Model 5560

Power Supply
PS/55 Processor Complexes

General Information
5560 Planar
System Firmware
J25 Remote Power-ON Request
Front Panel Connector
J31 Op Panel Connector
Model Types
SCSI Adapters
Inner View

Content created by Sandy and Major Tom.

General Information

5560-W was the first desktop model with 486 class CPU. It was introduced to the market on Oct. 1990 together with 5580-Y.

5560 is based on PS/2 Model 90 (8590/9590). It uses a similar, but not identical chassis. The planar has been redesigned, and so were some of the processor boards. The main differences are:

Photos: front, front #2, back, back PSU, short slot, inside, inside #2, -W1B w/ "kit W2B"

Model 5560-N Brochure
Also sold by RICOH as PS Model 5560 (-W brochure).

5560 Planar FRU P/N 79F2592, P/N 79F5496 [P] [P]

A1-4 SIMM sockets Bank A (J14-17)
B1-4 SIMM sockets Bank B (J18-J21)
BT1 Battery (CR2032)
F1 2A Fuse (keyboard)
F2 3A Fuse (floppy/DBA 5V)
F3 5A Fuse (floppy/DBA 12V)
J1 DB25 Serial port
J2 Parallel port
J3 Mouse port
J4 Keyboard port
J5/22 Processor Complex slot
J6 Power-on password clear
J7 32-bit MCA slot w/ BVE
J8 32-bit MCA slot w/ AVE
J9-12 32-bit MCA slot
J13,23 Power Supply connectors
J14-21 72-pin SIMM slots
J24 Floppy connector
J25 Pads for Remote Power-ON Request
J26,27 DBA ESDI solder pads
J28 Front Panel connector
J30 Fan connector (-12 V, GND)
J31 Pads for Op Panel connector
Y1 40.000 MHz osc (planar I/O bus?)
Y2 22.1148 MHz osc (UART)
Y3 32.768 KHz xtal (RTC)
Y4 14.318 MHz osc (adapters)
Y5 24.000 MHz osc (FDC)
TP1 Power Good test point
U1 65F1493 PAL
U20 57F2188 (int/KB/mouse)
U28 64F0942 (UART/parallel)
U30 µPD4464G-15 8Kx8 SRAM (NVRAM)
U34 Dallas DS1210 NV controller
U38 Dallas DS1285Q RTC
U43 N82077AA Floppy controller
U44 pads for 74ALS38 (?)
U52 35F3798 PAL
U56 LM386 Audio Op-Amp
U58 pads for 74ALS245 (op panel)
U57 "DSKBOOT" 64F3110 PAL

J7 pre-installed Japanese Display Adapter B-II or XGA-2
J12 pre-installed SCSI /A with cache adapter

Important: The original electrolytic SMD capacitors are prone to leaking! If your board is affected by this problem, you should replace the capacitors and clean the board as soon as possible. Otherwise the leaking electrolyte will inevitably destroy the board!
All 21 SMD capacitors are of the same type - 33 µF 25 V (d = 6.3 mm).
It's safe to use 16 V parts. Polymer or tantalum capacitors can be used as an alternative.

Important: The SIMM slots on the planar are not angled, which limits the SIMM height to approximately 28 mm. Most IBM modules are ~25 mm tall, which leaves only some 3 mm of clearance between the module and the PSU. Make sure the used modules are not too tall before you swing the PSU over the planar, otherwise you may damage the planar or the module!

System Firmware (POST & BIOS)

Firmware stored on the processor complex.

J25 Remote Power-ON Request (not populated)

The unpopulated header J25 can be used to turn the system on (and off) from an external source. This can be achieved by connecting pin 2 to ground (either of the remaining pins). For this to work the Op Panel must be also installed.

2-Remote Power-ON Request

Pin 2 is directly connected to pin 33 of the nearby Op Panel connector (J31, also unpopulated) and pin 8? of the Front Panel connector (J28).

Front Panel Connector

Looking at the plug (female) from the front:

Pin Description Pin Description
1 Volume Pot (-) 10 Volume Pot (+)
2 PWR LED (-) 9 PWR LED (+)
3 HD LED (+) 8 PWR Switch (+)
4 HD LED (-) 7 Speaker (-)
5 PWR Switch (-) 6 Speaker (+)

Note: The pin numbering is made up. The PCB has the pins marked incorrectly on the silkscreen (duplicate numbers).

The volume pot is 10 KΩ (linear?) with a middle position detent.

J31 Op Panel Connector (not populated)

Provides similar functionality as the Model 95 Op Panel header, the pinout is different however. It was likely to be used together with the Front Panel header (J28), but only with 2x8-pin connector populated (J28 and J31 partially overlap - both physically and functionally).

Pin Description Pin Description
1 Ground 2 Data 0
3 Ground 4 Data 1
5 Ground 6 Data 2
7 Ground 8 Data 3
9 Ground 10 Data 4
11 Ground 12 Data 5
13 Ground 14 Data 6
15 Ground 16 Address 0
17 Ground 18 Address 1
19 Ground 20 -Write LED (low or high?)
21 Ground 22 -Write LED (low or high?)
23 Ground 24 +5 V
25 Ground 26 +5 V
27 Ground 28 +5 V
29 -Power-ON Request 30 +5 V
31 Ground 32 Volume Control (J28 pin 10)
33 -Remote Power-ON Request 34 Ground

Note: Some other components must be populated to make the Op Panel functional - at the very least U58 (74ALS245) and possibly some other.

Processor Complexes

60-W0x Complex (486DX 25 MHz)
60-W1x/W2x Complex (486SX 25 MHz / 486DX2 50 MHz)
N / DX2-66 Upgrade Type-B Complex (486DX2 66 MHz)

Model Types

As described HERE there are 4 types of 5560:

  • 5561-W0x - 486DX-25: If you have filled all SIMM sockets with 8 MB SIMMs, you'll have enough time for cigarettes and a cup of coffee (or two) until the machine finishes the memory count.
  • 5561-W1x - 486SX-25: Faster memory count than -W0x.
  • 5561-W2x - 486DX2-50: Most likely the same complex as in -W1x.
  • 5561-Nxx - 486DX2-66: Supercharged 5560 with a Type-B DX2-66 upgrade platform.


W08, W0B, W0C
W18, W1B, WYA, WYB
W28, W2B, WA8, WAB
4MB (70 ns)
4MB (8MB for WAx)
1MB (PS/55 Display Adapter) B-2
3.5" x1 (1.44MB/720KB)
Last digit of type code indicates HD capacity (8; 80MB, B; 160MB, C; 360MB)
Option Slots (free)
32bit full size x3, 32bit half size x1
Storage bays (free)
Dimension (mm)
440 (W) x 430 (D) x 140 (H)
Weight (Kg)
AC Input
AC100--120V 50/60Hz, 215W (MAX)
OS installed
WYx; S/2 J2.0 & DOS J5.0 WAx; S/2 J2.0 & DOS J5.0


Model 5560-N Brochure

NYB *1
16MB (70 ns)
1MB (PS/55 Display Adapter) B-2 ?
3.5" x1 (2.88MB/1.44MB/720KB)
Option Slot (free) 32bit full size x3, 32bit half size x1 32bit full size x2, 32bit half size x1
Storage bays (free)
Dimension (mm)
440 (W) x 430 (D) x 140 (H)
Weight (Kg)
AC Input
AC100--125V 50/60Hz, 194W (MAX)
OS installed
OS/2 J2.0 & DOS J5.0 OS/2 J2.0 & MCADAM OS/2 J2.0 & MCADAM

*1 NYB : OS/2 model
*2 NMB : MCADAM/2 (CAD software) included. ASYNC TTL /Adapter is included.
*3 NMY : MCADAM/2 upgrade version. ASYNC TTL/Adapter is included.


8 x 72-pin SIMM sockets mounted directly on the planar.
Parity 8 MB/70 ns SIMMs are mandatory for -W1, -W2 and -N complex.
For W0 complex, 80 ns SIMMs are standard, and must be used in matched pair.
For W0/W1 models, reference ver. 1.11 is required to use more than 16 MB of RAM.


No video on the planar.
32-bit BVE slot with PS/55 Display Adapter B-2 or XGA-2 installed.
32-bit AVE slot available.

SCSI Adapters

Uncached 16-bit SCSI /A was used for model -W0, but I don't know if it was the long or short version.

A stock SCSI /A for -W1/W2 models is a 2/3-length 32-bit adapter with a standard 50-pin header. It uses the usual @8eff (32-bit with cache) ADF. SCSI microcode set is 64F4376/64F4377. More info HERE.

Model 5560-N was equipped with a short SCSI Adapter II/A (32-bit) with 512 KB cache (marked as 06G6760 in sales leaflets, and I think it's either 35G2818 or 07G3063).

Inner View

Photos below are inner view of my 5561-W1B with Type-B Upgrade processor complex installed. Half-sized cached SCSI /32A with 50-pin header was replaced with a short caching SCSI /A -II/32A with new micro code set.

You can see an AMD 5x86-133 CPU on an interposer with a low-profile heatsink. The CPU runs at 160 MHz (internal). No CPU fan, but the front fan blows a fresh air over the heatsink.

Picture #1 - Adapters (top to bottom)

J9: Madge Smart Ringnode MC32
J7: XGA2
J8: Intel Fax/Modem Adapter
J5: Processor complex DX2/66 Upgrade Type-B
   w/ interposer - closeup 1, closeup 2
J11: (empty)
J12: Short Cached SCSI with new Microcode

Picture #2 - SIMMs and Power Connectors

You can pull the PSU up and then swing it to right side, similar to Model 95.

Notice how different the power connections are when compared to Model 90.

Tall SIMMs are not good for 5560. There isn't much space between the SIMM slots and the PSU.

My 5561-W1x (upgraded with 60-N complex)

64 MB of RAM, BIOS modified N complex with 80 MHz OSC, AMD 5x86 running x4 speed, ATI-GUP, Madge Ringnode MC32, Genuine IBM SCSI /32A with cache, 650 MB + 1 GB hard drive, Hitachi 2x CD-ROM without bezel.

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: 19 Nov 2021 - Changes & Credits | Legal Info & Contact