8556 / 8557 Planar

SX, SLC & Ultimedia M57 SLC

rf855657.exe 8556/8557 Reference Disk v2.10 (zipped image)
   Reference disk supports SLC2/SLC3 upgrades.
rf855657_v123.zip Reference Disk v1.23 (31 Jan 1992, 10G6297) [P]
   Old version! Includes diagnostics. Cleaned up image. (thx to John Horvath)
rf8557um_v123.zip Ultimedia M57 SLC Reference Disk v1.23 (12 Dec 1991, 10G4222) [P]
   Possibly not the latest version. Includes diagnostics. (thx to John Horvath)
rf8557um_v123_alt.zip Ultimedia M57 SLC Reference Disk v1.23 [P]
   Same contents as above except for 4 bytes in the boot sector. (thx to John Horvath)
rd855657.exe 8556/8557 Advanced Diagnostics v2.04 (zipped image)

191-078 PS/2 MODEL 57 SX (8557-045 AND 049)
192-059 PS/2 ULTIMEDIA MODEL M57 SLC (8557-259)

486SLC CPU Upgrade
486SLC2 CPU Upgrade
486SLC3 CPU Upgrade
Cached CPU Upgrade

8556 / 8557 SX Planar
System Firmware
   ROM Images
Riser Cards
VRAM Functionality?

8556 / 8557 SX Planar

F3 Keyboard / Mouse fuse
J1 Mouse
J2 Keyboard
J3 Parallel Port
J4 DB25 Serial
J5 HDD-15 Video
J6 C60 External SCSI port
J7 Password-override
J9-J11 72-pin SIMM sockets
J13 Bus-adapter connector
J14 Floppy Connector
J15 SCSI connector
J17 Power-supply connector P1
J18 Control-assembly connector
J19 Power-supply connector P2
L5-L7 Filter for Video output?
LC8, LC14 ??
OS1 28.3220 MHz
OS2 41.5390 MHz
OS3 32.0000 MHz
OS4 22.1184 MHz
OS5 14.3181 MHz
OS6 25.1750 MHz
OS8 40.0000 MHz
OS9 24.0000 MHz
R149 Transorb
RT1 Resistor Termpack
U15 Sony CXK58267AM-12L
U17 85F0120
U18 Inmos IMSG171P-50
U19 Dallas DS1210S
U20 Dallas DS1285Q
U21 91F7490
U22-U25 VRAM
U28 64F4760
U30 84F7985
U35 Siemens 8032B-16
U36 92F1211
U41 121-pin upgrade/387SX socket
U52 82077AA
U55 92F1600
U58 92F1495
U59 80386SX-20
Y1 32.768 KHz

U22-U25 Toshiba TC511665Z-80H 40 pin ZIP VRAM Functionality

U41 The 121-pin PGA socket can be used to install either a CPU upgrade module or 68-pin PLCC socket for 387SX or compatible math coprocessor.

J7 has a little sticker over it that says "J18"

The 57SX supports up to 16 MB of 70 ns memory (all DMA addressable) on the planar in three SIMM sockets. The memory controller automatically supports enhanced performance via memory interleaving with all 2 MB or all 4 MB SIMMs. One, two or three 2 MB SIMMs provide memory interleaving. Two or three 4 MB SIMMs also provide memory interleaving. The 8 MB SIMMs do not provide interleaving.

Video is provided via the enhanced 16-bit industry-standard VGA.

Supports 720KB, 1.44MB and 2.88MB diskettes

System Firmware (POST & BIOS)

Firmware stored in EPROM.

ROM Images

92F1600 - Unknown date/revision, 1x Am27C2048-150JC (U55)
10G5029 - 07 Dec 1991, rev. 9, 1x Am27C2048-150JC (U55)

Riser Cards

8557SX Bus Adapter

Dotted area on J1 Solder pads for a BVE segment
J10 Solder pads for a 16 pin header
J2 AVE slot

If you have a fantasy about swapping a Lacuna riser and planar into your 57SX, forget it. The Lacuna riser has two mounting slots where the screws are both horizontal, while the 57 has a vertical screw and a horizontal screw. The lacuna mounting holes at the front don't match.

VRAM Functionality?

> This one has actual sockets installed though, not empty pads...?

Peter says:
   Yeah, most have them, and they are somewhat connected to the video-chip glue logic on the planar. But basically they are non-functional. If you look on the board you will find the same old boring Inmos RAMDAC as on Models 50/60 55/65 70/80, with limited bandwidth. Just enough for standard-VGA or 320x200 / 256 colors CGA mode. And - as said: the machine lacks the video modes in its BIOS AFAIK.

Some of the later Greenock variants of the 8556/8557 planar even lack these sockets and have only soldering spots. That was what my comment referred on.

You might however try to install some chips there for 512K and see if you can enable the mode 2Eh - that's 640 x 480 / 256 colors from a 256K palette at 60Hz vertical / 31.5 KHz horizontal. The system should choke out at Mode 12h (640 x 480 / 16 out of 256K, 60Hz / 31.5 KHz) and 13h respectively (320 x 200 / 256 out of 256K, 70Hz / 31.5KHz).

Content created and/or collected by:
Louis Ohland, Peter Wendt, David Beem, William Walsh, 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: 26 Jan 2023 - Changelog | Legal Info & Contact