8595 / 9590
  The 8590 and 9590 uses the same reference and diagnostics disks used by the 8595 / 9595 systems. for a list by processor complex, go HERE

SHS15F2247.boo     IBM PS/2 Model 90 XP 486 HMS  (Requires IBM Bookreader)
SHS15F2249.boo     IBM PS/2 Model 90 XP 486 HMR  (Requires IBM Bookreader)

Model 90 HMM Extract  Model 90 information from HMM 

190-176 IBM Personal System/2 Model 90 XP 486 (8590-0J5, -0J9 AND -0KD)
191-057 IBM Personal System/2 Model 90 XP 486 (8590-0G5 AND 0G9)
191-195 IBM Personal System/2 Model 90 XP 486 (8590-0H5 and 0H9)
192-098 IBM Personal System/2 Model 90 XP 486 (8590-0L9 AND 0LF)
193-082 IBM Personal System/2 Model 90 XP 486 (9590-0LA AND 0LF)

US5136465A PC with tandem air flow dual fans and baffle directed air cooling (Model 90)
US5191544A PC enclosure with shielding (Model 90 Drive Bay EMC Bezels)
US5353202A PC with shielding of input/output signals (Model 90 Planar Port shielding)
US5162979A PC processor card interconnect system(Model 90/95 Complex)
US5008829A PC power supply (Model 90 PSU)
US5420760A Microcomputer enclosure with interrupted wedge locking arrangement and shielding liner (Model 90 Case)
US5980275A Electronic circuit board interface (mezzanine) mounting bracket (card bracket)

Running W98SE with >64MB, only see 65MB? Use W95 HIMEMUPD 
SPOCK206 Windows 95/98 IBM SCSI Miniport Driver
SPOCK206 for Windows NT IBM SCSI Miniport Driver
XGA208 Windows 95/98 XGA-2 Display Driver by UZnal
XGA208 WinNT 4 XGA-2 Display Driver by UZnal (limited to 256 colors)

Model 90 Power

Model 90 Front View
Model 90 Planar  
   KB / Mouse Port Filter  
   Base Fan (fan in front of complex)
   Why was Model 90 Introduced?
   DBA-ESDI Boot Support with the Type 0
   "Model" 90 Careful cable routing and component selection
   "Clean" CDROM Attachment
   J1 on 90 Planar
   DBA Artifact on 8590s (Yes, they DO work!)

Type 0 and DBA-ESDI Success!

Model 90 Ports
Mounting Model 90 Vertically
64K Colors Supported under W98SE
   Video Ram
     Video RAM Installation
   8590 and 9590 Planar Differences
   9590 Floppy Controller
      Model 90 Floppy Cable 
      Adapting 34 Pin Clone Cable to 40 Pin Port
    Floppy Sleds
      Three Floppy Experience
      * Marked 2.88MB Floppy Drives on 8590s

Hard Drive Slides
   Model 90 Drive Slide Conductive Coating
   Memory Riser
     Orienting SIMMs on Riser
      Loading SIMMs   
      8590 Memory Parity Errors / Configuration H095511
         ECA084 Model 90 Memory Riser Card
      Error 201
      Plastic SIMM Holders
      Riser Support Bracket
   Memory Expansion Boards
 
Planar ADF Sections (PFF6F.ADF)



8590 / 9590 Planar

 
BT1 Battery   CR2032
J1, 3, 6 Adapter slot
J2 Power switch/speaker
J4 AVE slot 
J5 Fan connector 
J7 Processor-board slot 
J9 Video 
J10 Power-on password
J11, J14 Memory-riser slot 
J12 DB25 Serial  Built In Features
J15 40 pin Floppy port
J16, J23 DBA ESDI sockets
J17 DB9 Serial Planar Device 6 Serial Port # 2  
J18 Parallel Port
J19 Mouse Port
J24 Keyboard Port
J25, J26 Power-supply 
Y1 32.768KHz 
U1 LM386 Audio Op Amp
U2 74F30 8-Input NAND Gate
U7 DS1210 Nonvolatile Controller Chip
U9 41.5390 MHz  Used on XGA  
U13 14.3181 MHz "System Oscillator".
U14 37F0842 Used on XGA  
U16, 19, 20 TDK ZJY-2P Used on XGA  
U18 25.175 MHz Used on XGA  
U21 44.9000 MHz Used on XGA  
U22 28.3220 MHz Used on XGA 
U23 Dallas DS1285 RTC
U24 SRM2264LC-12
U25-U29 Video Memory
U36, 38, 40 Video Memory
U64 Toshiba TC110GC9AF (74F5160) 
U65 40.0000MHz  DMA Clock
U67 85F0464 (95 M planar)  
U72 TI CF61533FN (64F3110) 
U77 22.1184 MHz Clock
U84 N82077AA Floppy Controller 
U87, 88 64F0942 (95 M planar)
          -  OR  -
U87, 88 33F5469 (7568 Resource Card)
U92 24.0000 MHz 

U77
22.1184 MHz Clock for "Type 3 High-Speed UART".
              Divided by 2 for better waveform and 1:1 ratio of low and high.
U64 XGA Display Controller Early TC110GC9AG / 1888676 Late TC110GC9AF / 74F5160
VRAM Toshiba TC524256BZ-10 / NEC D42274V-10 / OKI MSM514262
TDK ZJY-2P 2 Line Common Mode Choke datasheet 
U14 37F0842 equivalent to INMOS G190 Serializer Palette DAC
U64 TC110GC9AF equivalent to INMOS G200 XGA Display Controller
U31 - 32K sprite memory, between U64 and J14. SRM20256LM12 or CXK58257AM-12L

Model 90 Serial Ports  
J12 DB-25 Serial Port  "Built In Features" --> "Serial Port" 
J17 DB-9 Serial Port   "Planar Device 6 – Serial Port No. 2" 

KB / Mouse Port Filter  

While consoling Tomแš Slavotํnek over his lack of a Model 90, he sendt me a picture of a sweet early production Model 90 from an auction. Not even dust inside....



And what do I see but an EMI filter next to the KB / Mouse port. My guess is the IBM engineers started with the Model 70 systemboard, where the EMI filters WERE required. But the engineers did a better job with the Model 90 planar design, -OR- putting a bunch of signal dense components on the complex removed significant noise...

We will most likely never know, the engineering notes were hidden [oh, the humanity!].


J5 - Base Fan
Two access holes through the Model 90 Base Frame to allow for the removal of the Base Fan 64F4128 WITHOUT having to remove the Adapter Card-Guide Assembly 33F8363.

Just noticed something, the speaker is only about 3/16hs in front of the fan opening... wonder if you couldn't pull it from it's white frame and SIMMply put it down on the bottom of the frame. Bet the magnet will hold it in place...

Another item, the fan is darned near impossible to touch, as it is behind the grille in the frame -AND- it is mounted to the card guide. So why IBM felt it needed a front and rear finger guard, I dinna ken. BUT the wire used to form it is 1/16ths diameter, so if you wandt to drop both the front and rear finger guards, the mounting screws won't go into the card guide deep enough... Might be a 3/16th or so nylon spacer on each mounting screw would allow you to drop the finger guards and run the base fan without them...

Panaflo DC Brushless
0128A0-Z
Model FBK-08A12L
DC12V 0.09A
Matsushita Electric Japan

  size    Power  Air flow  Air pressure   Noise      Model
 -------  -----  --------  ------------  -------   ----------
 80x25mm  0.66W  22.6 CFM   1.8 mmH2O    23 dB-A   FBK-08A12L

FBK-08A12L
Motor Type FB: Panaflo (DC Axial-flow fan)
Bearing Type K: Ball Bearing
Housing Size 08: 80 x 80mm
Housing Thickness A: 25.5mm
Rated Voltage 12: 12 VDC
Speed L: Low - Maybe 1900 RPM
Solid Corners

Base Fan Connector 
KK 3.96mm Crimp Terminal Housing, Friction Ramp, 2 Circuits
https://www.molex.com/webdocs/datasheets/pdf/en-us/0009508023_CRIMP_HOUSINGS.pdf

Base fan uses AWM Style 1007, 24 AWG wire.

Use With KK 3.96 Crimp Terminals, 2478 , 2578 , 6838, 7258 , 45570

Model 90 Power Switch Positions
 

Push In, Button stays recessed - On
Push Again, Button extended - Off

Power Switch  Schadow 221
https://web.archive.org/web/20070331050147/http://ittcannon.com:80/media/pdf/catalogs/Leaf/SW_push_f.pdf

F2UEE is closest.

Remove Cover 

IBM says:
Loosen both thumbscrews on back panel.
Remove cover by sliding it forward approximately 50 mm (2 in.), and then lifting it.
Reverse procedure to replace cover.

My way (or the highway)

Loosen both thumbscrews on back panel. Do NOT remove them, they are captive.

Remove cover by slapping it on the sides with the palms and fingers of both hands, thumbs on the top of the case. Slide it forward @ 2 in., and then lifting it. Sometimes it takes more moxie to start the cover.

Reverse procedure to replace cover by SIMMply placing the horizontal pins into the rails, then slowly push the top cover rearward until it seats..


Audio Over MCA


Why was the 90 introduced?
Dennis Smith 
   The Model 90 was intended to be a "desktop server".  It came out in 1989/90.  A few years before the Bermuda 77 and Lacuna 77.  The 77 was the replacement for the Mod. 90, but it continued in the 95xx Premium Line until about 1994. The main reason for releasing the Mod. 90 was most likely to replace the Mod. 70 and to have a desktop cousin to the Mod. 95.

DBA-ESDI Boot Support with the Type 0: Daniel Hamilton dug down into the Type-0 abyss and found out while yes you can boot from the DBA-ESDI drive, you must still have a SCSI drive on a Spock to provide IML. Read his further bone-chilling adventures in the DBA-ESDI Temple of Doom HERE  Being able to boot from a DBA-ESDI drive as C: offers a simple upgrade path for the Model 70 to Model 90, just by swapping the drive out.

Martin Adams 
   One advantage the model 90 has over the 77 is the 8 SIMM slots. Eight 8MB SIMMs are allot cheaper than four 16MB sticks right now. We also have the caching SCSI that could have its cache upgraded. You don't have to pull adapter cards to reconfigure RAM. I prefer the planar mounted bus connectors too. 

From Us, the god-Emperor of Micro Channel:
  After many years of dabbling in Processor Complexi, I find the Model 90 (8590 or 9590) to be THE preferred complex based system to experiment with complexi and / or memory. The 95 is still my heartbeat, but consider:

Complex Seating - The Model 90 orients the complex vertically, so you can press down on the center top edge of a complex to seat it. The 95 forces you to drop it down on it's side if you want to firmly seat the complex, or try to hold the complex with one hand, center the complex in the double long socket, and press it in while bracing the system with your other hand.

NOTE: From sad personal experience, on a 95 standing up, the complex can hang down below the complex double slot if you don't pull the blue levers stick straight up from the planar before trying to seat the complex. Then carefully place the complex edge connector in the complex slot.  Push the complex in until it seats and the fingers on the blue latches are lined up with the case supports. You may have to push one end of the complex in and then the other.

If you cheat and use the blue levers alone to seat it in a Model 95 without firmly seating the edge connector in the slot, you CAN shear off some surface mount components from the lower back side.

Changing Memory - The Model 90's memory is on removable cards, to change memory, you pop the cover off, remove the riser bracket, and pull the risers. On the Model 95, you have to pop the front bezel, pull off the side wall, pull the AC plug out of the back, loosen the PSU, drop the PSU, change the memory, then push any cables out of the way before putting things back together...

Where the 95 edges out the 90 is drive bays and better work area. The 90 has a peculiar floppy cable, and when you add a ribbon SCSI cable, things tend to get jumbled between the corner of the drive support shelf and the PSU support bracket. Using a flexible sheathed cable like in the 957x series or the 95's F/W cables, it becomes much easier. I would like to see a round single floppy cable for the 90. That would really help eliminate the cable confusion.... Actually, the 95 could benefit from a round single floppy cable as well. I usually stuff the unneeded floppy connectors in the B: area. But that makes seating a full length card in Slot 3 a struggle.

Mounting a CD ROM in a 90 depends on having the correct width drive sled and finding the uncommon CD Rom bezel.

Whatever. If you think of it, a 90 is a fun box for the experienced user.

Model 90 Mockup (?)


This is an image snagged from UMMR, from an ad for a complex update for the 90 / 95. Of particular note is the Bay D bezel in the lower right. Might make a decent cover for a SCSI2SD adapter....

"Model" 90
  A Model 90 is a system for a more experienced individual. Not that it is any more difficult than a 95 to configure, but you have to accept it has four slots and XGA on the planar. Thanks to UZnal, we now have True Color support for the XGA under Win9x AND protected mode support for the IBM SCSI adapters running on Pentium systems.



Look at this ode to simplicity! The 50 pin flat cable is gone, making servicing the RAM risers _SO_ very much simpler. Do you see how the cable runs to the front, then under the adapters? Using a SCSI cable that is long enough is crucial here, as short cables force one to place the SCSI card closer to the complex, and forcing you to run the cable over the complex or under the complex and barely reach the drives.

NOTE: I always wondered why the P60 and P66 complexi heatsinks were milled in that odd step fashion. Look how it clears the adapter card bracket...

CDROM Attachment


Look at the cramped space available for hooking up the CDROM. What is difficult to see here is the thoughtful SCSI cabling. The F/W cable goes up to a 68 to 50 pin adapter.

Now the space saver is the short length of 50 pin flat SCSI cable (white socket) running from the 68 to 50 pin adapter to end in the SCSI CDROM. The F/W cable then ends with an active terminator.



Trying to insert a 68 to 50 pin adapter in the CDROM, then plug in a F/W HPDB68 plug into that crams the SCSI cable up against the front of the PSU.

Fast/Wide to 50 Pin SCSI   Wide to Narrow Adapters DM5000-5068-02 
I was in deep Super High Intensity Tinkering with a Model 90. Trying to hook up a 50 pin SCSI device to a F/W cable, and as many of you have experienced, there ain't much room, especially if you are trying to have a 50 pin stub cable....

What would make life easier is a Wide to Narrow adapter, Female to Female. These plug INSIDE the 50 pin MALE connector on the SCSI device and the wide 68 pin MALE plug on the F/W cable fits OVER the FEMALE wide plug. Remember to have a wide device [SCSI drive -OR- active terminator] AFTER the narrow device to terminate the SCSI bus.

NOTE: I personally wandt a real wide terminator device after the narrow device.

Methode made the Datamate line of SCSI cable adapters, and one appears to be what the doctor ordered and why the preacher danced.

DM5000-5068-02 = Universal Feed Thru with Capacitors on High Lines

Optional capacitors (10pf) are used in adapters on the additional 9 high signal lines when going from a wide controller to a narrow device to balance the loading to all signal lines.
Does not terminate, so you need a device that can terminate at the end of the F/W cable [either a SCSI drive or an active terminator].

NOTE: Be careful, some DM adapters are for differential!

Alternative - No Internal CDROM  


I attained a higher understanding of the blue mysteries when I decided to run an external CDROM. Take the SCSI HD out of C Bay and SIMMply stick it in B bay. Enable termination so it can be the last device on the SCSI bus.

The only clutter is the original floppy cable. I'll still use the original cable while grabbing some round clone floppy cables.

Top Routing of SCSI Cable  


See the SCSI cable on top? Plenty of room under the blue air baffle. I tried sliding the HD into A bay, but the HD slide only goes in about 2/3ds of the way, then STOPS. The floppy slide's mounting holes are spaced differently than the HD slide.

The single device F/W cable is 06H6660.


90 Ports


Mouse and Keyboard Ports HERE
   The new keyboard/mouse controller used on Model 90 and Model 95 XP 486 systems provide additional functions for mouse support. These include the ability to separately receive and send data to the keyboard and mouse ports simultaneously. This is not possible on previous PS/2 systems as only one I/O port is used for both keyboard and mouse data.

Serial Port    (In Accordance With EIA-232-D)

DB9 Serial Port Pinout    [Planar Device 6 – Serial Port No. 2]

DB9 Serial Port Pinout

Pin

Signal

1

Data Carrier Detect

2

Receive Data

3

Transmit Data

4

Data Terminal Ready

5

Signal Ground

6

Data Set Ready

7

Request To Send

8

Clear To Send

9

Ring Indicator



DB25 Serial Port Pinout   [Built In Features - Serial Port]

DB25 Serial Port Pinout

Pin

Signal

Pin

Signal

1

N/C

14

N/C

2

Transmit Data

15

N/C

3

Receive Data

16

N/C

4

Request To Send

17

N/C

5

Clear To Send

18

N/C

6

Data Set Ready

19

N/C

7

Signal Ground

20

Data Terminal Ready

8

Data Carrier Detect

21

N/C

9

N/C

22

Ring Indicator

10

N/C

23

N/C

11

N/C

24

N/C

12

Reserved

25

N/C

13

N/C

0

0


NOTE: Current Loop interface is not supported on either serial port.

    Dual DMA serial ports (Type 3 Serial Controller), one DB25 and one DB9. The DB9 port requires feature number 0217 or 0242 for attaching devices with 25-pin D shell connectors.

    The DMA serial port supports 300 bps to 345.6K bps. DMA reduces CPU loading and overhead at higher speeds. Speeds up to 345.6K bps are supported using IBM Enhanced EIA-232-D which requires a special shielded cable up to 20 feet long.

   Ether serial port can be set to Serial 1-8, with different arbitration levels for Transmit or Receive. Both ports are limited to Int 3 (Serial Controller chapter of HITR says Type 3 Serial Controllers can use Int3 or Int4. YMMV).

DMA Parallel Port
With most Micro$oft products, enabling "Arbitration Level" results in problems, since IBM developed the DMA parallel port prior to industry standards being developed. You may have to disable Arbitration Level if your parallel port device fails to work.

Parallel Port Resources  
PARALLEL 1 (03BC-03BF 1278-127F int 7)
    NOTE: Parallel Port Arbitration Level "Disabled" sets Parallel 1 to Bi Directional mode
PARALLEL 2 (0378-037F int 7) Bi Directional
PARALLEL 3 (0278-027F int 7) Bi Directional
PARALLEL 4 (1378-137F int 7) Bi Directional (or so the Model 90 SSI says)
Disabled (no parallel port at all)

NOTE: The Parallel_1 dual I/O address range of (03BC-03BF 1278-127F int 7) has the Bi-Di compatible port at 03BC-03BF, while enabling dedicated or shared DMA operations enables DMA operations at 1278-127F (Model 90 SSI says 1278-127D... YMMV). The split was due to the old [and obsolete] MDA and Printer adapter I/O range.

NOTE: IBM defines Parallel_2 as 0378-037F int 7, while everybody else calls it LPT1... So if you use a M$ product, and your printer won't print, check to see if both refer to the same I/O range. IBM only supported Int 7 on any PS/2 planar parallel port.

Parallel Port Arbitration Level
   Use any listed arbitration level.  Shared means other devices can use same level, Dedicated means only this device can use that level.  <Disabled> sets port in compatibility mode.
      <"Shared 7">, 6, 5, 4, 3, 1, 0, Dedicated 7, 6, 5, 4, 3, 1, 0, Disabled

NOTE: IBM developed the DMA parallel port prior to industry standards being developed, so most time when you enable DMA, hilarity ensues. If you are using a parallel port connected device and it is misbehaving, Disable the Arbitration Level. Sad but true....

NOTE: It may be possible to use Parallel_2 [LPT1 clone-wise] to enable DMA support. The Parallel_2 I/O range is mostly identical to the clone LPT1 I/O range.

Mounting Model 90 Vertically

    Vertical mounting of the PS/2 Model 9590 requires an appropriate fixture. The Model 90 left side vents point downward, with a minimum of one inch (25.4mm) between the vents and the supporting fixture.


J1 on 90 Planar
Pin
Function
Pin
Function
1
(-) Power LED
5
(+) SPKR
2
(+) HD LED
6
(-) SPKR
3
(-) HD LED
7
(+) PWR
4
(-) PWR 
8
(+) Power LED

J16 and J23 Artifact- IBM brought out a "low-end" Mod. 90 with DBA-ESDI and a 386DX-20 processor board. (Ed. A big insurance company (Aetna?) had 386DX-20 complexes made for it- the "Type 0").

NOTE: Apparently, so did Royal Bank...

64k Colors under W98SE
   W98SE has 640x480x64k at 60Hz support. This requires 8 Video ZIPPs to be installed.

Video Ram
   VRAM chips are Toshiba TC524256BZ-10 or NEC D42274V-10. Model 90 systems have 8 sockets or 4 sockets / 4 soldered VRAM. 

NOTE: Any reference that says the 9590 has XGA-2 on the planar IS WRONG!!! It has 512K soldered on the planar, plus 4 sockets for the 512K video memory upgrade. To make the 9590 ISO compliant they had to install XGA-2 cards in them.

Ed. It is possible (Loch Ness Monster or Big Foot likely...) that IBM did do a few XGA-2 Model 90 planars. Never seen or heard of one. BUT... I have seen a picture of a P75 with an active matrix LCD screen instead of a plasma display. So _MAYBE_ the IBM Canada site referred to a short lived variant... YMMD.

Video RAM Installation



Note the white dots towards the rear of the planar.

Insert VRAM Into Sockets  


   Place insertion tool (1) over empty VRAM socket (If you have one!)
 
   Align beveled corner (2) of VRAM chip towards the dot on the planar. Carefully align the pins with the socket (3) and firmly press the module straight down into place 

   Do not start one end before the other. You can slightly rock the chip side to side to install into a stiff socket, but be careful!

Which Slot for the XGA-2?
   For complexes with search IML BIOS (T1 / T2 with upgrade BIOS, all T3 / T4), the XGA-2 may be installed in Slots 1, 2, and 4. For T1 or T2 with non-IML search BIOS, Slot 1 must be filled with an IBM SCSI adapter, and only Slots 2 and 4 may be used for the XGA-2. Slot 3 is an AVE slot and is physically incompatible. For a full discussion, go HERE

Note: The AVE at the rear of Slot 3 is disabled when XGA is in extended graphics mode.

Differences between 8590 and 9590 Planars
   9590s lack DBA-ESDI artifacts, have 512K VRAM soldered on planar, and is a pretty green. The 9590 planar shows up as an XP 90 system board under setup. The parallel port has DMA support, but no Expressprint and no Wake on Ring. 



9590 Floppy Controller
  82077AA  Go to Floppy page for more. The Model 90 uses the 40 pin floppy header on the planar. The Model 90 Type 2 diskette controller is compatible with the type 1 controller used on previous PS/2 systems. It supports:
• 1.44 MB 3.5" diskette drives
• 2.88 MB 3.5" diskette drives
• Internal tape backup unit
• 1.2 MB 5.25" 1 inch high diskette drive. (supported only by the type 2 controller)

Diskette Drive Cable
The Model 90 supports three diskette drives through the type 2 diskette controller. A cable with three diskette drive connectors (pin format not berg or edge connector) attaches directly to the planar. In an environment with two or three diskette drives installed, the specific
connector that the diskette drive connects to determines its physical drive number. This is important in a selectable boot environment. All connectors support all diskette devices listed above, in any combination. The connector layout is different in the Model 90 and Model 95  systems:

Diskette Drive Signal Cable FRU 57F3030 -or- P/N 33F9953


Adapting Clone Cable to 40 Pin Port
   I picked up some sweet Vantec clone single floppy cables on ebuy. The space that the normal 90 floppy cable, with it's three device cable, is seriously cramped, even without the PSU support strut.This is a way to remove one 34 pin header, alter the cable, then crimp on a 40 pin plug.



PAY ATTENTION!
The keys for both plugs are on the LEFT.
Pin 1 [red wire] HAS to be on the LEFT side.
Both plugs have the holes facing UP.

I don't know what happens if you miswire or swap orientation of the plugs. But you are placing signals where they weren't designed to go. YMMV.

Adapting a 34-pin Cable 
   From the red wire (pin 1), count up 9 wires and slit about 2" from the 40 pin plug. Count up another seven wires, then slit about 2" from the 40 pin plug.

   Pull wires 10-16 (the ones you slit), and twist them 180 degrees [sets this floppy to A:]. Align the lower 9 wires, the twisted 7 wires, and the remaining wires through the 40 pin plug. Crimp. Trim excess with X-Acto knife or similar. Done.

Hard Drive Slides

The original Model 90 HD slide, 64F4863, fits C: and D:... There may be an earlier drive slide, 54592-001, Watson Code C-1961. The 54592 is about the same, except the lifting tab has square edges at the tip, while the 64F4863 lifting tab has a beveled edge at the tip....

61X8724 is the same length from latch to rear of 64F4863 slide, but the sides are about .25" longer to the front. Fits great, the cut-outs in the EMC bezel are not really needed.

64F4863 (Top) and 71G7506 (Bottom)



The 76/77 drive slide, 71G5706 (71F3300 appears to be earlier version) will not fit in C: (too long, plus catch is about .1 too long), BUT... BUT... if you slide the 76/77 slide into the D: bay, you will notice the frame recess is longer AND there are two sets of recesses for the catch at the front. Fits fine.

71G5706 left (D drive), 64F4863 right (C drive)


C drive bay left, D drive bay right


Now why did IBM do THAT? Two sets of drive retainer slots?

Perhaps... the DBA-ESDI drive sled fits the C bay, and IBM wanted you to be able to use the 56/57/76/77 drives in D???

Calculate Hard Drive Mounting Screw Length for Model 90 

If you ever loose your Model 90 Hard Drive mounting screws, here's some facts:

The Model 90 Hard Drive Slide has recessed screw pockets.
Pocket is .315" diameter. Normal #6-32 screw heads are .262" in diameter.
Pocket is .105" deep, higher screw heads will drag against the drive slide guide / base.
Web thickness above the screw head is .135"

Maximum depth of bottom HD mounting screws is 6mm [about .236"] deep into the HD.

So, let's calculate the MAXIMUM screw length for a HD mounting screw in a Model 90.

The screw looses .135 passing through the web of the drive SLIDE. Max depth for a vertical mounting screw INTO the HD is .236, so .135 + .236 is .371 MAXIMUM length.

[ed. 3/8" screws work just fine]

Hard-Disk-Drive Removal Tool 64F4126


US5325264A Device for removing a direct access storage device from a personal computer
This patent is for a plastic tool that pivots on the 90 plastic drive frame, hooks under the "lip" of the DBA-ESDI sled, and lifts the tab up and pulls the edgecard out of the planar socket...

So... that little plastic tool hanging off the inner rear wall of the Model 90 is specifically for a DBA-ESDI drive. They would normally NOT be supplied with a SCSI based system.

How to Remove HD Removal Tool 
The tool has a set of barbed teeth at the top, which fit into "107". There is a hook which slides into "108". Pry the top out from the case and rotate the top of the tool forward, once the top is free, pull up and out.




Side View
Tool Position, Inserted
Tool Position, Drive Freed

Using a 71G5706 in D Bay

I seated a 71G5706. While the catch does not engage, it is a firm grip anyways, the EMC bezel is cut out at the corners AND has a cutout at the center where the longer catch fits snugly.

For those new to PS/2s, such a combination would seem miraculous, but I'd rather chalk it up to a pragmatic decision. If the slide remains the same, then alter the EMC bezel...

Model 90 Drive Slide Conductive Coating

While digging for some AMP F/W connectors and Specta-Strip SCSI cable, I foundt another Model 90 hard drive sled, 64F4863. Again, another sticker saying "ENSHIELD-C". So I wendt looking and sha-zaam!



http://www.applicoat.com/pdfs/emirfielectroplating.pdf

"Electroplating is widely used for depositing a variety of metallic coatings onto plastic and metal substrates. Although most widely used for coating ABS or ABS blends many other plastics can now be coated. These include polypropylene, polysulfane, polyester, polycarbonate and other engineering resins. Electroplated coatings are unique in their ability to combine aesthetic appeal, wear and corrosion resistance with very high levels of shielding."

Floppy Slides

Three Floppy Experience
  Just because people said it isn't done, I threw three 1.44MB floppies into my 9590. All three showed up under setup as 1.44MB drives. Under DOS, they are accessible as A:, B:, and D:. Under W95, it blows the mind of the IOS driver and Win95 says you must shut the system down and restart Windoze. But under safe mode, I was able to access and read off the D: floppy. 

* Marked Floppy Drives on 8590s
   Older 8590s may have their floppy controllers FRIED if you use a 2.88MB floppy that has an asterisk ( * ) on the upper surface of the eject button. The 9590 is not affected by this charming quirk. There has to be an earlier floppy controller other than the 82077AA, which supports an asterisk marked floppy on my 9590. 


Memory Riser

Orienting SIMMs
   When inserting SIMMs onto the riser, orient the notch on the SIMM with the notch on the riser. Always wondered why the riser had that seemingly useless extension to the right. Think of the riser as a big SIMM with it's notch. Like to like... 

Plastic SIMM Holder Clips
There also was a problem with local power-drops on the early Mod. 90 memory riser cards (the ones with all-plastic SIMM-sockets). Improved versions had metal holder clips. And - logically - you should not mix the two versions. 

Memory Riser Card Support Bracket
There *must* be a plastic Support Bracket clipped over the 2 (two !) memory riser boards to properly fix them. This part is called "memory riser card support bracket" and is FRU 57F3029 [black] or 64F5752 [white]. It also has a "bay" to guide the SCSI-cable surface wave filter (that large heavy ferro-oxide block). 

Further Super High Intensity Tinkering with the Memory Riser Bracket show it does two basic functions first, retain the memory risers in the planar sockets, second, provide a space for the SCSI EMI filter.

The retaining function covers keeping the risers down in the sockets via the bracket's fit against the underside of the cover. The other part is keeping the top of the risers from rocking back and forth between the complex and PSU.

Ferrite Filter on Memory Riser Bracket 


Memory Riser Position 


White Memory Riser Bracket  64F5752

Jelte shows us there's still some variations in the Flux Capacitor...



Loading SIMMs Onto Memory Risers

   Memory must be loaded in matched pairs (size and speed) into sockets J1+J3 and J2+J4 for interleaved configurations. (Type 1, 3, and 4 complexes). Type 2 complexes allow you to stuff SIMMs in the sockets in any order or combination, but if not in matched pairs (J1+J3, J2+J4) there will be a performance hit.
 
   Don't stuff one riser with modules (especially double-sided) and leave the other blank. It *hates* imbalance on the memory drivers. Try to organize them the way to achieve a balanced load on *both* memory risers by having equal number of chips per pair, then on both risers. Certain releases of the Mod. 90 had problems with the double-sided SIMMs - especially with the 8MB ..

   [Ed.] Please genuflect while absorbing the riser/slot illustration. Remember, for interleaved configuration, you place matched speed/size SIMMs in A1-B1, A2-B2, and so on. Please note that the SIMM pairs do NOT cross between memory risers. The Model 95 uses separate A and B banks (A1, A2, A3, A4 then B1, B2, B3, B4) while the Model 90 uses both banks on both cards, A1, A2, B1, B2 then A3, A4, B3, B4).

8590 Memory Parity Errors / Configuration H095511

Unbalanced loading of SIMMs may cause parity errors when using four or more  SIMMs.

Classify each SIMM as HIGH or LOW LOAD based on the following:
A. Count total modules (chips) on both sides of SIMM.
B. If 12 or less, the SIMM is LOW LOAD.
C. If greater than 12, the SIMM is HIGH LOAD.

This chart shows number of modules (chips) on each type of SIMM and its LOAD:

SIZE

Modules

LOAD

2MB

10

LOW

4MB

9-12

LOW

2MB

18-24

HIGH

8MB

18-24

HIGH


If the SIMMs are either all HIGH LOAD, or all LOW LOAD, then install in both memory riser cards and exit this procedure.


Memory SIMM Configuration Procedure:
NOTE: For this procedure, memory will always be installed in matched pairs starting with J1&J3 then J2&J4 on memory riser cards. Riser card in J11 will always be fully populated first.

1. Install low load matched pair in J2&J4 of memory riser in J11.


2. If only 4 SIMMs will be installed, go to step 3, if not, proceed with step 4.


3. Install two remaining matched SIMMs in J1&J3 of memory riser in J11 and exit.


4. For six SIMMs go to step 5 (EXAMPLE 1) for eight SIMMs go to step 7 (EXAMPLE 2)


5. For a LOW LOAD matched pair, install in J1&J3 of riser J11 and go to step 6. If remaining memory is HIGH LOAD then install a matched pair in J1&J3 of riser in J11.


6. Install remaining HIGH LOAD matched pair in J1&J3 of memory riser in J14 and exit.


7. Install a HIGH LOAD matched pair in J1&J3 of memory riser in J11.


8. If remaining memory is all HIGH or all LOW, install on memory riser in J14 and exit.


9. Install remaining LOW LOAD matched memory in J2&J4 and HIGH LOAD matched memory in J1&J3 of the memory riser in J14 and exit.

The following are examples of how to implement this procedure:

EXAMPLE1:

Riser J11

Riser J14

J4

2MB LOW

J4

 

J3

2MB LOW

J3

8MB HIGH

J2

2MB LOW

J2

 

J1

2MB LOW

J1

8MB HIGH

Connector

 

Connector

 


This system has six SIMMs and it has been determined that the four 2MB SIMMs are LOW LOAD and the two 8MB SIMMs are HIGH LOAD. According to this procedure, no change is required.

EXAMPLE 2:

Riser J11

Riser J14

J4

2MB LOW

J4

8MB HIGH

J3

2MB LOW

J3

8MB HIGH

J2

2MB LOW

J2

8MB HIGH

J1

2MB LOW

J1

8MB HIGH

Connector

 

Connector

 

 

The system above has eight SIMMs, four HIGH LOAD and four LOW LOAD. The system should be reconfigured as shown below in example 3:

EXAMPLE 3:

Riser J11

Riser J14

J4

2MB LOW

J4

2MB LOW

J3

8MB HIGH

J3

8MB HIGH

J2

2MB LOW

J2

2MB LOW

J1

8MB HIGH

J1

8MB HIGH

Connector

 

Connector

 

 

ECA084 - Model 90 Memory Riser Card
   If memory riser card FRU P/N 33F4905 is populated with "MIXED SIMMs" and is experiencing any of the following errors:  DOS NMI, OS/2 TRAP 0002, POST, or diagnostic memory errors, replace both memory riser cards with new FRU P/N 81F8823 (two required).

NOTE:  "MIXED SIMMs" is defined as SIMMs with 12 modules or more per SIMM, mixed with SIMMs having less than 12 modules per SIMM mounted on the same riser card.  If FRU P/N 81F8823 is already installed, this ECA is not applicable.


Original scan from Al Savage out on the left coast

   The "bad" riser (33F4905) has six electrolytic capacitors on the front. The "good" riser (81F8823 or 81F8827) has only the silk screen outlines for the caps (also a lot more SMD resistors and caps on the back). Both risers have metal clips and white SIMM sockets.

Error 201
    Error code 201 says "Reseat system board memory" and can afflict the planar as well as the memory only. I would suggest to remove the memory risers, reseat all modules, plug them back and see if they are seated properly. 

    I would also suggest that you start with one single pair of matching memory modules in the connectors J1 + J3 on riser J11 - the one closer to the processor board. This is just to test out if your problem is memory- or planar related.

    If the machine comes up fine (counts memory) - install the next pair in sockets J1 + J3 in Riser J14 - the on closer to the power supply to keep balanced load of the memory decoder lines. As I wrote: the Mod. 90 has a sensible feeling for imbalanced memory modules and may "spin out" with somewhat strange and unexplainable errors by no obvious reason. There once was a recommendation from IBM on that topic and they explicitly mentioned it for the Mod. 90 - particularly for those cases where double-sided memory modules are used (which put a higher load on the decoder lines). 

Memory Expansion Boards
   You can't. Sort of. The 90 (and 95) does not cache expansion board memory. So in addition to the overhead in negotiating for control of the microchannel bus, you have to give up the advantage of the 486 cache...

WARNING! --------------------------------------------------~
Memory adapters on the Micro Channel are NOT supported, although they may work. However, it is strongly recommended not to use them as they will significantly degrade the overall performance of the system, as memory on the Micro Channel is not cached.

NOTE: Memory expansion adapters are only supported on 8590 special bid systems with 386 complexi (FRU P/N 33F8454) Known -402 are from WorldCom, Aetna, Royal Bank.

Ed. With the advent of eight SIMM sockets and higher density SIMMs, the need for memory cards fell off dramatically....



AdapterId FF6F Built In Features (Model 90)

Total System Memory
   Installed Memory. . . . . . . . . . . . : nnnnKB (nn.nMB)
   Useable Memory  . . . . . . . . . . . . : nnnnKB (nn.nMB)

Built In Features
   Installed Memory. . . . . . . . . . . . : nnnnKB (nn.nMB)
   Diskette Drive 0 Type . . . . . . . . . : 1.44MB 3.5”
   Diskette Drive 1 Type . . . . . . . . . : Not Installed
   Diskette Drive 2 Type . . . . . . . . . : Not Installed
   Math Coprocessor. . . . . . . . . . . . : Installed
   Display F1 prompt to access System Pro. : Yes [T4 only?]
   Serial Port   . . . . . . . . . . . . . : SERIAL_1  (DB25 port!)
   Serial Transmit Arbitration Level . . . : Shared 4
   Serial Receive Arbitration Level. . . . : Shared 3
   Parallel Port . . . . . . . . . . . . . : PARALLEL_1
   Parallel Port Arbitration Level . . . . : Shared 7
   Preempt Enable/Disable  . . . . . . . . : Enable
   Video I/O Address . . . . . . . . . . . : Instance x: nnnnh – nnnnh
   Video ROM Address Space . . . . . . . . : Annnn – Annnn
   Video Arbitration Level . . . . . . . . : Arbitration Level x
   Video Fairness. . . . . . . . . . . . . : Fairness xx
   Useable System Board Memory . . . . . . : Parity [T3, T4 only]
   Bypass System Programs on Error . . . . : Disabled [T4 only]
   Processor  .  . . . . . . . . . . . . . : Pentium 60 [T4 only?]

Slot 1 – (Card Name)

Slot 2 – (Card Name)

Slot 3 – (Card Name) This is an AVE slot, XGA and XGA2 will not fit...

Slot 4 – (Card Name)

Planar Device 5 – Integrated Fixed Disk and Controller [T0 only]
   DMA Arbitration Level . . . . . . . . . : Level x
   DMA Burst Pacing Interval . . . . . . . : xx Microseconds
   DMA Pacing Control . . . .  . . . . . . : Disabled
   Time To Release  . . . . .  . . . . . . : x Microseconds
   Fairness On/Off  . . . . .  . . . . . . : On
   Primary/Alternate Port Addresses  . . . : Primary

Planar Device 6 – Serial Port No. 2 (DB9 Port!)
   Serial Port   . . . . . . . . . . . . . : SERIAL_2
   Serial Transmit Arbitration Level . . . : Shared x
   Serial Receive Arbitration Level. . . . : Shared x

Planar Device 7 – Integrated Fixed Disk and Controller [T0 only]
   DMA Arbitration Level . . . . . . . . . : Level x
   DMA Burst Pacing Interval . . . . . . . : xx Microseconds
   DMA Pacing Control  . . . . . . . . . . : Disabled
   Time To Release . . . . . . . . . . . . : x Microseconds
   Fairness On/Off . . . . . . . . . . . . : On
   Primary/Alternate Port Addresses  . . . : Alternate

Planar Device 8 – Empty


System Memory Explained 

Total System > Installed Memory = Planar plus memory expansion adapter
    [minus defective or misconfigured memory]

Total System > Useable Memory = Installed minus any ROM shadowing
    [minus defective or misconfigured memory]

Built In Features> Installed Memory = Planar memory only
   [minus defective or misconfigured memory]

Diskette Drive x Type 
   1.44MB, 2.88MB

Serial Port [DB25 or DB9 Port]
   Serial 1 - 8 or disabled.  Must be enabled if using an ASCII terminal as a system console.
      <"SERIAL 1 (03f8h-03ffh 083f8h-083ffh, int 4)>, 2 (2f8-2ff 82f8-82ff, 3), 3 (3220-3227 b220-b227, 3), 4 (3228-322f b228-b22f, 3), 5 (4220-4227 c220-c227 3), 6 (4228-422f c228-c22f  3), 7 (5220-5227 d220-d227 3), 8 (5228-522f d228-d22f 3),  Disabled

Serial Transmit Arbitration Level
   Use any level. Shared with other devices. Dedicated, only this device can use that level.
      <"Shared 4" >, 3, 1, 0, 7, 6, 5, Dedicated 7, 6, 5, 4, 3, 1, 0, Disabled

Serial Receive Arbitration Level
   Use any level. Shared with other devices. Dedicated, only this device can use that level.
      <"Shared 3>, 1, 0, 7, 6, 5, 4, Dedicated 7, 6, 5, 4, 3, 1, 0, Disabled

Parallel Port
  Parallel 1 through 3 or disabled.
       <"PARALLEL 1"  (03bc-03bf 1278-127f int 7)>,  2 (0378-037f int 7), 3 (0278-027f int 7),  Disabled 

NOTE: PARALLEL_2 is the one Winblows calls LPT1!
NOTE: PARALLEL_1 includes the I/O range 1278-127D to support DMA operations. DMA can be turned off via Arbitration Level if it is incompatible.

Parallel Port Arbitration Level
   Use any level.  Shared, other devices can use same level.  Dedicated, only this device can use that level.  <Disabled> sets port in compatibility mode [known as bidirectional].
      <"Shared 7">, 6, 5, 4, 3, 1, 0, Dedicated 7, 6, 5, 4, 3, 1, 0, Disabled

NOTE: IBM developed the DMA parallel port prior to industry standards being developed. If you are using a parallel port connected device and it is misbehaving, Disable the Arbitration Level. Sad but true....

Preempt Enable/Disable
   Complex CPU can preempt continuous data transfers by other devices for its use of MC.
     <"Enable">, Disable

Video I/O Address
  Address range for display controller registers, and location of video coprocessor registers.
        <"Instance 6: 2160h - 216Fh">, 1 (2110-211F), 2 (2120-212F), 3 (2130-213F), 4 (2140-214F), 5 (2150-215F)

Video ROM Address Space [Slot 0 in "Memory Map"]
   Memory address range used for system video ROM.
        <"C0000-C1FFF" >, C2000-C3FFF, C4000-C5FFF, C6000-C7FFF, C8000-C9FFF, CA000-CBFFF, CC000-CDFFF, CE000-CFFFF, D0000- D1FFF, D2000-D3FFF, D4000-D5FFF, D6000-D7FFF, D8000-D9FFF, DA000-DBFFF, DC000-DDFFF, DE000-DFFFF

Video Arbitration Level
   Video sub-system arbitration levels.
        <"Arbitration level 13">, 12, 11, 10, 9, 8, 14

Video Fairness
   Whether video sub-system coprocessor follows fairness algorithm for bus usage.
        <"Fairness On">, Off

ADPItem 1 Usable System-Board Memory   (Exec)
   Type of Usable Memory on planar.  Either parity or error-correcting-code (ECC)

Bypass System Programs on Error [T4 only]
  Enabled Disabled

Processor (Exec)
   Pentium 60 [T4 only?]



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