68kMLA Classic Interface

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Interchangable flybacks? Mac Plus and Mac Classic

Posted by: dehij on 2022-01-30 13:13:08

Hi all,
My Macintosh Plus is making the repeating flup flup sound and not powering on, and upon inspection, the flyback is physically damaged (the metal rod has been corroded in half). I've never seen it working. I recently got a Macintosh Classic with a bad analog board and logic board, I was wondering, are the flyback transformers the same spec between the two? They look pretty similair.
Maybe the flup sound has nothing to do with the broken flyback, but it looks pretty dangerous. This is why I'd like to repair the flyback first before attempting any other repairs.

Posted by: bibilit on 2022-01-31 08:18:38

Not the same.

Posted by: marcelv on 2022-02-01 08:49:18

flup flup can have multiple causes.
Could you add a picture of the flyback ?

can check if I have a flyback to test or assist in troubleshooting (location NL)

Posted by: dehij on 2022-02-03 13:20:47

flup flup can have multiple causes.
Could you add a picture of the flyback ?

can check if I have a flyback to test or assist in troubleshooting (location NL)

Model 157-0026-B

I've read through The Dead Mac Scrolls, which indicates the problem does not have to do with the flyback in my case.

Posted by: marcelv on 2022-02-03 15:31:09

240v Power circuit

Hi all, Does anyone know of a version of this doc (especially the power circuit section) for the 240v international board for the 512k Analog board ? I am still trying to diagnose a flup flup issue.

68kmla.org

Posted by: dehij on 2022-02-03 22:41:46

240v Power circuit

Hi all, Does anyone know of a version of this doc (especially the power circuit section) for the 240v international board for the 512k Analog board ? I am still trying to diagnose a flup flup issue.

68kmla.org

Thanks!

Posted by: Cinan on 2022-06-17 05:31:54

did you end up fixing this Dehij ?

Posted by: dehij on 2022-06-20 07:06:13

did you end up fixing this Dehij ?

Nope, I was busy with other projects.

Posted by: 360alaska on 2022-11-28 22:07:20

Pretty sure they are the same if you have a REV 1 classic analog Board, rev 2 analog board have a square looking unit.

Posted by: techknight on 2022-12-01 06:58:27

Model 157-0026-B

I've read through The Dead Mac Scrolls, which indicates the problem does not have to do with the flyback in my case.

Yeah that is a problem. If that clamp breaks, it throws off the core gap so that flyback will never work properly, if at al, again.

Posted by: dehij on 2023-02-16 08:26:38

Pretty sure they are the same if you have a REV 1 classic analog Board, rev 2 analog board have a square looking unit.

Thanks! I'll see.

Yeah that is a problem. If that clamp breaks, it throws off the core gap so that flyback will never work properly, if at al, again.

Thought it'd be a problem. Is it okay to test the Macintosh like this, to first fix the flup flup issue, and then fix the flyback? Is the clamp being in half like this dangerous? Any way for an arc to form between the two halves?

Posted by: mst3k on 2024-09-17 05:52:16

Can I use a flyback from a Mac Classic AB on a Mac 512k AB?
Pinouts are the same. Perfect fit.

Not the same.

Pretty sure they are the same if you have a REV 1 classic analog Board, rev 2 analog board have a square looking unit.

Not sure if it's safe to throw the switch...
Thanks

Posted by: mst3k on 2024-09-17 07:23:17

A bit more info.

The donor board:

The new home:

The Flyback: