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My Vintage Computer Virtual Museum and blog page.

IBM PS/2 Model 25 (8525) “8086”

My IBM PS/2 Model 25 (added to my collection in 1997)

  • NEC V30 – 8mhz (originally Intel 8086)
  • 640kb RAM
  • 400MB SCSI (on IBM FRU’d Future Domain TMC-841 card with BIOS)
  • SMC 8Bit 10Base-T NIC
  • Mono MCGA graphics (320×200@8bit, 640×480@1bit)
  • MS-DOS 6.22 and Windows 3.0

I went with SCSI card and SCSI Hard drive since there are only two ISA expansion slots, The SCSI card gives the possibility of external SCSI expansion (more HDs, CD, Jaz, etc…)

I need to update the photos, they still show the 20MB ISA HardCard in place instead of the SCSI controller, and the 2nd floppy drive where the SCSI hard drive now resides.  I have also tapped the power supply lines to the motherboard to add a Molex power connector for the hard drive.



2 Comments

  1. Lorenzo says:

    Hey man, I’m curious, how did you do this?

    >> I have also tapped the power supply lines to the
    >> motherboard to add a Molex power connector for the hard drive.

    Thanks,
    Lorenzo

    • Ryan says:

      I probed the power wires with a multimeter and found which ones were +5V, +12V, and ground and tapped them and added a 4 pin molex to power the drive. When I have some free time, hopefully in the next few weeks, I will add some detailed photos of the mod.

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