8525-286 Planar

rs25286a.tg0 Model 25-286 Starter Disk v1.00 (zipped image)
25-286ad.exe Model 25-286 Advanced Diagnostics v1.0 (zipped image)

190-082 IBM PS/2 Model 25 286 (8525-006, G06, 036, G36)

8525-286 Planar
System Firmware
   ROM Images
Riser Card
Earphone Connector Board
Memory Expansion Cards

8525-286 Planar FRU P/N 64F0178, P/N 37F6675 [P]

F1 KB/Mouse fuse
J1 Mouse connector
J2 Keyboard connector
J3 Parallel port
J4 Display connector
J5 Serial port
J6 Bus-adapter connector
J7 Power-supply connector
J9,10 Dual 30-pin SIMM slots
J11 Hard-disk drive connector
J12 Diskette-drive connector
J13 Password-override connector
J14 Power-supply connector
J15 Earphone connector?
SP1 Piezo speaker
Y1 14.318 MHz osc
Y2 25.175 MHz osc
Y3 20.322 MHz osc
Y4 20 MHz osc
Y5 48.00000 MHz osc
ZM1 287-10 NPU Socket
ZM2 VLSI VL82C100 Peripheral Ctrl.
ZM3 VLSI VL82C102A Memory Ctrl.
ZM4 VLSI VL82C103A Address Buffer
ZM5 VLSI VL82C104 Data Buffer
ZM6 VLSI VL82C101B System Ctrl.
ZM9 VLSI VL16C451 Parallel/UART
ZM13 PE 21212 Delay line
ZM14 27F4094 DISKGA
ZM18 15F6864 VGA
ZM23 Inmos IMSG171P-35 RAMDAC
ZM33 Intel 8042 K/B Ctrl.
ZM35 Clock module connector
ZM36 286-10 CPU
ZM47-54 64Kx4 DRAM (VGA)

All VL82C1xx chips have "PC/AT-Compatible" in their name.

This board is very similar to the single ROM 8530-286 Planar.

System Firmware (POST & BIOS)

Firmware stored in EPROM.

ROM Images

Old Planar

30F9580 / 30F9579 - 25 Aug 1988, rev. 0, 2x 27C512 (ZM11 / ZM12)

New Planar

27F4092 - 25 Aug 1988, rev. 0, TC531024P-15 (ZM46), same as above, only combined
33F5381 - 28 Jun 1989, rev. 2, TC531024P-15 (ZM46)
33F5540 - same contents as above


30 pin SIMM 100-150 ns w. parity
Min/Max on system board: 512/4MB (16MB using adapter cards)

Riser Card

Earphone Connector Board P/N 33F4433, 57F2165, 64F0184 [P] [P]

J1 1/4-inch jack connector
L1 TDK ZJY-2P Common Mode Filter

Three conductors - Red, White, Black. The third wire is probably the PC Speaker audio line (disconnected when an audio jack is plugged in) or possibly a mute line.

More info about the Earphone Connector HERE.

Memory Expansion Cards

Limitations: The ability to use a non-IBM memory expansion card in the Model 25 286 is dependent on the flexibility of the card in establishing its starting memory address. The amount of planar memory (standard plus kits) and the corresponding starting memory address is as follows:

Planar Memory Expansion Card
Starting Address
512KB 512KB
1MB 1MB +384KB
2MB 2MB +384KB
4MB 4MB +384KB

Memory expansion cards must support the listed starting address to properly operate in a system with a given amount of planar memory.

Content created and/or collected by:
Louis Ohland, Peter Wendt, William Walsh, David Beem, Tatsuo Sunagawa, Jim Shorney, Tim Clarke, Kevin Bowling, Tomáš Slavotínek, and many others.

Ardent Tool of Capitalism - MAD Edition! is maintained by Tomáš Slavotínek.
Last update: 21 May 2022 - Changes & Credits | Legal Info & Contact