Model 5560

Model 5560-N Brochure (-N0B/NYB/NMB/NMY)
RICOH PS Model 5560 Brochure (-W28/W2B)

Power Supply
PS/55 Processor Complexes

General Information
5560 Planar
System Firmware
J25 Remote Power-ON Request
J28 Front Panel Connector
J31 Op Panel Connector
Model Types
SCSI Adapters
Inner View

Model 5560-N w/ CADAM keypad

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"

5560 Series Lineup (-W/N, original HERE)

Model CPU Memory
HDD Video
5561-W08/W0B/W0C 80486DX-25MHz 4MB/32MB 80-960MB PS/55 DA
5561-W18/W1B 80486SX-25MHz 4MB/32MB 80-960MB PS/55 DA
5561-W28/WA8/W2B/WAB 80486DX2-50MHz 4/32MB
(8/32MB WAx)
80-960MB PS/55 DA
5561-N0B/NYB/NMB/NMY 80486DX2-66MHz 8/32MB
(16/32MB WMx)
200-1GB PS/55 DA

5560 Planar FRU P/N 79F2592, P/N 79F0084 or 79F5496 [P] [P]

A1-4 SIMM sockets Bank A (J14-17)
B1-4 SIMM sockets Bank B (J18-J21)
BT1 Battery (CR2032)
F1 2 A fuse (keyboard/mouse 5 V)
F2 3 A fuse (floppy/DBA 5 V)
F3 5 A fuse (floppy/DBA 12 V)
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 socket
J24 Floppy connector
J25 Pads for Remote Power-ON Request
J26,27 Pads for DBA-ESDI connector
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) w/ bodge
U28 64F0942 (UART/parallel)
U30 µPD4464G-15 8Kx8 SRAM (NVRAM)
U34 Dallas DS1210 NV controller
U38 Dallas DS1285Q RTC/CMOS
U43 "SULL2" 1x9 solder pads (?)
U44 Pads for 74ALS38 (?)
U47 82077AA Floppy controller
U52 35F3798 PAL
U56 LM386 Audio op-amp (PC Speaker)
U58 Pads for 74ALS245 (op panel)
U57 "DSKBOOT" 64F3110 PAL

J7 pre-installed Japanese Display Adapter B-II or XGA-2
J12 pre-installed 2/3-length SCSI 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 sockets 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 top edge of the module and the PSU. Make sure the used modules are not too tall before you swing the PSU over the planar!

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).

J28 Front Panel Connector

Looking at the plug (female) from the front:

Pin Description Pin Description
1 Volume Control (-) 10 Volume Control (+)
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 a smaller (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: Additional components must be populated for the Op Panel to function. 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.


Model 5561
W08, W0B, W0C W18, W1B, WYA, WYB W28, W2B, WA8, WAB
Processor 486DX-25 486SX-25 486DX2-50
RAM 4MB 4MB (70 ns) 4MB (8MB for WAx)
VRAM 1MB (PS/55 Display Adapter) B-2
FDD 3.5" x1 (1.44MB/720KB)
HDD Last digit of type code indicates HD capacity (8: 80MB, B: 160MB, C: 360MB)
Option Slots (free) 32-bit full size x3, 32-bit half size x1
Storage bays (free) 2
Dimension (mm) 440 (W) x 430 (D) x 140 (H)
Weight (Kg) 14
AC Input AC 100-120V 50/60Hz, 215W (MAX)
Pre-installed OS None WYx: S/2 J2.0 & DOS J5.0 WAx: S/2 J2.0 & DOS J5.0


Model 5560-N Brochure

Model 5561
N0B NYB *1 NMB * NMY *
Processor i486DX2-66
RAM 8MB 16MB (70 ns)
VRAM 1MB (PS/55 Display Adapter) B-2?
FDD 3.5" x1 (2.88MB/1.44MB/720KB)
Option Slot (free) 32-bit full size x3, 32-bit half size x1 32-bit full size x2, 32-bit half size x1
Storage bays (free) 2
Dimension (mm) 440 (W) x 430 (D) x 140 (H)
Weight (Kg) 11.4
AC Input AC 100-125V 50/60Hz, 194W (MAX)
Pre-installed OS None 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

A 2/3-length 32-bit uncached SCSI /A adapter P/N 79F1140 was used for model -W0. The adapter has both the standard 50-pin header and the IBM card edge connector.

A stock SCSI adapter for the -W1/W2 models is a 2/3-length 32-bit SCSI/A w/ cache and a standard 50-pin header, P/N 95F4488. It uses the usual @8eff (32-bit with cache) ADF. SCSI microcode set is 64F4376/64F4377.

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 A/32 with 50-pin header was replaced with a short caching SCSI 32/A with new microcode 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)

#6: Madge Smart Ringnode MC32
#5: XGA2
#4: ACPA
#3: Intel Fax/Modem Adapter
Complex: DX2/66 Upgrade Type-B
   w/ interposer - closeup 1, closeup 2
#2: (empty)
#1: Short Cached SCSI (w/ new microcode)

Picture #2 - SIMMs and Power Connectors

You can pull the PSU forward 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 (~28 mm).

Sandy's 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 A/32 with cache, 650 MB + 1 GB hard drive, Hitachi 2x CD-ROM without bezel.

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

Ardent Tool of Capitalism is maintained by Tomáš Slavotínek.
Last update: 08 May 2024 - Changelog | About | Legal & Contact