the questions. I've never done a cateract before and I'm not sure what I'm doing wrong. I like restoring and collecting color TVs enough that I realize I have to learn how to do this or live with cateracts (which I'm sick of).

Tom C.

[Eric H]

You need to use a Steel wire, like a Guitar string. Copper isn't strong enough.

[damen]

I used Ernie Ball custom gauge 18p guitar string and hooked my batterie charger to a rheostat I think I put it on 6 volts and raised the power on the rheostat till the wire got hot and pulled it back and forth between the lens and tube and went all the way threw in less than 5 minutes I did heat the front a bit but it was not real hot.

[Electronic M]

Steel wire! (slaps forhead) I thought about getting steel wire when I bought the copper wire. I guess I should have acted on that thought.

Thanks.

Tom C.

[DaveWM]

you dont need to heat the wire, just pull it thru. The zenith that I did had adhesive that was more like thick gel.

Yea, not a good I idea to put a hot CRT in cold water, be glad you did not get hurt.

the key to the RCA is to soften the pva with an extended soak in water (weeks if not months), then you can pull about 1-2" of the pva out around the perimeter. then you put it out int the sun face up, small wood wedges (I used chop sticks) get LIGHTLY tapped in just till they are snug, then walk away for 15min, come back and tap them in some more (they should be loose) walk away again. keep doing this, if you look closely you should be seeing fissures forming in the PVA (the sun will cast a shadow thru the pva, help to make them show up. How quickly this will go depends on the heat of the sun, but as you learned the hard way, it takes pressure heat and time.

I used saftey wire for the zenith, pretty sure its stainless steel.

[ctc17]

First thing...get that thing on the grass!

Use guitar string and screw it to two wood blocks. Let the face warm up and saw it back and forth and it will go right through. The hard part is cleaning that stinky green goo off both sides.

What was the rectangular crt? 25xx22?

[leadlike]

I'm impressed that what little was left of the safety glass was enough to keep the crt from turning into a messy implosion. Just be glad you didn't get nailed in something like that.

[Kamakiri]

I did my de-cataracting with a heat gun set on low and waved gently over the screen, starting in a corner and working my way inwards. Took me about 15-20 mins, and the glass popped free. Nobody likes that procedure, but it worked for me

[DaveWM]

I don't think its a question of not liking using the heat gun, more an issue of uneven heating and possilbe implosion (using low and your technique prob has a lot to do with how safe it is). the deal with the sun heating is its gradual so we presumeably less likely to cause thermal stress (no proof yet, clearly not good to take a sun heated CRT and put in cool water).

there has been a couple reports of implosion using the heat gun, but then again it may be something else unrealated, just a theory on the cause of failure.

Perhaps it all comes down to technique used.


The water soak is prob the least stressful as no heat is involved at all. It just take a VERY long time.

when I did the sun thing I let it sit outside as the sun set, the assumption is again a slow cool down. no proof this makes a differenece, but so far so good.

[Electronic M]

The rectangular RCA CRT was a 22JP22 and was a replacement for a different number in a Zenith TV set I bought from miniman (who probably will not be happy after reading that).

I don't have grass that I can safely put the tube on. I live in an apartment building that allows pets, and many dog owners let their dogs run free. This means that I have to be outside to run K-9 interference. The best place to do the catract is just out side my garage where I can be in the shade while waiting for the sun to get the tube hot enough, run K-9 interference, and have electricity for the hot wire in reach.

Though the wire would go in some cold I had to pull very hard and it would seem to get stuck a short way in so I don't want to rule out hot wire untill I have sucess with the cold.

I've been using a 3 to 5 gallon bucket to hold the tube upright if anyone was curious.

I chose the round Zenith tube for my first Zenith cateract because unlike the 22JP22 it was not part of any set I own, but rather a spare I had laying around so if bad things happen I don't NEED to seek out a spare.

Dave, what do you mean by "safety wire"?

I have three other Zenith cateracts in sets that I either watch or am planing to restore so I intend to get this process down to a science.

Tom C.

[Electronic M]

I'm going to get some steal wire and try again today if I can.

Tom C.

[DaveWM]

http://en.wikipedia.org/wiki/Safety_wire

[Kevin Kuehn]

Scary. Glad you didn't get hurt.

My dad and I used to use an old Lionel variable AC train transformer and a nichrome wire on a bow to cut foam wing cores. I wonder if this same setup would work on these crt's. You can even setup a few pullies and a weight to pull the bow at a constant speed. Dave probably knows what I'm talking about.

[DaveWM]

I do indeed, got the same deal with the bows... lots of fun cuting wing cores.

That is why I had the wire in the 1st place (and a variac). fun thing about TV's is they don't auger in...