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Re: [N8VEM-S100:2278] Shugart 800 floppy drive repair


   It started while I was assembling the CBIOS for a hardware change I had made. The B: drive started reporting errors. I thought the disk itself was bad but after a few disks I was able to determine it wasn't the disks. I opened the case and cleaned the heads (q-tip and alcohol).  This didn't help. A bit of swapping of hardware left me with the conclusion it was the drive that has failed. As I was putting everything back in the original configuration I had a huge static shock; it caused my system to crash. I didn't have a clue where the static had come from. I power cycled and the system came up however I wasn't able to boot to CP/M. Being unsure if the issue was with how I had configured everything I went back to checking everything over. I then received a 2nd large static shock; I realized at this time I had left the frame ground open on the B: drive; my guess is the spinning disk was building up a static charge that I had now discharged down the floppy drive cable... twice. :(

   On power up the controller steps the head back to track 0 (a good sign) and tries to boot. I get perhaps 30 seconds on normal activity before the floppy simply stops working; at this time the heads don't step back to track 0 on reset; the heads don't load etc. After shutting it off for a bit I can repeat this cycle. My assumption is that the static shock has stressed something and that the streseds part is going thermal pretty quickly after power up. I've swapped out the FD1771 and get the same behavior. Once I find my freeze mist I'll see if I can locate the failed component(s).

   In trying to test the MSX2 card I had completely reconfigured my system; I have it back in my base configuration and everything with the exception of the floppy controller is working as expected. I have my own monitor I've slowly written over the last couple of years which works as expected. I believe the damage was isolated to the floppy controller.

   As I don't have an 8-inch alignment floppy or a drive exerciser I'm hoping to send both drives out for cleaning; alignment and repair as required.