Model 5550 486

Model 5551-N/Y
   Specifications
   5551-N Planar
   Rear I/O Panel
   CPU
   Memory
   Expansion Slots
   Video
   Floppy Drives
   Hard Drives
   Reference and Diagnostic Diskettes
   Chassis

Model 5551-R/L
   Specifications
   5551-R Planar
   Rear I/O Panel
   CPU
   Memory
   Video
   PSU
   Hard Drives
   Reference and Diagnostic Diskettes
   Windows 9x and 5551-R/L
   Windows 98/98SE

Model 5521-Y
   Video


Model 5551-N


Model 5551-R


Model 5551-N/Y

51-N (and Y) is SCSI model and is an IML system. Reference and Diagnostic images are stored in the system partition in a hard drive which is set to ID #6.

Features:

  • Streaming Data Transfers
  • ECC memory (not true ECC)
  • Onboard SPOCK SCSI (with 512KB cache)
  • 4-mode 3.5" floppy drive


Specifications

Model
5551
N0A
NAB
NAE
NXB
Processor
i486DX2-66 ( 8K L1 Cache, Math Co-Pro )
RAM
4MB
16MB ( ECC, 8MB x2 )
8MB ( ECC, 4MB x2 )
Disk
Drives
FDD
3.5" x1 ( 2.88MB/1.44MB/720KB )
HDD
100MB
200MB
540MB
200MB
Option Slot ( for User )
32bit full size x2 ( 1 slot is already occupied with a display adapter ) , 32bit half x 2
Interface K/B port , Mouse port, RS232C x2 ( 9pin and 25pin ), CRT port, SCSI
SCSI
Built in SCSI I/F on the planar, 512KB caching SCSI ( SPOCK ! )
Storage bay ( for user )
1
Video Sub System
PS/55 DBCS Display Adapter /J ( 1MB VRAM )
XGA-2 ( 1MB VRAM )
Kanji Font ROM 8,211 characters of JIS Level 1 and Level 2 and others.
None
Dimension/Weight
360( W ) x 415 ( D ) x 103 ( H ) mm / 9.0Kg
AC Input / PWR consump
AC100--120V 50/60Hz / 138W MAX
Pre-installed OS
None
DOS J5.0
OS/2 J2.0
DOS J5.0
OS/2 J2.0
None
5551-NMB (16MB RAM, 200MB HD, XGA-2) was equipped with OS2 J2.0 and MicroCADAM2 (CAD software).


5551-N Planar

J1 Main Power
J2 Speaker Connector
J3 MCA Riser Connector
J4 FDD Connector
J5 50 Pin SCSI Connector
J7 Power connector for optional Drives
J11 Overwrite power on pass word
J14 K/B
J15 Mouse
J16 RS232C COM1
J17 RS232C COM2
J18 Printer
J19 60 Pin SCSI Connector
J20 Power for ?
J50 Power for CPU Fan
U1 Solder Pads for 486SX33
U2 ZIF Socket
U3 10G7808 (IBM 9314PQ)
U4 59G1883
U5 59G1885
U6 33F6715
U7 15F6903
U8 84F9324
U9 10G4672
U10 95F4195
U11 N80C188XL
U13 DALLAS DS1485S
U14 M5M5256BFP-12L
U15 10G4891 (M5M27C512AFP-12)
U16 BIOS one-time PROM
U20 37G2 465F1489
U80/83 74F543D
U100 SCSI 92F2246
U101 SCSI 92F2247
Y902 OSC 66.666Mhz
Y903 OSC 66.666Mhz
Y250 OSC 32.000Mhz

Rear I/O Panel

1x parallel, 2x serial (25-pin and 9-pin), mouse, keyboard, 1x RS/6000 style SCSI connector.

Slot #1 is assigned for onboard SPOCK SCSI.

CPU

N Models
DX2-66 is loaded on a ZIF socket. Planar can take DX4ODPR-100, Am5x86 and Cyrix5x86-GP100/120/133 with an appropriate interposer with voltage regulator (VRM socket is not prepared on the planar).

Y Models
I'm not sure whether a PGA 486SX-33 is in the socket or a QFP 486SX-33 is soldered on U1. ODPDX2-66 is listed as CPU upgrade option for 51-Y.

Base clock is fixed to 33MHz (both -N/Y).
PODP can not be used on N/Y models. The socket itself can accept PODP but the BIOS doesn't support PODP. If a DX2-66 is changed to PODP, system will run, oh no, walk or crawl like a snail.

Overclocking

A stock 51-N does not accept any higher OSC other than 66MHz. It will stop with 102 error code. My 5551-NAB has a modified BIOS ROM and it accepts 80Mhz OSC (84Mhz is its limit). With the modified BIOS ROM and AMD 5x86, it runs like a champ in 160MHz inner clock without 102 error.

Memory

72-pin SIMM socket x4. Total RAM is limited to 32MB. The planar takes FirstPage (Fast?), True Parity, 70ns SIMM only (Standard Industrial Parity SIMM).
ECC/Parity selectable. You can select ECC mode in change-configuration section in reference menu using true parity SIMMs. If ECC mode is selected, system performance relatively reduces comparing to normal parity mode.

ECC function can be activated only when total RAM size in bank A and bank B are equal.
   eg 1; A1=8MB, A2=4MB, B1=8MB, B2=4MB
   eg 2; A1=8MB, A2=none, B1=4MB, B2=4MB
No need to populate SIMMs in matched pair for A1/B1 and A2/B2. But I recommend feeding 8MB sticks to all the SIMM slots.

Expansion Slots

Total 5 slots are available in a small slim body using a short height riser card. On the riser card, there are 3 slots for full length adapters on the left side (looking from the front panel) and 2 slots for half length adapters on the right side. 1 slot (left bottom) is already occupied with a PS/55 Japanese Display Adapter /J or XGA-2 /A according to model and type.

Riser card

This part is commonly used for 5551-W (20Mhz) and 5551-R/L (33Mhz, EIDE) models.

Video

No video chip is provided on the planar itself. Two types of display adapters were available:    DBCS/Display Adapter-J, FRU 07G0446 For models except below.
   XGA-2 /A 1MB, FRU 87F4744 For -NXB/NMB and -YXA
One of these adapters is loaded at slot #6 (left bottom facing to the system from the front).

Floppy Drives

4 Mode FDD: Star marked 2.88MB 4 mode drive x1.

The drive detects 2.88MB(2ED), 1.44MB(2HD), 740KB(2DD)  and 1.2MB(2HD) Japanese special mode.

Something about Japanese special 1.2 MB mode
(translated from 5551-N Quick Reference)

In order to read and write 1.2MB formatted floppy, special device drivers should be installed for DOS/V, JDOS and OS/2 2.00 and higher environment. These drivers are contained in a "Support Diskette for 1.2MB Diskette".

For DOS/V and JDOS:
Set the driver disk in A drive, move to drive A, then type install c: following to DOS prompt. Follow the installation instruction appeared on the screen.
DOS device driver $FDD35IA.SYS and format menu, FORMAT12.COM, will be installed. If you have only one FDD in your system, drive letter D and E will be assigned as 1.2MB drive. If you have two FDDs in your system, then drive letter D will be assigned to the 1st FDD and drive letter E will be assigned to the 2nd FDD as 1.2MB drive.

   $FDD35IA.SYS is in Support Diskette Ver. 1.20 and 1.21.
   $FDD35IA.SYS has been changed to $FDD12.SYS in Ver. 2.01.

OS/2 2.00 and higher:
Choose OS/2 full screen command prompt. Set the driver disk in A drive, move to drive A, then type install c: and press enter key. OS/2 device driver and format utilities will be loaded under \OS2 dir in targeted drive.

OS/2 drivers and utilities: OS2DASD.DMD, IBM1FLPY.ADD, FORMATA.COM, DISKCOPY.COM. CONFIG.SYS will be automatically amended and following two lines will be added:

BASEDEV=IBMFLPY.ADD /PS2
REM --DrvInst--BASEDEV=IBM2FLPY.ADD

FORAMTA.COM under OS/2:
Once these drivers are installed onto your system, use FORMATA.COM instead of original FORMAT.COM for formatting not only 1.2MB but also for 2.88MB, 1.44MB and 720KB. You can get detailed information in HELP menu with typing FOAMATA without parameter.

Hard Drives

Hard Drive interface (Spock)

32 bit SCSI I/F is onboard. SCSI micro code set is 92F2246/47 and bus master control code chip is 10G4891. 512KB cache is ready on the planar. One 50 pin SCSI Header (not a card edge type) is on the planar and one RS6000 style 60 pin connector is on the rear I/O panel.

I couldn't configure F/W SCSI /A, AKA Corvette along with the integrated SPOCK SCSI.

HDD

Depending on model-type, 200MB to 540MB SCSI hard drive was equipped. IML drive should be set to ID=6 and the drive capacity is limited <1GB. IBM DPES1080 can't be used as an IML drive. Actual capacity of the drive exceeds BIOS limit a bit. Conner CFP1060 might be the biggest one which can be used as an IML drive. (Actually I used it on my N). I don't know why a HDD >1GB can't be used as ID=6 though it has 46/47 micro code combo.

If you can't find appropriate drive with 1G capacity, I recommend to use a small drive for IML and choose larger drive, say 2G or something, and give ID=5 to such a drive and set it to "C drive" in set configuration (I mean "changing boot order").

Hard Drive bay

Two for 3.5" drives (The bay beside FDD is already populated with a stock SCSI HD and an optional drive bay locates below FDD).

CD-ROM Drive

Unable to install a regular CD-ROM drive within the case because a full length 5" drive will hit the PSU. If you can get a drive for laptop models with SCSI interface and an appropriate connector, and if you don't care for cosmetic appearance, maybe you can put it in the case.

Reference and Diagnostic Diskettes

Ref: Ver. 1.00/1.01/1.11 are available. Ver. 1.11 is something weird.
Diag: Ver. 1.00 for the ref 1.00/1.01.Diag Ver. 1.11 is for Ref Ver. 1.11

Chassis

Basic design for this machine was established in the model 5551-Wxx which has 486SX-20. Drive structures used in 50-W were commonly used for 51-N/Y/R/L models. It is impossible to identify model/type at a glance. You need to check the label at the left bottom of the front cover.

Pic #1
Pic #2
Pic #3

Pic #1: Top to bottom: 8570-A21, 5551-NAB, PC720 6860, PC750 6886
Pic #2: 5551-N inner view
Pic #3: PSU will swing out to right as above.


Model 5551-R/L

Appearance is completely same with 5551-N/Y except rear I/O panel. Main difference between 51-N/Y and 51-R/L is that 51-N/Y have onboard SCSI I/F and IML function while 51-R/L have E-IDE I/F and *NO* IML function (reference partition is not used for 51-R/L. "Set Configuration" should always be done with the reference diskette).

Features:

  • Streaming Data Transfers
  • ECC memory (not true ECC)
  • IDE HD interface
  • 4-mode 3.5" floppy drive


Specifications

Model
5551
R1D
RXD
RXE
RED
Processor Standard
i486DX2-66 ( 8K L1 Cache, Math-Copro )
Option
R model ; Pentium OverDrive Processor ( PODP5V83, P24T so called )
L model ; 486-33/66 Double-clock processor option
RAM
4MB
8MB ( 4MB x2 )
16MB ( 8MB x2 )
Disk
Drives
FDD
3.5" x1 ( 2.88MB/1.44MB/720KB )
HDD
340MB ( IDE )
540MB ( SCSI )
340MB ( IDE )
Option Slot ( for User )
32bit full size x2 ( 1 slot is already occupied with a display adapter ) , 32bit half x 2 *1
Interface
K/B port, Mouse port, RS232C x2 ( 9pin and 25pin ), CRT port
SCSI
None
SCSI /A -II/A 32
SCSI /A -II/A 32
Storage bay ( for user )
1
1
1
0 ( Used for CD-ROM )
Video Sub System
DBCS D/A /NI-J
XGA-2 ( 1MB VRAM )
Kanji Font ROM 8,211 characters
None
Dimension/Weight
360( W ) x 415 ( D ) x 103 ( H ) mm / 9.0Kg
AC In-put/PWR
AC100--125V 50/60Hz / 110W MAX
Pre-installed OS
DOS J5.0
PC DOS J6.1/V
none
PC DOS J6.1/V
5551-RMD (16MB RAM, 320MB IDE HD, XGA-2) was equipped with OS2 J2.1 and MCADAM/2 (CAD software).
*1 SCSI Adapter II/A32 (SPOCK SCSI with 512KB cache) is equipped for RXE and RED.
RXE: SCSI HD is hooked to the SCSI /A. Onboard IDE is left unused.
RED: 340MB IDE HD is connected to onboard IDE interface and a SCSI CD-ROM is connected to SCSI/A.


5551-R Planar

U1 Solder pads for 486DLC
U2 ZIF Socket 3 (ZIF Socket 1 for L)
U3 10G7808
U4 69G1261 SYS#1
U5 59G1885 SYS#2
U9 10G4672 I/O controller
U10 95F4195
U96 54G1412 FLASH G/A
U11 52G7656 IDE G/A
U12 N82077SL
U97 66G8422
U98 66G8423
J1 Power Connector (not used)
J2 Speaker
J3 Bus Riser connector
J4 FDD connector
J5 HD connector
J11 Overwrite power on pass word
J50 ? (solder pads only)
JMP5 ? (see 5521-Y section)
J14 KB
J15 Mouse
J16 COM1 (9-pin)
J17 COM2 (25-pin)
J18 Printer
J25 Power In
J26 Power In
J26 Power for HD/FDD
U1 Solder Pad for QFP (486-BL2)
U2 Socket 3

Rear I/O Panel

1x parallel, 2x serial (9-pin and 25-pin), mouse, keyboard.

CPU

CPU and Socket type

R planar has solder pads for 486 QFP package, and a 486DX2-66 is loaded on a ZIF socket 3.
L planar has a 486BL2-66 QFP package and has a ZIF Socket 1 just the same place where a ZIF
Socket 3 is placed on the R planar.

CPU Upgrade

5551-R is capable to run PODP5V83. BIOS should be updated to use a PODP. BIOS ROM is EEPROM (Flash ROM) and only one revision (for PODfying) was released by IBM Japan.
I think Am5x86-133 with a PowerLeap PL586 interposer is the best choice for upgrading R model.

L planar can't take a PODP because it has ZIF Socket 1 which does not fit to a POD (P24T). AMD and/or Cyrix on an interposer works fine.

Genuine Option for 5551-L
486-33/66 Double Clock Processor Option P/N 66G0727 was available.
Intel part JBOX DX2ODP66 could be used.

5551-R/L Overclocking

70MHz OSC could be used instead of 66.666MHz OSC. Any OSC higher than 70MHz will cause 102 error.

Memory

Same as 51-N/Y. Support ECC function with true parity 70ns SIMMs.

Video

Depends on machine type, two variations were available:
   PS/55 DBCS Display Adapter/NI-J FRU 54G1463 for models except below.
   XGA-2 /A 1MB FRU 87F4744 for -xXx and -xMx.

PSU

Power Supply Unit is slightly different from that of 51-N in it's dimension, but electrical specification is almost same. PSU for 51-R/L is shorter than that of 51-N/Y. R/L model has power connectors, J25 and J26, on the planar and at the same time the planar has edge connector J1 at the front right of the planar. Both connectors are electrically connected. Both 5551-R/L use AT-like power connectors on the planar.

Exception: L planar used in 5530-L lacks J25/J26 connectors. There are solder pads on L planar used in 5530-L. 5530-L uses edge connector J1 to get DC from PSU.

Hard Drives

Hard Disk Interface (EIDE) (sort of...)

R and L models have EIDE interface on the planar. I once used 8.4G 16 heads drive in my 51-R and 30-L.

51-R /L was released before EIDE specification was fixed. It could handle drive larger than 524MB. I do not know its upper limit. As far as I can see, 51R recognized a Seagate 8.4G 16 heads drive which PC750 6886 could not recognize. (The very same drive once FDISKed using 51-R could be used for 6886 but not as a primary *boot* drive but as a secondary drive).

Option:
Short SCSI Adapter II/32A with cache (microcode 44/45 and yellow DIP terminator) is equipped in 5551-RXE/RED/RMD and 5551-LEC.
Genuine SCSI CD-ROM Drive, slim and short depth, is originally equipped in RED/LEC.

Reference and Diagnostic Diskettes

Following Ref/Diag diskettes are commonly used for 5551-R/L and 5530-L.
Ref: Ver. 1.21
Diag: Ver. 1.21

In order to use a PODP in 51-R, Flash update program 5551FUP.EXE is required.
This exe file will create:
   1) Flash update diskette Ver. 1.30
   2) Diagnostic diskette Ver. 1.24

Windows 9x and 5551-R/L

  1. Unable to use genuine SCSI /A together with onboard EIDE interface. To use genuine SCSI /A, do not use any IDE devices off from the connector on the planar.
  2. If you need to use SCSI devices together with IDE devices, then choose Future Domain MCS700, Adaptec AHA-1640 and BusLogic cards. These cards can be used with it's IRQ other than 14.
  3. If you use Win98 on your 51-R/L with a genuine SCSI/A like 1. above (no IDE drives) but you have an AMD am5x86 in it, then your 51R/L will run in MS-DOS compatibility mode.

To solve this problem, replace AMD CPU to Cyrix 5x86. This symptom commonly observed on 51-N and other SCSI models using genuine IBM SCSI /A.


Windows 98/98SE

Don Peter reported that he succeeded to run Win98SE on his IML machine. But (sorry Peter) I can't believe that any of IML machine could run Win98(SE) in 32-bit disk access with built in SPOCK driver. Anyway I don't use Win98/98SE on my PS/55's. Win98 is too "heavy" for my good old PS/55's.

Additional information (2002.01.06)
Tested Win98 first edition English version on my 9585 xNx. 9585 run in MS-DOS compatibility mode with a DX4-100 and an Am5x86-133 ADZ, but with a Cyrix 5x86-100 it run in full featured mode

Am I correct?
During the test I also noticed that 9577 Bermuda (with onboard SPOCK) couldn't take a Cyrix5x86 (this is not OS matter, but the system wouldn't boot with Cyrix).

From Peter:
   "it appears to be a bug in W98 IOSUBSYS that fails to properly assign system resources on MCA machines." and "hebrew and cyrillic versions of Win98 seem to be not affected."
Click here for the original text.


Model 5521-Yxx

This model is almost same with 5551-R. CPU is degraded to i486SX-33. The most distinctive feature of 5521 is that a Cirrus GD5428 1MB SVGA /A was given for YSB and YWB models instead of PS/55 Japanese Display Adapter.

5521 Specification

  • i486SX-33MHz CPU
  • 3 mode 3.5" FDD ( 1.44MB/1.2MB/720KB )
  • DBCS DA /NI-J for Y1B and Cirrus SVGA for YSB and YWB
  • Support Streaming Data Transfer

Modified R/L planar is used for this model (QFP IBM486DL2-66 is omitted from U1). 486SX33 sits on a Socket-1 at U2. This planar has a jumper block at the location of J6 on R /L planar. According to quick reference the jumper should be turned on when a double-clock processor option is used instead of a stock 486SX33 CPU.
Double-clock processor option (P/N 66G0727) is commonly used for 5551-L, 5551-Y and 5530-L.
There are no such jumpers on these system board (At least both 51-L and 30-L has soldered QFP 486 CPUs.

Video

Cirrus GD5428 SVGA /A (adapter ID: 917A)

Cirrus GD5428 SVGA /A (1MB VRAM standard but upgradeable to 2MB) was not available as an "optional part". It's different from Cirrus SVGA used in Server 500 and is free from "flicker disease". There are solder pads for additional VRAM and the circuit is ready for adding SOJ VRAM's. Win95 built-in driver can use full 2MB but NT4 detects only 1MB.

Click here for more information about Cirrus SVGA.


PS/55 Index