Mac Plus Power Supply Modifications

[MacTech68]

The only simple (cheap) video out I'm aware of requires a TTL capable monitor that can easily handle 22Khz. Also a rather rare/old beast.

See section "9.1.1 Monitors" on page 24 of the previously posted PDF.

I wish I had never thrown so many 128, 512 & Pluses away so many years ago. ?

 

[theminidriver]

Cool, thanks. I've also seen some conversions to composite -> VGA. Will see.

Wow - I've never seen a 128k or 512k. My Plus is the only one I've ever seen in real life. Macs never caught on as a consumer machine in South Africa in those days. They were only used a bit in the printing industry, and only really from the Macintosh II onwards.

I do regret throwing out a couple Sinclair Spectrums back in the day tho!

 

[theminidriver]

The saga continues even further! I was lucky enough to have a trip to the USA, and I picked up a flyback from the link earlier in the thread ( 157-026C Flyback 157026C / Replaces Apple / HR 42031 | eBay ).

It fixed it a bit - the screen is not shaking and is legible, except there is a bright vertical band on the left hand side of the screen. And Q3 (US) BU406 gets really really hot.

I tried changing it (could only find a BU406G, not sure if materially different). But that had the effect that there was no beep, and the display kinda collapsed into a very thin squiggly line, and the BU406G got even hotter than the one it replaced.

So I've changed back to the original BU406, and it reverted to the previous behaviour.

Any clues welcome! Thanks!

 

[aihk]

After much recapping, reversing modifications, replacing all diodes and rectifiers, and basically refurbing the whole power supply and floppy drive, we finally have victory! Just need to get a small gear 3D printed for the floppy auto-eject, and she will be as good as new! Thanks for all the info and tips

View attachment 1940895

Hello ~ My Maikinsa's voice is the same as you are. What are you resurrected after changing?

 

[pete1]

The saga continues even further! I was lucky enough to have a trip to the USA, and I picked up a flyback from the link earlier in the thread ( 157-026C Flyback 157026C / Replaces Apple / HR 42031 | eBay ).

It fixed it a bit - the screen is not shaking and is legible, except there is a bright vertical band on the left hand side of the screen. And Q3 (US) BU406 gets really really hot.

Did you have any luck fixing the vertical band? I have this on my SE/30 - although much fainter than yours, it's in the same position.

 

[theminidriver]

Sorry to hear.
Unfortunately, no cure, it just got hotter and screen started shaking and then completely dead. At a loss at this point really.

 

[pete1]

Here's a pic. Luckily the machine doesn't seem to be getting worse or anything like this. It came up after a full recap of the analog board plus a reflow, so I'll need to check over my joints.