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MITS Altair Disk 88-DCDD rev 1


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  MITS Altair Disk 88-DCDD rev 1 by Bill Degnan - 06/03/2010 18:23
The MITS Altair Disk model 88-DCDD is a single 8" disk drive. Click image for larger view.

I finally found a source to purchase working disks. Now the long journey to making a bootable system begins. In addition to the drive, I have the dual-controller cards labeled MITS Disk BD 1 Rev 0-X3 and MITS DISK#2 REV 0-X2.

more pics

NEXT: Clean the drive, get a boot loader PROM and install in my turnkey system, which I believe is the best candidate for this drive.

  Altair Disk 88-DCDD Disk Buffer by Bill Degnan - 06/07/2010 22:43
This is a cap on the disk buffer board with a leak. It still has proper voltages when tested, but should be replaced asap.

This is a cap does not have any output voltage, it needs to be replaced? I need to check the schematic.

There are two voltage regulators on the disk buffer a 7924 and a 7905. They both output to normal negative voltage levels (-23.85 and -5.04 respectively).

Drive spins when door is closed. Cleaned drive head, moderate cleaning throughout.

New pics. Note the difference in the grime from pics taken on 6/4 vs 6/7.

I also acquired docs with the disk boot loader code listing and schematic.

NEXT: Replace bad caps, locate other bad components.

  Altair 88-DCDD Perhipheral Cable Repair by Bill Degnan - 07/19/2010 23:37
The cable that connects the two 88-DCDD controller cards to the disk buffer of the drive has 4 broken wires that need to be mended. Click for larger image.

Pic 2. Click for larger image.

  MITS 88-DCDD Testing by Bill Degnan - 09/24/2013 18:25
The 88-DCDD boots a disk successfully using a separate set of drive controller cards. I cleaned the heads and exercised the stepper motor before attempting a read.

  Restoration complete by Bill Degnan - 09/25/2013 19:07
Repaired the cable, the drive controller set works, boots CP/M. Done.



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