68kMLA Classic Interface

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Macintosh II floppy interface doesn't work (IC chip?)

Posted by: zezba9000 on 2021-08-01 12:23:48 I have a Mac II that WAS fully working I had just cleaned and right before I put back on the lid I added a drive B cable to go out the back (for FloppyEmu). Banging my head on the wall but I shorted something while messing with the cable while power was on and now drive A or B will work. They get power but the computer doesn't detect anything was put into the disk drive. FloppyEmu also wont eject like it can't communicate with the mac. What IC chip is responsible for this? I can't seem to find it online. Could it be one of these chips? O could it be one of these?

Posted by: joshc on 2021-08-03 23:36:53 You probably toasted the IWM (Integrated Wozniak Machine) - Apple's custom disk controller chip. It's the chip at board reference at UI10 (it could be marked differently on your board depending on the revision). Getting a replacement might be a bit tricky as I cannot find any on utsource. I assume you've tried an original floppy drive as well, do those still work or also not recognised anymore? The Mac II schematics attached are useful to identify where things are and how they're connected - the floppy disk I/O is covered on page 2 of the schematics. Also refer to "Technical Introduction to the Macintosh Family" book by Apple which details how the Mac II works: https://www.vintageapple.org/macpro...nstroduction_To_The_Macintosh_Family_1987.pdf Hope this helps and good luck getting it working again!

Posted by: zezba9000 on 2021-08-05 10:30:10 Thanks I luckily found a board for parts or repair I can maybe use to fix my main board.

Posted by: LaPorta on 2021-08-05 10:41:01 Always good to have spares. Sometimes I’ll buy a complete beater, non-working machine for cheap just for the spares.

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