Apple IIc+ Disk Problem

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Last seen: 1 year 11 months ago
Joined: Jun 28 2018 - 23:01
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Apple IIc+ Disk Problem

I'm working with a user in Europe to debug an Apple IIc+ that he purchased from me. When I had it, it powered up and generated video, but the disk operation was untested. It had been in storage for an extended period of time, and I never had any disks for it to use for testing.

His report of the current status is:

General test does not show anything, but this won't show up any drive related problems, just memory/processor. Switching from turbo (4Mhz) to normal (1Mhz) mode works. Keyboard works. Drive and external drive connector do not work. Even replacing the drive by Floppyemu or connecting external drive is not solution - it should work even with failure of internal drive but this does not work.

I am looking for any suggestions for anything else that he can try. Since the failure seems to affect both the internal drive as well as the external connector, that seems like something fairly major is not working.

Any ideas would be appreciated. Thank you ... Dave

Last seen: 1 year 9 months ago
Joined: Jan 4 2018 - 06:57
Posts: 0
thx Dave for putting the case

thx Dave for putting the case here, hope to find solution or answer to the problem.

What I have already checked:
- system selftest shows ok but it doesnot use floppy drive for any test, so probably RAM only tests are performed.
- I have 2x A9M0106 (3,5") and 2x A9M0107 (5,25") that works perfectly with Apple IIGS and none of these drives even ping activity with this IIc+
- Floppyemu shows no activity with both external and internal connection - or any Apple II 3,5/5,25" simulation

The internal drive arrived with mechanical failure - cannot put floppy disk inside, something is bend and broken inside, but disconnecting drive doesnot change anything. I have connected floppyemu to the internal connector on the board - result is the same - it doesnot work.

I'm a little frustrated with situation as it looks like failure of the MIG chipset and/or its SRAM memory on the board. Nothing else explains why external and internal connection doesnot work with these all 5 drives.

Internal floppy can be replaced but replacing this chipset can be a big problem as donor boards almost not exist. Am I wrong folks?

Last seen: 3 weeks 14 hours ago
Joined: Apr 24 2012 - 17:03
Posts: 261
Sounds like several issues,

Sounds like several issues, shame you are in Europe as people who can try to help are scarce. Try switching the internal 3.5 with the external mechanism. Also reseat all chips. Would work to try another ROM but may be hard to get. Really you need to send it to somebody to diagnose and swap chips to find the issue. I fixed a very damaged //c+ by swapping chips and finding a RAM chip to be the culprit.
Unfortunately if the seller told you it was untested there's not much you could do.

Last seen: 1 year 9 months ago
Joined: Jan 4 2018 - 06:57
Posts: 0
javster, I have solved the

javster, I have solved the problem by replacing two chips including VLSI and RAM. Until that swapping internal and external, including Floppyemu was giving no progress. I was lucky to pick broken (literally) Apple IIc+ board here to take only two chips from it. So I have it now working!

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