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Old 06-20-2016, 09:40 PM
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N2IXK N2IXK is offline
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Wtb: Nos 25vabp22/25vadp22

Looking for a NOS tube to replace the cataracted one in the Heathkit GR-900 I just finished building. Would prefer one close enough (NY/NJ/CT) for pickup to save shipping if possible. Anybody have one of these kicking around?
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Old 06-21-2016, 01:41 PM
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miniman82 miniman82 is offline
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Does your tube test bad or something? Most bonded tubes end up having some cataract even if it's just around the edges, so if yours is still good I would do the surgery and put it back in.
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Old 06-21-2016, 03:44 PM
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N2IXK N2IXK is offline
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Tests as new. I have concerns about the safety of the usual "cataract removal" procedure, particularly on a set that I may put on public display at some point.

The bonding resin is the heart of the implosion protection system on these tubes. The resin holds the whole front of the tube together in the event of impact, just as a car windshield retains integrity in a crash. If you remove the bonding resin, and just stick the faceplate back on with tape/RTV around the edges, the protection provided by the laminated faceplate is gone.

I have a line on a 25VCZP22, which might fit and avoids the entire cataract issue by being a tension band type tube.
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Old 06-21-2016, 07:33 PM
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Electronic M Electronic M is offline
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Quote:
Originally Posted by N2IXK View Post
Tests as new. I have concerns about the safety of the usual "cataract removal" procedure, particularly on a set that I may put on public display at some point.

The bonding resin is the heart of the implosion protection system on these tubes. The resin holds the whole front of the tube together in the event of impact, just as a car windshield retains integrity in a crash. If you remove the bonding resin, and just stick the faceplate back on with tape/RTV around the edges, the protection provided by the laminated faceplate is gone.

I have a line on a 25VCZP22, which might fit and avoids the entire cataract issue by being a tension band type tube.
I beg to differ. The glue is not the end all be all of implosion protection. In the mid 60's sets came with either the glued on safety glass (21FJP22) or the a separate safety glass (21FBP22) with a rubber outer ring to act as a spacer (and to seal out dust) that was held against the CRT face by the set's CRT mounting. Both designs were sufficiently safe and co-existed on the market a while before cost and simplicity of the glue type won out.

Unless you PLAN to attack the CRT face with a bat or some such there is little difference.

I have 6 sets with non-bonded safety glass or CRT's that I've done the cataract removal on in my bedroom that I'm within 5-10' of 8-20 hours a day every day and I'm literally more worried about the house collapsing (probably won't happen in my lifetime) than I am about CRT implosions......Now if the national sledge hammer jugglers' association pays me a visit that may change.

If you have it on public display keep it behind glass...If you don't the knobs WILL go "missing" and it's condition will deteriorate.
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Old 06-21-2016, 07:53 PM
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miniman82 miniman82 is offline
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No disrespect, but I doubt anyone is going to come off a tube because yours has a cataract. We've all had tubes with them, and done the required procedure to get rid of it. Never know though, if that one isn't rare and someone has a good one...

Like I said though, your problem is going to be finding another that also doesn't have the same issue.
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