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80sboy

Help with Mac 128k w/upgrade

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Pretty sure this sound isn’t good. It’s a 128k with a monster Mac 2mb upgrade board with scsi.

it powers on to a checkerboard pattern and this sound. I’m not powering it on anymore, just to get a quick video. 
 

   Any and all help would be greatly appreciated - if anyone has a monster Mac 2mb upgrade and could share pictures and experiences that would be great.

tom

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Ok, removed the levco 2mb board and the machine powered up right away! Floppy works perfect and boots into finder 1.1. So, does anyone have experience with these boards? It clamps right over the 68000, I thought those had to be removed? Anyways, if anyone has a levco 2mb board jnstallled jn a 128 or 512 I’d love to hear from you as there is very little info out there on these...

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One good possibility is that the clip pins are no longer in good contact. Try adjusting them so they snug against the processor pins well.

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Yeah those Killy clips are really prone to unreliable mating after many connect/remove cycles. Ensure they are fitting snugly and press down hard to ensure the board stay put. 
 

Also ensure the upgrade board isn’t shorting out anything on the logic board. I don’t see any standoffs there?

 

By the way, nice upgrade! I’ve always wanted one of these. 

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There’s are standoffs, I got it booted up finally, I had to adjust the voltage on the analog board to come up to 5v, it was low when the upgrade board was installed, once adjusted to close to 5v it finally powered on. It’s still finicky, I think the analog board needs some love. Not sure how to tell if the upgrade is working, what OS should I be able to boot into with 2mb? I can only get up to system 4  with my floppy emu, if I try to go to system 6.0.8 it freezes.

 

   Tried a SCSI2SD on the SCSI port but it’s not getting any power, so not sure if the SCSI upgrades on these provide power at all through the pins...

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You should recap the AB. Voltages may be unstable.

Some early SCSI ports do not have termination power. So you need an external usb power for the SCSI2SD. The mac plus has the same problem with the SCSI2SD.

Edited by dochilli

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