CRTs and the future of compact Mac preservation

[eldofever]

As a guy with some CRT experience, here's my 2-cents. Given the number of Macs with irrepairable cap and batt-bombed logic boards, there's no shortage of decent CRTs out there, and they remain "shelf stable" virtually forever, so I don't foresee a shortage*. The wear-out mechanism isn't necessarily bombardment of the phosphor, it's depletion of the cathode material from the heater, and it takes many 10's of thousands of hours to reach the point of an unacceptable image. Unless you're operating your compact Mac 10+ hours a day, everyday, you would be hard pressed to ever wear it out.

Now the flyback issue is a bigger problem; has anyone looked into why they fail?

*CRT rebuilding leaves the original phosphor intact and replaces only the electron gun. The last US CRT rebuilder closed in 2010, leaving only one other company, in Europe. They closed in 2013. The vintage TV collectors got together, sent a couple folks over to learn the trade, and purchased some of the equipment which was then shipped back to the US. Nothing fruitful has yet to come of this as there's still a dearth of 1940's-60's CRTs floating around out there.

 

[Phipli]

Now the flyback issue is a bigger problem; has anyone looked into why they fail?

Over heating, especially on the Plus and older. Causes a breakdown of the insulation.

Or so I understand / interpret from what people have said. Haven't had one fail myself to strip down.

Adding a fan to your plus and older would help, as would not leaving it on for long periods.

I've suggested my local interactive museum run the SE/30 all day instead of the Plus, but they just run both. Perhaps I should fan mod it for them.

 

[ClassicGuyPhilly]

Perhaps I should fan mod it for them.

Or mod up a G5 liquid cooling system

 

[eldofever]

Over heating, especially on the Plus and older. Causes a breakdown of the insulation.

Or so I understand / interpret from what people have said. Haven't had one fail myself to strip down.

Adding a fan to your plus and older would help, as would not leaving it on for long periods.

I've suggested my local interactive museum run the SE/30 all day instead of the Plus, but they just run both. Perhaps I should fan mod it for them.

I wonder if the early 128/512 machines with the elongated style flyback also have that issue? Curiously, the later flybacks seem to have been sourced from at least two different companies.

 

[LaPorta]

As odd as it may seem, I may just be crazily lucky: I have yet to have a flyback fail on me. Then again, most of my machines seem to be pretty low-time.

 

[bigmessowires]

Given the number of Macs with irrepairable cap and batt-bombed logic boards, there's no shortage of decent CRTs out there

I like the optimism but I'm not sure that follows. The 9 inch compact Macs mostly don't have the type of capacitors that leak or the type of batteries that explode. But ignoring that, if somebody did have a compact Mac with an irreparably-damaged logic board, how likely would they be to keep it around just in case they needed a spare CRT someday, versus sending the whole machine to the dump?

It's good to know the CRTs themselves will probably be OK, assuming they're not used very often. Maybe somebody will invert an open-source flyback replacement someday.

 

[Daniël]

The 9 inch compact Macs mostly don't have the type of capacitors that leak or the type of batteries that explode.

I wouldn't think that's accurate. The SE/30, Classic I and IIs have the leaking SMD caps (and there were a lot of Classics), the Classics also can have bad analog board capacitors that leak, and the Compact Macs got the explodey batteries starting with the SE. So a fairly large quantity of Compact Macs do have those faults in reality.

 

[cheesestraws]

I wonder if the early 128/512 machines with the elongated style flyback also have that issue?

The weedy original 128k flybacks self-destruct significantly more, from what I've heard. I've only got one with one in and it seems to be fine, but...

 

[Snial]

The weedy original 128k flybacks self-destruct significantly more, from what I've heard. I've only got one with one in and it seems to be fine, but...

Hang on, you have a 128k? And it didn't make it to the meet-up?!?!?!!? :-O !

 

[cheesestraws]

Hang on, you have a 128k? And it didn't make it to the meet-up?!?!?!!?

Yup, but the stuff I brought was more interesting

 

[eldofever]

I wouldn't think that's accurate. The SE/30, Classic I and IIs have the leaking SMD caps (and there were a lot of Classics), the Classics also can have bad analog board capacitors that leak, and the Compact Macs got the explodey batteries starting with the SE. So a fairly large quantity of Compact Macs do have those faults in reality.

Yeah, the SE/30 is practically the poster child for trace-eating SMD cap damage based on board layout. And I lost a spare Classic the other day due to a leaky batt. The situation is bound to get worse since it takes more effort to crack open one of these compared to popping the top on a IIcx, for example.

It's a double-edged sword, but if a guy was desperate for a CRT, all he needs to do is open his wallet. There's dozens of compact Macs for sale on ebay at any given time. Folks see the Apple logo and get dollar signs in their eyes; at least they're not hitting the dumpsters anymore.

 

[bigmessowires]

I wouldn't think that's accurate. The SE/30, Classic I and IIs have the leaking SMD caps (and there were a lot of Classics), the Classics also can have bad analog board capacitors that leak, and the Compact Macs got the explodey batteries starting with the SE.

You're right. I was thinking more about the earlier models. SE/30's and Classics especially could be a source of CRTs from Macs with dead logic boards.

 

[LaPorta]

I got a lot of six spare CRTs for free at one point. Probably good for the rest of my lifetime at least.