Ardent Tool of Capitalism

Model 5550 486

51NY100.zip Reference & Diagnostic Disk for 5551-N/Y v1.00
51N101.zip Reference & Diagnostic Disk for 5551-N/Y v1.01
51N111.zip Reference & Diagnostic Disk for 5551-N/Y v1.11

3051R121.zip Reference & Diagnostic Disk for 5530-L, 5551-R/L, 5521-Y v1.21
51L110RD.zip Reference & Diagnostic Disk for 5530-L, 5551-R/L, 5521-Y v1.10
51R_fup.lzh Pentium ODP Flash Update for 5551-R v1.30
51R_dig.lzh Diagnostic Diskette for Pentium ODP 5551-R v1.24

51W113R.EXE Reference Diskette for 5551-W/W2 v1.13

General Information Model 5551-W Model 5551-N/Y    Specifications    5551-N/Y 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/L 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 5551-N Model 5551-R

General Information

5551 486 Series Lineup (-W/N/Y/L/R, original HERE)

Model 5551-W

Model 5550-W Brochure

486SX 20 MHz, 4 MB RAM standard, 28 MB maximum. 100 MB (W0A) or 200 MB (W0B) harddrive.

Model 5551-N/Y

Model 5550-N/Y Brochure

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

5551-N/Y Planar Mfg by Panasonic/Matsushita

5551-N (Socket 3 only): FRU P/N 54G1415, P/N 54G1414, "IGH0719DA"

This planar uses the same CPU support logic as the Upgrade Type-A Complex and PS/2 Model 85 "X".

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, AMD 5x86 and Cyrix 5x86-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 33 MHz (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 66 MHz. It will stop with 102 error code. My 5551-NAB has a modified BIOS ROM and it accepts 80 MHz osc (84 MHz is its limit). With the modified BIOS ROM and AMD 5x86, it runs like a champ in 160 MHz inner clock without 102 error.

Memory

72-pin SIMM socket x4. Total RAM is limited to 32MB. The planar takes FirstPage (Fast?), True Parity, 70 ns 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 by a PS/55 Japanese Display Adapter /J or XGA-2 /A according to model and type.

Riser Card FRU P/N 54G1416, P/N 54G1413

This part is commonly used for 5551-W (20 MHz) and 5551-R/L (33 MHz, 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 RS/6000 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

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 "Virginia" or "Verdy"

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

5551-R/L and 5502-L Planar Mfg by Panasonic/Matsushita

5551-R (Socket 3 only, J25-27): FRU P/N 66G1256, P/N 66G1255
5551-L (BL2 + Socket 1, J25-27): FRU P/N 66G1258, P/N 66G1257, "IGH0811EA"
5502-L (BL2 + Socket 1, no J25-27): FRU P/N 85G2639, P/N 85G2632, "IGH0849EA-Y"

This planar uses a similar CPU support logic as the Upgrade Type-A Complex and PS/2 Model 85 "X". The SYS#1 gate array is diferent - 69G1261 instead of 59G1883. Compatibility unknown.

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 AMD 5x86-133 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

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

Memory

Same as 51-N/Y. Support ECC function with true parity 70 ns 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 A/32 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 5x86 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 AMD 5x86-133 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 Cyrix 5x86 (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.