Search Posts:

MITS Altair Disk 88-DCDD rev 1

SHARE

Return to Threads

  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.

Reply
  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.



Reply
  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.




Reply
  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.

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


Reply

Resources:


Buy a Commodore Computer Poster

Popular Topics and FAQs


  • Commodore B Series Tips and Tricks
  • Aerocomp TRS 80 M 1 Expansion Unit DDC
  • Items Wanted
  • Lobo Max 80
  • Zenith Z-19-CN
  • Prototype PET 2001 photo
  • Using Toggle Switches to Analyze Memory
  • Commodore Disk Archive Project
  • PET 2001 Prototype at Gametronics 1977
  • Jim Butterfield Photo
  • IMSAI 8080 With Processor Tech. Cutter
  • Secrecy is the keystone of all tyranny
  • Cromemco System Three
  • Northstar Horizon - Boot Problem
  • Computer History and Restoration Links
  • Commodore BX-256-80 - 8088 Co-processor
  • S-100 board testing with Z-80 ICE
  • Donner 3500 - an early portable computer
  • Digital (DEC) PDP 11/05 NC Assembly
  • Univac 1219 rescue
  • IMSAI 1.4 BASIC vs. MITS 8K BASIC
  • Fido BBS listing node list 6-13-1986
  • PDP 8e
  • MITS 88-2 SIO (2SIO) for BASIC
  • Visual Technology Inc Model 1050
  • Amiga 2500 Restoration
  • The Evolution Of IBM Computers
  • Replacement teletype print hammer head
  • Archiving and Copying Software 101
  • Computers Built 1940 - 1950
  • CBM B-520 (a.k.a B256-80 or B500 256)
  • RCA COSMAC Microkit
  • Commodore 64K C-116 Mods
  • MITS 8800b Turnmon 9600 baud
  • Catweasel, 8in and 5 1/4
  • Raspberry Pi as Gateway to Internet
  • Digital PDP11 late 1969 early 1970
  • PDP 11/40 72 inch cabinet model
  • PDP 11/40 Industrial 11 model
  • Digitial MicroVAX 3100 30 System
  • Digital VAX 4000-200
  • Commodore 64 / 1541 DRIVEKNOCK
  • Booting the System Using RL02 drive
  • PACS: Reflections by Kathleen Mauchly
  • Tele-Graphic Computer Systems Inc.
  • Commodore B Series SID Jukebox?
  • Installing Core into PDP 11/40
  • Setting Up OpenVMS 7.1 DNS CLERK
  • Felt-Tarrant Comptometer Model J
  • NextStation Color
  • Digital Rainbow (PC100-B2)
  • 1970 Compusad Compulogical Tutor
  • Archiving Papertapes Using DSI NC 2400
  • 1976 P.C.C. Features the MAI JOLT 6502
  • 1961 Beckman DEXTIR Computer
  • UNIVAC 1 and UNIVAC File Computer 1
  • Past Issues:


    Toshiba T1100Plus bootscrn

    This image was selected at random from the archive. Click image for more photos and files from this set.