Flyback opinions wanted

[ktkm]

When I was trying to figure out a video problem in one of my SE/30, I noticed some cracks in the flyback (perhaps common failure these days?). As a result, the flyback gives a buzzing sound, and the glow coming from cracks pulsate synchronized to the screen distortion. The PSU is a new Stratos Hyper Rev. 4.1, and the analogue board is newly re-capped.

Should I cover up the cracks with silicon or something, or should I have the whole flyback replaced?

The flyback is a type 157-0042C, and any information regarding this type and which ones are interchangeable revisions to look out for would be truly appreciated.

 

[PB145B]

That’s definitely NOT good. Personally, I’d probably just replace it. Analog boards for the SE and SE/30 aren’t hard to come by, so it might be easiest to get a whole extra analog board to harvest a flyback from.

 

[cheesestraws]

Ooooh, is that corona discharge? Pretty. Not great, but pretty.

 

[joshc]

More than welcome to be corrected, but I don't think sealing that is safe - time for a replacement flyback I think.

 

[bdurbrow]

It should be safe to you if you use a high-voltage rated silicone. This does not, however, mean that it’s going to a) last, or b) not fry something when it inevitably does have an internal insulation breakdown.

I concur with replacing it if possible.

 

[jessenator]

I agree, unfortunately, that a replacement would be the best course. With the amount of voltage involved, I wouldn't risk it, personally.

Zoinks, but analog boards aren't cheap anymore I think I got mine for less than half this BIN just a few years ago. Though I guess the PSU is included...

Macintosh SE Analog Board 820-0206-C with Power Supply 630-0147-C | eBay

Find many great new & used options and get the best deals for Macintosh SE Analog Board 820-0206-C with Power Supply 630-0147-C at the best online prices at eBay! Free shipping for many products!

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I have a flyback from a NOS amber CRT, but I have neither an inkling of an idea, nor the technical acumen to determine if it's compatible or adaptable.

 

[dkjones96]

Fortunately they come up a lot so some decent prices can be had if you are patient. They come up WAY more than any other analog board and are much cheaper than most.

 

[davidg5678]

Zoinks, but analog boards aren't cheap anymore

The prices seem to have increased for Power Supplies as well. I bought a new SE/30 PSU for all of $9 about three years ago --they are closer to 5x that price today. I guess that's the nature of eBay!

I think that this flyback transformer definitely needs to be replaced. If you are interested, you could also look into trying to replace your internal CRT with a modern LCD panel (thus entirely eliminating the need for a flyback transformer) --I think @aeberbach is making progress with this modification.

 

[PB145B]

I quick search in the completed ebay listing shows two, one that sold for $29.99 and another for $49.95, so that’s probably the realistic going prices. $49.95 certainly isn’t “cheap,” though $29.99 seems like a good deal.

As @dkjones96 said, just keep a look out. You’ll find a deal on one eventually.

 

[ktkm]

Thank you all for your prime conclusions. I’m not going to take the easy way out. Instead, I’ll keep my eyes peeled for a replacement analogue board or a new old stock flyback transformer. I’ll start by posting my needs in the trading section, and then I’ll jump on the eBay train. Eventually, we all have to get some kind of CRT replacement, but hopefully, that is in the distant future. Thanks for the tip @davidg5678.

 

[aeberbach]

I tried sealing a flyback in a monitor that was buzzing and sparking once - it was fine for a few weeks and then one night flames started coming out!

 

[trag]

NOS flyback transformers have become difficult/pricey as well. They went from still available for about $6 each on some obscure websites about 5 years ago or so, to rare and expensive now.

 

[bdurbrow]

Eventually I think we're going to have to come up with a CRT & analog board replacement plan... perhaps a board that adapts an ATX power supply and the logic board's video output to drive a small LCD; and a 3D printable adapter & plexiglass lens to make it look kinda-sorta right. A small FPGA should be able to do that.

The only thing in common manufacture that I'm aware of that has roughly the right voltage output for the CRT anode is a laser power supply (such as is used on k40 CO2 lasers)... and I'm not sure how those would react to driving a CRT.

 

[aeberbach]

I have a replacement plan in progress - LCD screen, replacement "analog" board with no more analog, FPGA to process/display SE or SE/30 video. Depending on a board coming back this week I might be done with all the LCD power requirements and now I am writing FPGA code to manage the LCD. I've had all the bits working but in various disconnected experiments. Various things remain to be seen but I expect there will be a complete screwdriver-level solution before the year is out. Here's an image that was in the old forum's gallery section.

 

[bdurbrow]

Looks like an Altera logo on the FPGA dev board? Just curious, what's your resource utilization report from the FPGA compiler say? (just trying to get a guess on how big of an FPGA would be needed for a production board).

 

[aeberbach]

I was using an Altera but I really prefer the Xilinx tools so I switched. I'm working on an Arty A7 board (Digilent) now. Resources weren't much back then - things got harder though, I need to do clock reconstruction now to avoid having to take the 16MHz clock off the logic board. I really just want to work with pixel, vsync and hsync - those signals are available at the connector or else it doesn't just plug in without disturbing anything else. So when that's done I'll plan another board with the smallest FPGA that can handle it, and combine all the power supply stuff with the FPGA.

 

[bdurbrow]

Hmm… you could probably grab the pixel clock off the video output shift register with a wire lead that has a mini-grabber hook on the end. Might make capturing the video signal easier; and still wouldn’t be a permanent modification to the logic board…

 

[tact]

This same thing is happening to my flyback transformer and i would hate to waste money on another analog board with another old burnt out flyback that might even be worse off than the one i have! I would love to find or afford a NOS flyback or one day hopefully people will make a replacement board or lcd mod of some kind tho i would love to keep the crt going

 

[jessenator]

The talk of manufacturing new-make flyback transformers was brought up a couple of years ago

https://68kmla.org/bb/index.php?threads/worth-making-new-flyback-transformers.34706/

I would be a bit sad if the only option to be a remade board and LCD panel, but if that's the way it is what can you do?

 

[bdurbrow]

The other issue is that eventually, even if new flyback transformers could be sourced, the CRT itself is going to expire… in the old days (50’s, 60’s) there were companies that would re-manufacture CRTs, by cutting off the old neck, and putting a new one on. I think they also washed out the old phosphors and aquadag and applied a fresh coat, but I’m not sure on that.

I know that there are people making new vacuum tubes for audio applications. This is largely a by-hand operation. If a source of new phosphors could be found, I’m wondering if a similar remanufacturing process could be setup by somebody?