rfp75a.exe P75 486 Reference Disk v1.0 (zipped image)
190-197 8573-P75 486 (8573-161 AND 8573-401)
SHS84F8525 IBM PS/2 P75 486 HMR
SHS84F7593 IBM PS/2 Model P75 486 HMS
tpvol1.pdf HMM for IBM PS/2 P70/P75 and laptops/notebooks
Patched Refdisk Files
(result of running XGAOPT on original refdisk)
P75 Errors
P75 Processor Card Mods
Failing Capacitors (14902 Error or just no video at all)
IBM PS/2 Portable Restoration (biesenhome.de)
The Fastest Portable: IBM's P75 Road Warrior (BYTE article)
P75 System Board
Indicator Port Pinout (J17)
Slot Numbers and Widths
Memory
Filling SIMM Sockets
Non-OEM Memory
64MB in a P75?
Actions On Memory Errors
Processor Card
Video Card
J1 and J2 Function
Battery Pack
Floppy Drive
Floppy Controller
2.88MB Capable?
Attempting 2.88MB
Support (Always use the stock refdisk!)
Undorking a P75
External Storage Device Connector
External Storage Device Cable Source
Remove Floppy Drive (H1 Model)
Reassemble Floppy Drive
P75 SCSI
Terminators
Remove SCSI BIOS Chips
SCSI and System BIOS Wondering
Set SCSI ID
SCSI Cable
P75 Drive Carrier Screw Spacings
P75 HD Rail Dimensions
Hard Drive Mounting Rails
Hard Drive Mounted in Cage
Brightness Program
P75.EXE
Active Matrix LED Screen Prototype
Riser Swap with P70
Windows 98SE
Built-in Features ADF
Some photos sourced from biesenhome.de.
P75 Planar "IGH0445FA", FRU P/N 78F9896, P/N 78F9894 (Japanese design)

15F OKI 15F7917
4464 Hitachi 4464S-08LL
82077 82077AA Floppy Controller
8032 80C32-1 MCU (SCSI)
Even 79F3214 SCSI BIOS Even
Odd 79F3213 SCSI BIOS Odd
F1-3 Little Fuse 1.5A picofuse
F4 LF unk Amperage Fuse for floppy
GA2 64F8781
GA3 79F3196
GA4 79F3242
GA5 79F3202
I7 Hitachi 4464S-08LL
I56 79F3200
IC5F 90X8134(ESD) DMA Controller
J1 Keyboard
J2 Mouse
J3 Printer
J4 RS232C DB25
J5 External Floppy
J6 Display
J7 Bus riser
J8 PSU
|
J9-12 72-pin SIMM socket (SIMM1-4)
J13 SCSI internal
J14 External SCSI C60
J15 Speaker
J16 Floppy
J17 Indicator
J19 Processor
J20 MC-2
J21 HDD Power
JP1 Power On Password
MC146818 MC146818AF
SCSI3 OKI 33F6910
SCSI7 33F6715
SI 5-pin header outline, "SCSI ID"
TP 8-pin Term Packs IR6-8
uCode P/N 79F3212
X1 20.0000 MHz osc
X2 32.768kHz? xtal
X3 14.31 MHz osc
X4 24.0000 MHz osc
X5 20000 xtal ?KHz
X6 12500 xtal ?KHz
|
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!
More information HERE.
J17 six pin header for
floppy drive, power, and hard drive LEDs
J20 MC-2 14 pin
header that connects to riser card.
J8 Wire Colors
Pin1 on left, pin 10 on right (silkscreened on
board)
Blue (9), Orange (10), Red (11), R (12), R (5), Black
(8), Bk (1), Bk (2), Bk (3), White (4). Numbers in ( )
are the corresponding power supply connector.
Indicator
Port (J17) Pinout
This is the Indicator port- three LEDs are
driven off this header, Power, HD, and Floppy. Note that
the header on the system board and the display card (P/N
65X1569) are keyed, so the pins match from 1 to 1, 2 to
2, and so forth.
Pin LED
1-2 Power LED
3-4 HD LED
5-6 FDD
Slot Numbers and Widths
The two upper slots are 32-bit. The slot next to the rear cover has the AVE
connector. The bottom two slots are 16-bit, and they are short. FWIW, Slot 1 is
the internal SCSI controller.
|
Slot 4 (Outer Top) 32-bit MCA w/ AVE
Slot 2 (Inner Top) 32-bit MCA w/ MME
Slot 3 (Inner Bottom) 16-bit MCA
Slot 5 (Outer Bottom) 16-bit MCA
Memory expansion cards in Slot 2!
|
Memory
2 and 4 MB 70 ns parity SIMMs are supported, max 16 MB on the planar.

Panasonic OEM (IGH0380BA)
4MB is FRU 64F3605 P/N 64F8776
IBM 4MB FRU 92F0105 P/N 71F7010
FRU 6450128, 927200 are 4MB SIMMs from IBM,
the P75 is somewhat sensitive to positioning them, so
you may have to move them around until it works.
64F3605 and 92F0105 Considerations
Memory "Manufactured by IBM" 4MB 70 ns memory,
FRU P/N 64F3605 or P/N 92F0105 and 2MB 70 ns memory
FRU P/N 64F3604, or P/N 92F0102 will operate in
the odd memory sockets (J9 and J11) on the 8573-P75
system. The "Manufactured by IBM" 4MB 70 ns SIMMs
has nine (9) memory modules placed vertically on one
side of the SIMM.This is due to a timing line
incompatibility problem between the system board and
"Manufactured by IBM" memory. If this memory is
installed in the even number memory sockets, POST error
codes or advanced diagnostics errors such as 107, 110
with five question marks, 215, 216, or 221 can occur.
Memory "Manufactured
for IBM" has the same FRU number but has either
eight vertical and four horizontal modules on one side
of the SIMM, or it may have modules on both sides of the
SIMM. Memory "Manufactured for IBM" does not have a
socket restriction and can be installed in ODD or EVEN
system memory sockets.
Update:
A new 4Mb SIMM FRU P/N79F3234 is now available for use on the 8573 P75 systems.
This SIMM operates in all system board memory locations.
Memory "Manufactured by IBM" is now
used as FRU stock for the 8590 and 8595. It is
used as OPTION STOCK for the 8573 P75, 8590 and 8595.
but for the 8573-P75, it is only to be installed in the
ODD sockets. The 8590 and 8595 can use either "Manufactured by
IBM" or "Manufactured for IBM" in ANY memory socket.
Thinkpad General - Model P70
And P75 Memory Checkout
Applicable to: World-Wide
Memory Checkout: Power-off computer before removing or
replacing parts.
4MB memory modules installed in slots 2 or 4 must be FRU
79F3234.
Filling SIMM Sockets
When you expand the memory capacity with
2MB or 4MB SIMMs, use one of the following arrangements.
Other combinations makes the access times slower. (IBM
P75 Quick Ref, Pg. 20)
SIMM |
OEM |
1 |
2 |
3 |
4 |
5 |
1 |
4MB |
4MB |
4MB |
4MB |
4MB |
4MB |
2 |
4MB |
4MB |
4MB |
4MB |
4MB |
4MB |
3 |
|
2MB |
2MB |
4MB |
4MB |
4MB |
4 |
|
|
2MB |
|
4MB |
2MB |
Total |
8MB |
10MB |
12MB |
12MB |
16MB |
14MB |
Non-OEM
Memory
From Me
What about dumping 4x4MB sticks in my P75?
Yeah, get some!... What an education! First, I
dumped in 4 70 ns PS/2 SIMMs. 201/110 error. Swapped out
#3 chip, cuz it barfed at about 1200KB. Didn't do it.
Swapped out the last two 4MB SIMMs with the original BIG
4MB SIMMs. Barf at 8000KB.
Well hell, I swapped the original SIMMs
into MEM1 and 2, put two PS/2 SIMMs in 3&4. Counts
it, it boots. I think it's happy. Odd, does the P75 have
special mojo on the original SIMMs or what?
64MB on a P75
Ivar Amund Grimstad wrote:
I have upgraded to a total of 64MB RAM, using 12MB
on the planar and 52MB on a Kingston KTM-MC64 expansion
board that fits only in the upper 32-bit slot.
(Ed. I think there has to be
a "memory window" in the 16MB so you can "map" the
extended memory into it. Might be able to get 14MB on the
planar with 4x4x4x2?) (Ed.
Slot 2 is the MME slot)
Peter said:
>According to Peter, he's running a later Acculogic
SIMMply Ram that can utilizes four 8 Mb 72 pin parity
SIMMs with only 8 Mb (two 4 Mb SIMMs installed on the
planar) for a total of 40 Mb.
That's right. The P75 is -more or less- a
"Model 90 with a carrying handle". So the 16MB memory
limit does not directly apply on that machine (unlike to
Mod. 70 and 80). However: the planar memory mapper seems
to be a bit odd and needs to map in the memory on a card
("Channel Memory") into the lower 16MB to have it
addressable. That's why I had to remove memory from the
systemboard.
Interesting in this respect was the fact
that I had to remove 4MB when the Acculogic was equipped
with 4 x 4MB modules and I had to remove 8MB from the
planar, when it had 4 x 8MB. Seems as if the memory
granularity only adjusts to full module values (4 or
8MB).
Action on Memory Error
The P75 allocates memory in 2MB blocks,
except for the first 2MB of system-board memory. For
errors in this first block, the following occurs:
Error in First 512KB
If POST detects an error in the first
521K of system-board memory, the first 2MB block of
system board memory is deactivated and the following
occurs:
° If an
additional 2MB block of system board memory is
installed, the addresses assigned to the deactivated
block are reassigned to the second block of sbm. This is
only true for the first two 2MB blocks of system board
memory. After the first two blocks, an error code is
displayed.
°
If additional system board memory is not
installed, no address reassignment occurs and an error
code is displayed.
° The first
512KB of memory address space cannot be assigned to
adapter memory.
Error Outside First 512KB
If POST detects a memory error in any
memory after the first 512KB of system board memory, the
2MB block of memory is not deactivated and an error code
is displayed. In this event, the customer level
diagnostics program can be run to deactivate the 2MB
block and reassign the addresses.
After the block is reassigned, the
defective block is ignored by POST during subsequent
power-ons.
If errors occur one at a time, the system
deactivates 2MB blocks of memory. However, if two errors
occur at the same time on the same SIMM, the system
programs cannot be loaded and an error message is
displayed.
Processor Card "iGH0377CA", FRU P/N 64F8789, P/N 64F8775 (Japanese design)
|
IC5 486DX-33 CPU (soldered!)
OSC1 66.6666 MHz osc
ROM 64F9924 (soldered!)
Plus some 74xx glue logic. Very simple board.
P75 CPU Upgrade (from Jim Shorney's site)
Jim Shorney's P75 Wizardry (documented by MAD Max)
|
Video Card "IGH0446FA", FRU P/N 78F9897, P/N 78F9895 (Japanese design)

44256 Hitachi 44256S-10LL
CN1 Plasma panel
CN2 External video
CRTC32 TC110GC9AG
DAC32 37F0842
J1,2 POS ID (see HERE)
PDPC 53F8674
|
TC524256 Toshiba TC524256J-10
VRAM Toshiba TC524256AZ-10
Y1 25.175 MHz pixel clock (640x4xx)
Y2 41.539 MHz pixel clock (132-column)
Y3 28.322 MHz VGA / Text mode
Y4 44.900 MHz pixel clock (1024x768i)
Y5 40.000 MHz DMA Clock / 2
|
A lot of these are used on the XGA
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!
More information HERE.
J1 and J2 Function
Both J1 and J2 are jumpered on 2-3.
WBST:
An update on those mysterious jumpers (J1-J2) at the
top of the adapter. These apparently control the lowest
2 bits of the Adapter ID read during planar POS setup.
With them both off entirely, the Adapter ID was read as
8DFF. With them both on 2-3 the Adapter ID was read as
8DFB (XGA). I'd guess that the 1-2 position serves
solely as a storage position.
POSID |
8DFF |
* |
8DFB |
J1 |
Open |
1-2 |
2-3 |
J2 |
Open |
1-2 |
2-3 |
* Storage position
Similar functions may also apply to those on the P70
video display adapters, possibly modifying the VGA
adapter ID (EFFD) in a similar manner.
Perhaps the multi-XGA class adapter design work started
with the VGA class adapter standard?
Battery Pack PN 79F3198 (assembly),
Battery Card PN 64F8794
The P75 uses a 6V battery pack, with two Panasonic
CR2477 3v 1000 mAh cells in series soldered to a circuit
board.
|
The battery header (J18) is a four pin header with
one pin missing. The plug on the end of the battery card
cable has one position plugged.
|
J18 Pinout
|
Battery Card plug 3 is Black, 1 is Red, 2 is NC.
The battery card socket has a plastic plug in the
position of the missing pin.
|
Floppy
Drive
The floppy can be used
in the open or closed position. It is recommended that
it is operated in the closed position so the chance
of foreign material dropping in the drive is
greatly reduced.
The floppy in my P75 is a ALPS DFP723D15C, 12v .47A, 5v .16A
Floppy Controller
It's a 82077AA. Probably supports 2.88MB floppy
drives (yea! got to love the dust shutter), but NOT the
" * " marked 2.88MB
floppy drives.
2.88MB
Capable BIOS?
This is from the HMM- note the reference to a "4MB Media
Sensor"....
3.5-Inch Diskette Drive 38F5936
3.5-Inch Diskette Drive 38F5936 (with 4MB
Sensor)
Using the 2.88MB Floppy
According to the Western Gunslinger, David
Beem, the non-star 2.88 works. So I whipped out a FRU
64F4148, Sony MP-F40W-03, and dropped it in with some
trepidation.
Installation- This
model has the same layout as the original ALPS
DFP723D15C. Looking from above, the drive motor is on
the left (same side as the eject button) and floppy
cable is on the right.
Note: After some
thought, the cable tie holding the floppy cable to the
bracket on the PSU is most likely to assist in
positioning the floppy header during assembly. It is
possible that carefully cutting the cable tie would
allow you to use a 2.88MB floppy with the 34 pin header
on either side...
Just swap the plasticized shield to the
new drive (nice that the big exposed flywheel is gone on
the 2.88), and put on the rails. Because of the black
dust shutter, you can't just slap on those rails.
Instead, start the rear screw first. Now pull out on the
front end of the white rail and start the front screw.
Now you can snug it down with little trouble.
Longer 2.88MB Eject Button
The 2.88 has a little longer eject button
that will prevent you from closing the floppy carrier
back into the case when you have a floppy in it. BUT
since you now have a dust cover on your floppy, you
might be able to live with it. If it really bothers you,
file it down (how crude).
Hacking Refdisk for 2.88MB Support
Don't try this! Do not try to cook up a hacked
refdisk using refdisks of other systems that use similar components! I did just
that and I almost trashed one of my (very few) P75s!
The problem is when you hose the POS values with the bogus refdisk, the
stock refdisk won't work! Worse, it comes up as a Non-System disk. Tim Clarke
is of the opinion that the later refdisks move the extended CMOS area, and
that's what sends the floppy to Nirvana.
Undorking a P75
I was unable to reset the CMOS
with any utility that I tried, the floppy could read the
floppy, but trying to open files produced Disk not Ready
errors.
I noticed that I could boot with a PC DOS 7
boot disk, so out of hope (desperation?) I created a PC
DOS 7 bootable floppy, then dumped all the other files
(minus command.com, ibmbio.com and ibmdos.com) to the boot
disk. I then used Bob Eager's REFSTAMP on it.
The hybrid refdisk will boot to the PC DOS
prompt. I then ran SC.EXE from the command line,
configured, then saved it. Sort of nice with the bootable
floppy, as soon as you hit F3 to exit, it returns you to
the command line. Run SETCLOCK.EXE to set your clock.
Shorting the MC146818AF RTC
Getting to it is half the fun. Undo the
4-40 posts from the ports, then undo the two screws
holding the left end of the MCA slot bracket, unplug the
header from the planar, unscrew the screw at the top
where the braided ground comes in from the plasma
display, unscrew the screw at the bottom next to the
SCSI ID header artifact, then remove the single screw
that is in the center of the "T". Now rock the riser out
of the planar. Wasn't that simple?
With power off and the battery unplugged,
short pins 12 and 24 together for 15 seconds. That's the
certain way to clear it, yet I am not totally convinced
it clears everything.
Pin 1 on the RTC faces left, so 12 is the
rightmost pin on the bottom, and pin 24 is the leftmost
pin on the top. (Thanks to William Walsh for sending a
snippet from the newsgroups).
Stick the MCA slot bracket back on, replace all screws and posts.
Boot with the PC DOS 7/refdisk hybrid. Run SC.EXE and
SETCLOCK.EXE, now the system should (maybe, possibly)
respond.
External Storage Device Connector
Shared with the P70, look HERE
Floppy
Drive Removal
From Jim Shorney (I'm an engineer, not a
doctor)
OK, this is not rocket science, especially
if you have an H1 floppy.

Reach in behind the display panel with your left hand.
Slide your index finger in behind the floppy housing on
the left side about 3/4 of the way up. Then
slide your finger downward along the edge of the housing
until it stops on the catch. At this point, hook
your finger behind the left side of the housing and pull
the side of the housing to the left, maybe 1/4" or
so. Once the little post on the floppy cover
clears the catch, the floppy will flop forward.

Continue to rotate it until it is level, then pull it straight out.
Removing Floppy from Drive Carrier, H1 Model

Unscrew both screws from the upper side of the
carrier. Pull the floppy rearward until the white
plastic piece on the right side is just to the front of
the catch.
Now pull the side of the carrier away from
the drive and pull the drive up on the right side and
pivoting it on the left side. Note:
The floppy will NOT slide out of the carrier.
Reassembling Floppy into Drive
Carrier
This had me stopped for a little bit. You
have both white plastic pieces that screw onto the front
sides of the floppy. Which goes on which side?
If you look into the recess that the drive
carrier fits into, you will notice a black catch in the
upper right corner. Now look at the two white plastic
pieces. Notice that one has a little "arm" sticking up?
This part gets screwed on the floppy on the same side as
the eject button.
Slip the left side of the floppy into the drive
carrier. Pull the right side of the carrier out so the
floppy "rail" will clear. Slide drive forward until it
stops. Install both self tapping screws.
Warning!
There is a aluminum ground shield across the bottom of
the floppy drive. It is attached with four screws
through the bottom mounting holes (which are not used by
the plastic "rails"). It is coated on one side with a
plastic non-conductive coating. To properly attach this
shield, the grounding strap "tab"
MUST be on the same side
as the motor! A simple test- use an ohmmeter on the
shield, one side conducts, the other, not.
P75 SCSI
To me, it resembles the newer SCSI /A with
the 20MHz/12.5MHz oscillators.
P75 SCSI
Tribble (new)
80C32-1 MCU
N8032AH
AIC-6250EL
AIC-6250EL
33F6910
33F6910
33F6715
33F6715
4464S-08LL
SRM2264LM12
20000 xtal KHz?
20 MHz
12500 xtal KHz? 12.5
MHz
OKI 15F7917
OKI 15F7917
Take a look at David Beem's SCSI microcode
levels. The latest ucode for the Tribble is 41G9974 14h/20d date 1992.
Atmel
AT27C256R-15R 28 pin SOIC [package 28R] BIOS and
firmware
Package Type R - 28 Lead, 0.330" Wide, Plastic Gull
Wing Small Outline (SOIC)
SCSI BIOS PN 79F3214 (even) / PN 79F3213 (odd). SCSI
microcode PN 79F3212
Ed. I had Bruce from Blue
Feather Technologies burn me some of the 92F2244
and 92F2245 SCSI BIOS in the small SOIC chips and use
them in my P75s. Up to six SCSI devices can be attached
to the SCSI controller. It supports drives up to
1.05GB.
Terminators
It uses three 8 pin, seven resistor SIPPs, 145
ohm (150 ohm will work fine). Radio Schlock has the 150
ohm #900-8143. Pin 1 is towards the SIMM sockets.
Removing
SCSI BIOS Chips
I want to open my P75 and pull the SCSI BIOS chips.
Might have to figure out some way to remove them (Dremel
off the carrier, then the leads?).
Dr. Jim says:
That's my boy, never use tweezers when a
sledgehammer will do. Removing the SCSI BIOS chips
is trivial. The carrier is a two-piece
affair. Slide the _inner part away from the SIMM
socket (you will notice a small gap at that end of the
carrier). It will make a disturbing 'snap' sound,
after which you can lift the inner portion out.
The chip will lift right out into your grubby little
paws at this point. [Ed.
the neat-o SOIC socket is a Hirose DL3A-26]
SCSI and System BIOS Wondering
Peter wrote:
Today I did a bit experimenting with the
8573-401 P75 portable. I wanted to know if and how
drives over 1GB could be used in that machine.
At first I tried using a 2.1GB Quantum Fireball
attached to the onboard SCSI controller. The drive was
properly recognized with 2.112MB in the setup - but it
did not show up with the proper capacity in FDISK. I
tried Win95 FDISK - which showed a size of 1.024MB
(1.0GB) as estimated even with the advanced large media
support turned on.
Then I installed the short IBM PS/2 Fast
SCSI-2 Adapter /A (60E9) in the second lower 16-bit
slot. The first slot contained a short 16/4 Token Ring
adapter already. While the card has no front tab it just
fits between the rear slotcover and the power supply fan
without squeezing :-) A very tight fit if you ask me.
The internal SCSI cable could be detached from the
planar SCSI port and attached to the SCSI-2 card. The
length is sufficient.
Now: this seems to work.
It is however not possible to configure
the SCSI device(s) attached to that controller, if you
only copy the ADF to the reference disk. Most likely you
will have to use "copy an Option Disk" and get the
updated SCSI.DGS, SCSIHF.DGS and -probably- SC.EXE to
the P75 reference disk. I did not do that ... so
far. Maybe later, because I only have a US-P75 reference
and only a german "SCSI-2 Option Disk" - and if there is
one thing how to voluntarily step in the mud then it is
mixing different language versions.
The P75 also lacks the ability to select the startup
sequence - but at least it had no problem determining
that the planar SCSI only has an external CD-ROM
attached and that the 2.1GB harddisk is on the SCSI-2.
FDISK got straight through and installed a 2GB primary
partition. After reboot the FORMAT C: says "Formatting
2.012,03MB" ... which takes a while, because this
particular drive has some bad sectors, which are not
hidden. Strange. But okay.
Physically the slimline Quantum drive fits
into the half-height HD-cage. But the ID-select cable
has an "old raster" plug for the large jumper pins,
while the Quantum has the "mini jumpers", which are
thinner and have only 1.5mm pitch. Doesn't matter much,
because once set there is no reason to have the drive ID
switched to anything else than the pre-set ID 6
(traditionally I took ID-6 of course).
Sadly the P75 has a soldered firmware ROM
on the processor card. There is no chance to read out
the ROM content *after* the system powered up - and then
the ROM is relocated to an area above 16MB and masked
from access. Only the shadow-copy remains at the
addresses E000 - FFFF and is mixed with the additional
codes from the XGA and planar SCSI.
This is the same method as used on all
PS/2 with 486-class processors (and even 386 CPUs) - but
these have removable ROMs that could be read and
analyzed before the POST relocates the "pure ROM code"
out and only the "compatibility part" remains. I would
really like to compare e.g. a Type 2 (old) and 41G9361
Type 2 (new) code for the advanced SCSI support and try
to add this to the P75 firmware ROM, which *seem* rather
close to the Type 2. Technically the P75 is a sort of
Mod. 77 / Mod. 90 mix in a portable case. It has a
similar memory subsystem (single modules, unpaired) and
the planar SCSI from the "Bermuda" 77, it got the planar
XGA-1 from the Mod. 90. So either of these machines -to
my opinion- could be used to filter out the additional
code that enables the planar SCSI controller to handle
drives over 1GB.
On the Mod. 90 the code can be supplied with the
upgrade version of the the processor board firmware ROM
- why not on the P75 ?
Anyone any idea to this ? I don't have
the equipment to unsolder the SMD-ROM undamaged or read
it out. My EPROMmer takes only DIL-chips ... but that is
the least problem, because I can build / buy an adapter.
The ROM itself is a 27C1001 / 27C010-version (128K x 8
bit) as far as I remember ... I have PLCC 28C010
Flash-ROMs around here ... :-)
Hey Jim - wouldn't that be another
challenge to push out the P75 performance a bit more ?
The advanced SCSI support on the Mod. 77 "B" helps it to
even run 8GB drives .... tried that with my old
Ultimedia 77 and a Seagate Elite-9 drive, before they
were installed in the 9585. No problems getting them to
work under NT 4.0.
Set SCSI ID
|
ID# |
1 |
2 |
3 |
ID6 |
Off |
On |
On |
ID5 |
On |
Off |
On |
ID4 |
Off |
Off |
On |
ID3 |
On |
On |
Off |
ID2 |
Off |
On |
Off |
ID1 |
On |
Off |
Off |
ID0 |
Off |
Off |
Off |
|
SCSI Cable
Note: Both
SCSI connectors have the pin holes facing UP. The length
of the flat and loose is immaterial, but the OAL should
be AT LEAST 6.5". The end for the drive should use a
strain relief.
P75 Drive Carrier
My vision: Get a angle bracket, cut to length, drill
mounting holes in the top and sides.

P75 HD Rail
Dimensions

Dimensions are relative to the end AWAY from the SCSI
connector. The material is 1/2" aluminum angle from Ace
Hardware, cut to 4.5" long. I "flattened" the angle
bracket to show the relations between the holes. Holes
are 5/32".
First hole for the rail to HD cage is .625". second hole
is 3.245". Both holes are .250" from the angle.
Note: The
distance to the angle for these holes is not critical, as
long as you have clearance
for the screw heads.
First hole for the HD to rail is 2.375". second hole is at
4.125". Both holes are .125" from the angle
Note:
These holes MUST be .125" away from the angle, since the
Hard Drive width can't change...
Note: The rails are
mirror images, they are NOT identical!. The dimensions
are the same, but swapped.
Completed
HD Mounting Rails

I finally took matters into my own hands...
Took 4.5" lengths of 1/2" aluminum angle and drilled some
5/32" holes. Note the mounting hole for the left end
(farthest from the SCSI connector) is the same distance as
the old 0661 HD. Oddly, the spacing between that hole and
the first screw for the new(er) HD is 1.75", and the
second HD mounting hole is 1.75" past that... Odd...
The HD mounting holes are .125" from the edge
of the angle, and interfere with installing the screw, so
I used a keyway cutter to mill away a slot to give the
screw head clearance. The holes to mount the rails are
5/32 for now, but I'm thinking of switching to a mild
steel angle because the extruded aluminum is soft. I could
have tapped it for 10/32, but I'm afraid that it
would be too easy to strip the threads from aluminum.
P75 HD Cage
with Drive Rails
Here's a shot with the drive on the rails. I
used 3/8ths inch 8x32 nylon machine screws and nuts from
Ace Hardware. The nylon screws were a close fit in the
5/32" holes, almost like a barbed fastener... You might
just stick with 5/32 and nylon screws for a quick
assembly. Note: The
aluminum angle used may make "shavings" when threaded for
use with steel screws. Consider threading for 8x32 and use
nylon screws...I wonder if a thread forming tap
would work.
Using aluminum is OK, but be careful of threading.. Use
the same diameter drill for all holes if you can. Use a
1/2" diameter by 3/16" wide keyway cutter. A .750" dia
cutter leaves too much flash.
If you use an ER-20 collet chuck, get a 3/8" shaft keyway
cutter so it fits...
Brightness
Program
To install Brightness program, run Brtinst.com from
the refdisk. This installs brt.com.
To have emphasized text brighter than
standard text, type "BRT" and press Enter. To have
standard text brighter than emphasized text, type "BRT /H"
and press Enter.
The P75 has XGA-1 with 1MB VRAM.
The internal display however supports only the 640 x
480 mode and turns off if any of the higher modes is
used. This will explain why you can get a picture on the
external screen but not on the plasma.
You will have to stay at the low-res mode here, since
the display is from the principle only a "generic VGA
screen" (same as on the P70 BTW).
P75.EXE
While the system is running, this utility allows
you to switch from the IBM external display attached to
the XGA2 Adapter and the plasma display or the IBM
external display attached to the XGA external
port. To do this, just type P75 at a dos prompt
and the XGA2 Adapter with the monitor connected will be
disabled and video will output to the plasma display or
the display hooked to the XGA port.
Type "P75/u" at dos prompt (undo) option to return to
the monitor connected to the XGA2 Adapter.
Active
Matrix LED Screen Prototype
Original article HERE
"IBM Rolls Out 22-Pound, 486 'Luggable'
PC"
By Ed Scannell InfoWorld Nov 19,
1990 Pages 1 and 141
As part of the announcement, the company last week demonstrated a flat-panel
color display it jointly developed with Toshiba. However, IBM officials
declined to say if it would be available for the P75. The color display is
scheduled to be delivered in the first half of 1991, IBM officials said.
Reversing Course:
IBM’s Strategic Recovery in the Flat Panel Display Industry
The big move came in 1986 when IBM entered into a two-year joint research
alliance with Japanese manufacturer Toshiba focused explicitly on full-color,
active matrix (AM) LCD TFTs. IBM initially considered other partners such as
GE, Sharp, Matsushita, and Hitachi but settled on Toshiba in part because
“they were probably hungrier than others” and in part because, at that
point, Toshiba had built the largest prototype.
The relationship initially focused on proving that the smaller (2”-3”)
LCD televisions could be effectively scaled up to larger sizes, and then moved
to the creation of a 14” full color prototype computer display. In 1988 the
two firms signed a joint venture agreement to create Display Technologies Inc.
(DTI) and build a manufacturing facility in Himeji City in Japan next to an
existing Toshiba monochrome LCD plant. By 1991, DTI had created the monitor for
the P75 portable and in 1992 for the first IBM ThinkPad. In 1992, DTI produced
around 500,000 TFT panels for use by IBM and Toshiba, as well as for sale to
other companies.
Riser Swap with P70
Ever thought of using a P75 riser on a P70? Well, it won't work. The riser
may physically fit, but the P75 has a 14-pin header from the planar to the
riser card. Of course, the P70 lacks it entirely. Probably the extra control
lines?
Win98SE on
P75
Peter says:
Today I have tested my trusty old
"PortaPotty" 8573-401 (P75 Luggable) with Win98SE. My
configuration: unmodified 486DX-33, 8MB (2 x 4) on the
planar, 32MB (4 x 8) on the Acculogic Simmply RAM, Madge
16/4 TR (TROPIC chipset), Maxtor MXT540S at SCSI-ID6,
external CD-ROM II (caddy loaded) in 3510-AV0 enclosure.
Win98SE install took about 3 hours ... I went
away in between for lunch and missed to "press any key".
The system hung at one point prior to the first reboot
after the files had been copied from the CD and before you
are asked to enter the 4 x 5 ident characters. I switched
the machine off and powered it back on. Caused no major
problem except waiting for the 40 Megs RAM to count up.
Result (after that long time): "Your system
is optimal configured". No 16-bit mode, full access to the
CD-ROM etc. pp. ... but it is rather slow. Guess I'll have
to send in the processor board to Doctor Jim for some
supercharging ... :-)
P75
System ADF 0E0FFh AdapterName "Built In
Features"
Serial Port
Serial 1 through Serial 8, or disabled.
<SERIAL_1
03f8-03ff int 4>, 2 (02f8-02ff int 3), 3
(3220-3227 int 3), 4 (3228-322f int 3), 5 (4220-4227 int
3), 6 (4228-422f int 3), 7 (5220-5227 int 3), 5 (228
-522f int 3), Disabled
Parallel Port
Parallel 1 through
Parallel 4 or disabled.
<PARALLEL_1
03bc-03bf 1278-127f int 7>, PARALLEL_2
0378-037f int 7, PARALLEL_3 0278-027f int 7, PARALLEL_4
1378-137f int 7, Disabled
Parallel Port Arbitration
Level
Arbitration levels 0 through 7.
<Disabled> places parallel port in compatibility
mode.
<Level 6>,
5, 4, 3, 1, 0, Disabled, Level 7
Preempt Enable/Disable
System board CPU can preempt continuous
data transfers by other devices on the MCA bus.
<Enable>,
Disable
Video I/O Address
I/O address range for Display Controller
Registers and location of video coprocessor
registers.
<Instance
6: 2160h - 216Fh>, Instance 1: 2110h -
211Fh, Instance 2: 2120h - 212Fh, Instance 3: 2130h -
213Fh, Instance 4: 2140h - 214Fh, Instance 5: 2150h -
215Fh
Video ROM Address Space
Memory address range used by system
video ROM.
<C0000
- C1FFF>, C200-C3FF, C400-C5FF, C600-C7FF,
C800-C9FF, CA00-CBFF, CC00-CDFF, CE00-CFFF, D000-D1FF,
D200-D3FF, D400-D5FF, D600-D7FF, D800-D9FF, DA00-DBFF,
DC0-DDFF, DE00-DFFF
Video Arbitration Level
The video
sub-system can use any available arbitration from level
8 through 14.
<Arbitration
level 13>, 12, 11, 10, 9, 8, 14
Video Fairness
Whether or
not video sub-system coprocessor follows the fairness
algorithm for bus usage.
<Fairness
On>, Fairness Off
Auto-Dim Time
Auto-Dim
function automatically turns plasma display off after
specified period if no input from the keyboard or
auxiliary device is received. Auto-Dim Time can be from
1 to 120 minutes.
<10
Minutes>, 20 Minutes, 30 Minutes, 60
Minutes, 120 Minutes, 1 Minute,5 Minutes
Auto-Dim Reset
There are two ways to turn on the display
again:
1. Pressing SHIFT
2. Clicking the mouse.
If the mouse
picks up vibration on a desk which turns on the display
again, change Auto-Dim Reset from <Keyboard and Aux.
Device> to <Keyboard Only>.
<Keyboard and Aux. Device>,
Keyboard Only
Color to Gray Mapping
Some applications that are
developed for color displays can be used on monochrome
displays. For such applications, reset Color-to-Gray
Mapping to <Green Signal Only>. Setting <RGB
Mixed Signals> may result in an unpredictable display
image.
<RGB Mixed Signals>,
Green Signal Only
Turned-on Display
Primary turns
on only one display that is considered to be the primary
display.
No external display -
Plasma is primary display. Only VGA is supported.
External display - External is
primary display. VGA or XGA supported on external port
Plasma and External
turns on both plasma and external display. Only VGA mode
is supported.
<Primary>,
Plasma and External
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