Nothing lasts forever, but you’d think the leaded-glass face of a CRT would not be a place you’re likely to see Father Time causing failures. Alas, the particle accelerators we all lovingly stared at were very often not unitary pieces of glass: in case of implosion, safety glass was glued onto the front of the CRT. That glue will inevitably fail, as happened to the 20″ Mac-branded Triniton [Epictronics] had with a PowerPC 6100 that needed a few other repairs.
His version of cataract surgery was the most interesting. Usually cataracts are an issue for much older CRTs than the 90s-era Macintosh display featured here, but this particular display was literally pulled out of the trash and not stored well before that, so that’s probably what accounts for its accelerated aging. Usually what people do with CRT Cataracts is use heat to remove the safety glass and failing adhesive. [Epictronics] has a safer technique, however: inject fresh adhesive into the gap that’s forming around the edge of the display.
With a syringe and UV cure resin, he slowly and laboriously goes around the edge of the display to fill in the bubbles that can be reached. Luckily, the delamination on this CRT doesn’t extend very far beyond the edges, so a standard syringe tip could reach all the problem areas.
It looks good now, but if it doesn’t hold, [Epictronics] points out he can still remove the glass with the traditional hot-air technique. We hope it holds up; this is a nice technique to try if you have a CRT with the early stages of cataract delamination. For future reference, it took about one milliliter of resin to fill each square centimeter of affected area, which implies the cataract gap is quite small indeed.
Having repaired the monitor by about fifteen minutes into the video, [Epictronics] spends the remaining seventeen minutes getting the Mac running with its original CD-ROM drive (that needed recapped) and a DOS compatibility card.
We’ve featured [Epictronics] repairs here before, like when he tore down and rebuilt an IBM Model F keyboard.
is uv curable glue removable with moderate heat? interesting…
Not all, but LOCA is.
https://en.wikipedia.org/wiki/Liquid_optically_clear_adhesive
“…it took about one milliliter of resin to fill each square millimeter of affected area.”
That does not sound right. I doubt the gap was a meter deep.
I was going to complain it should be a cubed measurement, then realized that the liter is already a cubed measurement 🤦🏼♂️, so the entire sentence doesn’t really make sense, except if the point was for us to infer that the occlusions are symmetrical going from a square to a cube retaining their overall measurement.
Going back to the transcript, it should be centimeter, which implies the gap was of zero thickness. Or rather that the gap was within the tollerance of his eyeballed area measurement, I suppose.
I must have had a major brain fart when I wrote milliliter.
Err, 1ml per square cm means a 1cm gap. Not small in my book. Perhaps have a third go?
Interesting, I have an automotive tune up machine from around 1973 (think oscilloscope) that was badly delaminating. It was bad enough I could remove the glass by hand, but the glass has silkscreen markings. How hard is this to re-do if completely removed?
It should be like replacing only the glass on a smartphone screen. After completely cleaning the screen, apply LOCA ( OCA ? ) glue , then cure it with UV light. The most hard part is in avoiding bubbles, but it is doable.
“it took about one milliliter of resin to fill each square centimeter of affected area, which implies the cataract gap is quite small indeed.”
Are SI units really that hard? This statement is utterly insane.
A ml is a full cubic centimeter. 1cm by 1cm by 1cm. That means if applied over an area of one square centimeter (1cm by 1cm) it would form a layer 1cm thick. I doubt the gap between the crt and protective layer is that thick, and it would have to be even thicker if the resin weren’t spread evenly and was instead applied in specific spots.
My CRT made the mistake when of having surgery in the Valley:
“Make me look like IMAX!”