rf855657.exe 8556/8557 Reference Disk v2.10 (zipped image)
rd855657.exe 8556/8557 Advanced Diagnostics v2.04 (zipped image)
Reference disk supports SLC2/SLC3 upgrades.
191-078 PS/2 MODEL 57 SX (8557-045 AND 049)
486SLC CPU Upgrade
486SLC2 CPU Upgrade
486SLC3 CPU Upgrade
Cached CPU Upgrade
8556 / 8557 SX Planar
8556 / 8557 SX Planar
F3 Keyboard / Mouse fuse
J3 Parallel Port
J4 DB25 Serial
J5 HDD-15 Video
J6 C60 External SCSI port
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
RT1 Resistor Termpack
U15 Sony CXK58267AM-12L
U18 Inmos IMSG171P-50
U19 Dallas DS1210S
U20 Dallas DS1285Q
U35 Siemens 8032B-16
U41 121-pin upgrade/387SX socket
Y1 32.768 KHz
U22-U25 Toshiba TC511665Z-80H 40 pin ZIP VRAM
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
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.
92F1600 - Unknown date/revision, 1x Am27C2048-150JC (U55)
10G5029 - 07 Dec 1991, rev. 9, 1x Am27C2048-150JC (U55)
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.
> This one has actual sockets installed though, not empty pads...?
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
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).