He just wants to fit this in a place that's too small and refused to accept that the metal band is part of the structural integrity.

By Jove I believe you've got it!!!

Best regards
HP

 

He just wants to fit this in a place that's too small and refused to accept that the metal band is part of the structural integrity.

Hedging you bet there #12???


TTFN
HP

 

Hedging you bet there #12???


TTFN
HP

No simply a bad habit taking charge while I wasn't paying attention.

 

Say what! A politically incorrect #12?! Another illusion shattered

Best regards
HP

 

Say what! A politically incorrect #12?! Another illusion shattered

Best regards
HP

I have plenty of, "politically incorrect"! I merely refrain from demonstrating it on AAC, most of the time. We need a certain level of politeness to be effective here.

I am an iconoclast by nature. I don't respect the clock, the calendar, or self-important prigs. I have worked many times when the job starts at 11 PM or Thanksgiving day, and I fire customers for expecting me to be anything except pragmatic. Some of my best work has been knocking the halos off the heads of physicians.

You, for instance, might be called bombastic or eloquent. I find your prose entertaining, so I don't take gratuitous shots at you.

 

I have plenty of, "politically incorrect"! I merely refrain from demonstrating it on AAC, most of the time. We need a certain level of politeness to be effective here.

I am an iconoclast by nature. I don't respect the clock, the calendar, or self-important prigs. I have worked many times when the job starts at 11 PM or Thanksgiving day, and I fire customers for expecting me to be anything except pragmatic. Some of my best work has been knocking the halos off the heads of physicians.

You, for instance, might be called bombastic or eloquent. I find your prose entertaining, so I don't take gratuitous shots at you.

Right off hand I'd say we're agreed on the politics front! -- I hope the intended satire was manifest in my last post?! -- IOW Your lack of political correctness is as refreshing and pleasant as it is apparent!

Best regards
HP

 

"Thank you...thank you very much." (Elvis Presley)

 

I can't resist quoting this (although I probably should) that Albert Einstein said the definition of insanity is doing something over and over again and expecting a different result.

 

Kind friends:

I seem to have encountered an insurmountable obstacle as regards my attempts to retrofit a vintage TV receiver with a 'modern' CRT...

Despite my best efforts I find that removal of the mounting band from CRTs having a diagonal face dimension greater than Ca. 28" (~71 cm) invariably results in instant breakage of the tube! --- Please understand that I have exercised every precaution by way of avoidance of 'nicking' or otherwise damaging or stressing the glass! -- In point of fact my last attempt consisted of merely 'undoing' the cinch with surgical picks sans contact or increased stress on the envelope -- Nonetheless the tube suffered instant implosion upon release of the band's tension! -- Ludicrous though this may sound - I'm compelled to wonder if the band serves as some manner of structural 'member'?!?!

Having gone through four pristine NOS tubes in this fashion I'm hesitant to jeopardize my two remaining 'prospects' with any further (of my) 'bright' ideas --- Any thoughts, advice or 'magic spells' will be greatly appreciated!!!

Best regards
HP

Warming it up would make the glass less brittle - that's all I can think of.

There was a time the implosion guard was a plastic "cap" for want of a better word, clamped over the faceplate by the steel band round the outside - salvaging the old implosion guard to put on the replacement CRT was a routine part of the job.

Not sure how well I remember - but those guards may have been available as a retro-fit for CRTs originally installed without one.

When I used to harvest stock from the local tip, I wedged a CRT diagonally against the ram in the hydraulic waste compactor. The motors were doing a lot of heaving and grunting, just as some bloke went up the steps to chuck his rubbish in the chute, the CRT imploded - the aluminisation on the back of the phosphors produced a blizzard of silver snow.

One occasion I spotted an unrepairable returned by a competing trader, so I did a bit of footwork to make sure it didn't end up in my lot. As my boot dismantled the wooden cabinet, the faceplate separated from the flare - they're glued together!

 

I can't resist quoting this (although I probably should) that Albert Einstein said the definition of insanity is doing something over and over again and expecting a different result.

Indeed! Or to render another illustrious quote: "Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth" -- Doyle...

Despite copious evidence of the fact, the notion of (what amounts to) a 'two piece tube' seemed inadmissibly bizarre - hence my four approaches to the same problem - with equally lamentable results --- Good deal I posted here or I'd likely have been through all six, or -- much worse -- a tube may have lasted just long enough to 'nuke' the receiver!

Best regards
HP

 

HP: out of curiosity: have you tested the new tube for compatibility with the old electronics? E

 

the faceplate separated from the flare - they're glued together!

Ah! Yes -- Seems the adhesive ages poorly -- leading to what those wiser in the ways of restoration than analogy term 'cataracts' -- I'm told employment of heat guns to delaminate the safety glass from the tube proper passes for valor (and 'hiked' health insurance premiums) among 'resurrectionists' of home entertainment equipment!

Best regards
HP

 

Ah! Yes -- Seems the adhesive ages poorly -- leading to what those wiser in the ways of restoration than analogy term 'cataracts' -- I'm told employment of heat guns to delaminate the safety glass from the tube proper passes for valor (and 'hiked' health insurance premiums) among 'resurrectionists' of home entertainment equipment!

Best regards
HP

The glue seems pretty reliable to me - it was the only one I've ever seen fail that way.

 

HP: out of curiosity: have you tested the new tube for compatibility with the old electronics? E

My approach is modification of the electronics to match the tube (hence my insistence upon a complement of 'neck accessories' applicable to the replacement tube{s}) --- The greatest challenge of which is 'matching' of the dynamic convergence circuitry to the new yoke/tube...

Best regards
HP

 

The glue seems pretty reliable to me - it was the only one I've ever seen fail that way.

Generally failure presents as formation of opacities -- which require removal of the bonded safety glass and all traces of adhesive followed by either re-bonding or 'tacking' the glass into place... Indeed removal of the the safety lense is the most difficult and hazardous part of the job (requiring carefully applied heat -- and a suit of 'armor')...

Best regards
HP

 

Generally failure presents as formation of opacities -- which require removal of the bonded safety glass and all traces of adhesive followed by either re-bonding or 'tacking' the glass into place... Indeed removal of the the safety lense is the most difficult and hazardous part of the job (requiring carefully applied heat -- and a suit of 'armor')...

Best regards
HP

I wasn't talking about that bonding - I was talking about the faceplate is glued to the big funnel shaped bit of glass that the neck sticks out the back of.

 

I wasn't talking about that bonding - I was talking about the faceplate is glued to the big funnel shaped bit of glass that the neck sticks out the back of.

That's a new one on me? You mean a tube so constructed that adhesive functions as the frit seal!?!? --- I'm thinking an alkali silicate or some such...?

Best regards
HP

 

Just guessing... based on Crutschows observation... when the final vacuum is pulled on the CRT, is it done with the whole tube heated at all, to simplify drawing the vacuum... that being the case, the band may be to mitigate stresses induced by the heating...
Though I wouldn't think that the tube would be heated to a point of annealing the glass... that's why I'm still an amateur...

 

Think for a moment. What pre-stress would removing the metal band release?
If the front glass had some convex shape on the outside or a concave shape on the inside, releasing the metal band would allow the front glass to expand laterally as its center is pushed into the vacuum chamber.
The instant the glass is allowed to expand laterally, the strength of the curvature is destroyed, and so goes the entire structure.

 

Think for a moment. What pre-stress would removing the metal band release?
If the front glass had some convex shape on the outside or a concave shape on the inside, releasing the metal band would allow the front glass to expand laterally as its center is pushed into the vacuum chamber.
The instant the glass is allowed to expand laterally, the strength of the curvature is destroyed, and so goes the entire structure.

Sounds right to me!

How truly it's become an 'elastic band and duct tape' world!

Best regards
HP