CRTs and the future of compact Mac preservation

[bigmessowires]

The 9 inch compact Macs have mostly proven to be amazingly reliable, even as we approach the Mac's 40th birthday. But I'm hearing about more CRT problems than I used to, particularly with the flyback transformer, and I gather there's no new source for a compatible flyback replacement. Is it just a matter of time until all the compact Mac CRTs are dead? What do you think will happen then? Will some enterprising engineer launch a Kickstarter for a new flyback replacement product? Will everyone replace the CRT with a 9 inch LCD and some video conversion circuitry? Or maybe there will still be enough working flybacks to satisfy the dwindling audience of people who care?

 

[Phipli]

I gather there's no new source for a compatible flyback replacement. Is it just a matter of time until all the compact Mac CRTs are dead? What do you think will happen then? Will some enterprising engineer launch a Kickstarter for a new flyback replacement product? Will everyone replace the CRT with a 9 inch LCD and some video conversion circuitry? Or maybe there will still be enough working flybacks to satisfy the dwindling audience of people who care?

At some point it will become feasible to pay to rewind flybacks for those who absolutely must have a CRT and have no other option, everyone else will fit an LCD or equivalent. The video signal is reasonably well understood already.

I'm curious if anyone will ever design some kind of solid state flyback equivalent, but it is such high voltage it's not likely.

Ultimately the phosphor will degrade until all the monitors are so dim you can't see them and I doubt there is anything to be done about that other than replacing the tube.

 

[pizzigri]

In my case, I am trying to build a replacement AB to supply the power and function as an interface between the LB and an LCD for the Color Classic. I have a fully functional front panel that would work with a Mystic lb and another that is already perfectly working in a sort-of Takky build. For the CC, and actually the Mystic as well, the problem is that I am missing a functional edge connector from a donor AB to make it “drop-in”. The one I have is damaged. The other problem is the LCD itself. All the currently available POS type 8” color screens have a minimum resolution of 640x480, and even the best, soft of “multi sync “ models - that are &00x600 - do not scale down to the 512x384 res of the CC.
the CC CAN drive a 640x4&0 according to the original Apple schematics I got, but at a minimum needs the full VRAM installed to work. And I have no idea wether it would slow down the thing even more than the molasses hand crank operated speed it is already bogged down with.
i own two Color Classics, one of which has been ”butchered “ to make the LCD PowerCC since the Analog board died with a fried FBT. The other still works, has a Mystic inside and I left the resolution at the original 512x384 to preserve as much as possible the life of the FBT…

 

[pizzigri]

@Phipli , I believe that there was an attempt to make a minimum order from one of the last couple or three chinese transformer factories that still make FBTs for the SE 30 part, the minimum order then was around 100 pieces at 120 $ each, factoring in shipping, import taxes etc; at 1000 pieces the price was down to 89 $ each. I was never involved andI just read about it and could be mistaken. but that would mean a 12k $ investment at the very minimum.

 

[dcr]

The other problem is the LCD itself. All the currently available POS type 8” color screens have a minimum resolution of 640x480, and even the best, soft of “multi sync “ models - that are &00x600 - do not scale down to the 512x384 res of the CC.

In the interface, would there be a way to "code" it such that the 512x384 is centered on the display and the excess pixels are simply blacked out? Perhaps that would be more usable for 640x480 screens, which would leave 64 pixel margins top and bottom and 48 pixel margins on the sides. With 800x600, you'd have a lot more black margins: 144 pixels top and bottom and 108 pixels on the sides.

 

[pizzigri]

That is not something you can do at analog board level, as the driver board is still separate - what I am doing is simply routing the video signal to a VGA connector that feeds a lcd monitor. I’m cheap: I have a source of 8.2” 800x600 lcd monitors that integrate the driver board and panel for about 55 euro. They are NOS for point of sale cash registers and are quite nice however they are very limited in displayed resolutions and modes - the firmware is extremely basic. Plus, none of the separate driver boards I’ve ever seen for sale on eBay have 512x384 - they all start at 640. Short of hacking the firmware, there’s nothing you can do at the useful panel size level needed, from 7.8 to 8.2” 3/4 image form factor.

 

[cheesestraws]

In the interface, would there be a way to "code" it such that the 512x384 is centered on the display and the excess pixels are simply blacked out?

You'd basically need a custom scaler on the AB. Not impossible, but much much harder.

 

[pizzigri]

Yeep, that is it - plus, you’d be tied to a specific panel, and if the source for that panel dries up,
youre back to square one. That is why I decided to simply offer a dsub video out connector on the ab

 

[cheesestraws]

Yeep, that is it - plus, you’d be tied to a specific panel, and if the source for that panel dries up,

What I think you'd have to do is scale to HDMI at a more usual resolution, then you could use commodity driver/panel pairs. This ... could be practical if someone very good at it decided they wanted it a lot. I'm not that person, but stranger things have happened.

 

[Chuckdubuque]

There are some 8-9" LCD at 1024x768 resolution, that would scale 2X the native 512x384. Not sure if anyone has successfully done so.

 

[pizzigri]

What I think you'd have to do is scale to HDMI at a more usual resolution, then you could use commodity driver/panel pairs. This ... could be practical if someone very good at it decided they wanted it a lot. I'm not that person, but stranger things have happened.

That is SO far out of my capacity it’s not funny unfortunately…. I’d love to be able to do something like that. However it does not sound cheap either.

 

[cheesestraws]

That is SO far out of my capacity it’s not funny unfortunately…. I’d love to be able to do something like that. However it does not sound cheap either.

Mine too - the only reason I'm saying it's possible at all is that things like the OSSC exist.

 

[Unknown_K]

I figure somebody will have a OLED replacement screen that fits a compact when the need arises.

 

[Snial]

This is a classic digital archeology issue. The multiple versions of Flybacks fail (that's why my SE died in 2001, but thanks to @croissantking, I might be able to fix it in the new year). There are no DIY/Maker/Hacker replacements yet. Monochrome CRTs will fade & die, like William Harnell episodes of Dr Who and will be (as it seems right now), too expensive to recreate. Analogue boards could be replaced, we need several types, again v expensive. LCDs may be difficult to source at the right size & require some digital electronics and firmware to convert standards to VGA (which itself is dying) or HMDI.

Generating a grid of what's required to cover most bases with some half-decent future-proofing might be a good start and then we can come up with a task list for the campaign. Those Macs need liberating for future generations, it's in our remit ;-) !

 

[68kPlus]

One idea would be to pool together money from people (all kinds of Mac and other vintage computing enthusiasts) and have some kind of business (like Maceffects) place an order with a factory that makes flyback transformers (if any still exist), and then have them resold for a profit in their store, which results in the start of a new profitable market of new flyback transformers.
There's so many people in the Commodore, CRT TV, Mac etc communities that would benefit from a new flyback transformer market starting up that I can't see why this can't be done.
The only other thing is CRTs, which can't be replaced - that would probably require LCD replacements, which has already been discussed.

 

[Snial]

The only other thing is CRTs, which can't be replaced - that would probably require LCD replacements, which has already been discussed.

Since monochrome CRTs are essentially valves with a high voltage cathode and a phosphor coating, it might not be that insane to make new ones!

Build Your Own CRT TV

There was a time following the Second World War when TV sets for the nascent broadcast medium were still very expensive, but there was an ample supply of war-surplus electronic parts including ex-r…

hackaday.com

I mean... it's fairly insane, but probably not impossible .

 

[Phipli]

Since monochrome CRTs are essentially valves with a high voltage cathode and a phosphor coating, it might not be that insane to make new ones!

Build Your Own CRT TV

There was a time following the Second World War when TV sets for the nascent broadcast medium were still very expensive, but there was an ample supply of war-surplus electronic parts including ex-r…

hackaday.com

I mean... it's fairly insane, but probably not impossible .

Not at home feasibly without serious skills and capital investment.

Moulded blown glass, vacuums, sputtering, phosphors embedded contacts through glass the deflectors... The windings...

That's not a weekend hobby, there are several lifetimes of learning in there and some processes that I'd rather not expose my lungs to.

Rear projection might be easier and look similar enough. Then you just need to make a curved rear projection screen and possibly correct for the distortion.

 

[pizzigri]

A Flyback transformer can be part of a tuned circuit, so even extremely similar models cannot be exchanged (see the FBT of the 575 and the one of the CC analog boards - they differ by one last digit!) and there are as many types and kinds as there are transistors. Doubtful that a “generic“ source could be found.

 

[michimartini]

I recently discovered this spanish Producer of Flybacks, the website is weird, and you have to search for "MACINTOSH" instead of "Apple" but they seem to have flybacks at least for the Mac Plus.
Also, regarding the possible restart of CRT production: Are you guys aware that a certain Dalibor Farny has in recent years restarted production of nixie tubes? CRTs are like nixies something that will have a market again - maybe if Dalibor runs out of new nixie projects he will start making or refurbishing CRTs. A bit far fetched, i know, just wanted to throw this out there.

 

[François]

Nixies are filled with gas I think, so the glass just need to be sealed. There’s a vacuum inside a CRT, the glass needs to be much more stronger. You absolutely don’t want it to break! (CRTs were routinely tested during the manufacturing process by dropping big steel balls on them)