Apple IIc A2M4050 5.25” drive issue LED

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Apple IIc A2M4050 5.25” drive issue LED

Hi all,

I did a basic google search and came up empty on this topic. My A2M4050 Drive LED light for reading and writing disks does not work. The drive itself DOES work in terms of reading and writing disks without issue. I'm not sure if it is just a bad LED or if there is an issue with the circuit itself.


Here is what I have tried. I two two working Apple IIc's and one extra A2M4050 Drive that the LED does work correctly. To rule out the computer I connected the good drive to the Apple IIc in question and the drive light LED did illuminate. So I know the issue is not with the computer or disk controller. Just to double check I did plug the bad drive with no LED into the second IIc and the led did not work on it. So I believe I have isolated the problem to the drive itself.

I did not want to open the drive or attempt to make any repairs to it before seeking help. I'm hopeful,it might just be a bad led or cap but all of the forum kept pointing me to read and write issues which this drive does not have (at least not yet). I was also not able to locate any schematics for the drive. Only the disk II which I am not sure how similar they would be.


Thanks in advance.



Last seen: 41 min 46 sec ago
Joined: Jun 18 2010 - 13:54
Posts: 746
The schematic will be

The schematic will be substantially the same as the Disk II. If everything else is working, I'd suspect the LED or the connector/wiring to the analog board.

Last seen: 6 days 5 hours ago
Joined: Apr 26 2016 - 08:36
Posts: 684
A voltmeter applied to the

A voltmeter applied to the LED's leads will tell you the story.



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