Model 90 Base Fan Size

[Tomas Slavotinek]

Remember the talks about the "extra" hole in the fan area of the Model
90 chassis?

https://ardent-tool.com/9590/Common.html#Base_Fan
https://ardent-tool.com/9590/90_Ground_Shields.jpg

It doesn't align with the bottom screw of the 80 mm intake fan and it's
completely missing on the early units... so what's going here?

Well, the answer was right in front of us the entire time.

First, here's a photo of the 80 mm fan:
https://ardent-tool.com/9590/90_Fan_and_Speaker_02.jpg

Notice how it covers only the processor complex and *two* of the MCA
slots. The other two slots get no direct airflow from the fan.

Now compare it to this photo:
https://ardent-tool.com/9590/90_FW_SCSI_Cable_Routing.jpg

The fan is actually larger! It covers the complex and *three* MCA slots,
leaving only one with no direct airflow...

This larger fan *should* be 92 mm x 92 mm (same as in the PSU) and the
bottom mounting hole *should* align perfectly with the additional round
access hole, but this needs a confirmation...

I don't know when this change was made and whether it's related to the
complex type or machine configuration in any way, but clearly not all
units with the modified chassis have the larger fan.

If you have a Model 90 please check what kind of intake fan it has. If
it's the larger one please post what the fan sticker says (manufacturer,
model, current rating...). You will probably have to remove the adapters
to be able to read it. Please also check if the bottom mounting screw
aligns with the lower *round* hole in the front of the chassis.

The later (9590) units with the blue badge are more likely to have the
larger fan (or perhaps it's even exclusive to these units).

[Tomas Slavotinek]

This machine also has the larger fan:
https://youtu.be/fNDu9qFhzOo?t=26
(blue badge "PS/2 90", Type 2 complex)

Dave's NOS 8590-402 has the extra hole but the smaller fan shroud and
*no* fan at all (not needed for the 386 I guess, it also has only one
mem. riser):
https://youtu.be/Co3-EdpO7Kk?t=3061
(gray badge "PS/2 Model 90 XP 386", 17 Dec 1991?)

Clint's machine has the smaller (80 mm) fan, not sure about the
additional hole (I don't think it's visible anywhere in the video):
https://youtu.be/Bhvfa3zRaGs?t=104
(gray badge "PS/2 Model 90 XP 486", upgraded to Type 4 "N")

John's 8590 has the larger fan:
http://john.ccac.rwth-aachen.de:8000/alf/ps2_8590t1/
(gray badge, Type 1 complex)

John's second 8590, larger fan:
http://john.ccac.rwth-aachen.de:8000/alf/ps2_8590/
(gray badge "PS/2 Model 90 XP 486", Type 2 complex)

Random 9590-ALA case, shroud for the larger fan:
https://www.ebay.com.my/itm/IBM-PS-2-Case-for-Model-90-XP-486-9590-ALA-/393050064587
(gray badge "PS/2 Model 90 XP 486", ALA - Type 2 "L")

Well the larger fan seems to be rather common, but I don't see a pattern
here yet...

[IBMMuseum]

> John's 8590 has the larger fan:
> http://john.ccac.rwth-aachen.de:8000/alf/ps2_8590t1/
> (gray badge, Type 1 complex)
>
> John's second 8590, larger fan:
> http://john.ccac.rwth-aachen.de:8000/alf/ps2_8590/
> (gray badge "PS/2 Model 90 XP 486", Type 2 complex)

"John" being Alfred Arnold - I was having trouble pulling up his site (I thought it was an HTTP vs. HTTPS thing at first), but my network here is locked down for TCP ports.

[Tomas Slavotinek]

Ah yes, my brain got distracted by the URL... sorry about that.

[Louis Ohland]

Doesn't "alf" stand for Alien Life Form?

[JWR]

Yep, from Melmak.

--
Jelte,
Admirer of the letter of IBM with blue Ishiki

[JWR]

Hi Tom,

To start with your last remark: the three 9590's I've got are all blue-badged and all have 92mm fans (with double fingerguards).
Pictures are her on csiph.com (ftp):

/incoming/ps2mad/pics/9590-ALA
/incoming/ps2mad/pics/9590-ALF
/incoming/ps2mad/pics/9590-OLA
Look at the 2021-pics.

As you can see (never mind the dust-devils), the round holes line up (almost) perfectly with the fanscrews.
All three fans have ASSY NO: 10G3544 datecode 6-93 (ALA), 43-92 (ALF) and 51-92 (OLA)

Other specs are:
9590-ALA (running W98SE):
----------------------------------- Machine -----------------------------------
Model/submodel: f8 29 (BIOS revision: 03)
Planar: ID ff6fh; disabled
Description: Model 90 486DX/50 (type 3A)
This configuration has not been tested
----------------------------------- Memory ------------------------------------
Connector A1: 8MB 70ns parity
Connector B1: 8MB 70ns parity
Connector A2: 8MB 70ns parity
Connector B2: 8MB 70ns parity
Connector A3: 8MB 70ns parity
Connector B3: 8MB 70ns parity
Connector A4: 8MB 70ns parity
Connector B4: 8MB 70ns parity
-------------------------------- Slot contents --------------------------------
Slot 1: ID: 8effh; IBM PS/2 SCSI Adapter with cache (32/16-bit); enabled
POS bytes: f1 fc a0 ff ff ff
Slot 2: ID: ffffh; empty
Slot 3: ID: ffffh; empty
Slot 4: ID: ffffh; empty
-------------------------------- System board ---------------------------------
Onboard video: disabled
Onboard video equivalent: IBM XGA Display Adapter/A
Diskette: disabled; port 3f0h; irq 6


9590-ALF (running a Danish W95):
Sorry, but I don't have a testreport of this 9590 :((
But I did have a good look (back in the day when I got it) and this is the available info:
----------------------------------- Machine -----------------------------------
Description: Model 90 486DX2/?? (type ??)
----------------------------------- Memory ------------------------------------
Connector A1: 8MB 70ns P 71F7011
Connector B1: 4MB 70ns P 31F2314
Connector A2: 4MB 70ns P 31F2314
Connector B2: empty (!)
Connector A3: empty
Connector B3: empty
Connector A4: empty
Connector B4: empty
-------------------------------- Slot contents --------------------------------
Slot 1: ID: 8effh; IBM PS/2 SCSI Adapter with cache (32/16-bit)
Slot 2: ID: ----h; XGA-2
Slot 3: ID: ----h; Borsu Bernouilli
Slot 4: ID: ----h; HP EtherTwist
-------------------------------- System board ---------------------------------
N/A


9590-OLA (running W95 SR1):
----------------------------------- Machine -----------------------------------
Model/submodel: f8 3f (BIOS revision: 05)
Planar: ID ff6fh; disabled
Description: Model 90 486DX2/50 (type 2B)
This configuration has not been tested
----------------------------------- Memory ------------------------------------
Connector A1: 4MB 70ns parity
Connector B1: 4MB 70ns parity
Connector A2: 4MB 70ns parity
Connector B2: 4MB 70ns parity
Connector A3: empty
Connector B3: empty
Connector A4: empty
Connector B4: empty
-------------------------------- Slot contents --------------------------------
Slot 1: ID: 8effh; IBM PS/2 SCSI Adapter with cache (32/16-bit); enabled
POS bytes: f1 fc a0 ff ff ff
Slot 2: ID: ffffh; empty
Slot 3: ID: ffffh; empty
Slot 4: ID: ffffh; empty
-------------------------------- System board ---------------------------------
Onboard video: disabled
Onboard video equivalent: IBM XGA Display Adapter/A
Diskette: disabled; port 3f0h; irq 6

HTTH,

[Tomas Slavotinek]

Thanks for the info and especially for the photos!

(Reuploaded here: https://www.ardent-tool.com/photos/jelte/)

So, looks like there are at least 3 different "configurations":
-8595-402 XP 386 - 80 mm shroud, no fan, no complex baffle
[nothing gets direct airflow]
-early 8595 XP 486, possibly some 9595 - 80 mm fan
[complex + 2 MCA slots get direct airflow]
-later 8595 and most or all 9595 - 92? mm fan
[complex + 3 MCA slots get direct airflow]

Can you please take some photos of the fan manufacturer sticker? (the
one that covers the fan bearing - it's hard to access, but you should be
able to see it through the MCA openings if you remove some of the
cards...) Or at least confirm the fan dimensions (my 8595 doesn't even
have the additional round hole, so I can't measure it...).

If there is a P/N anywhere on the fan/card support assembly, please note
it as well (though based on some other photos, it's probably hidden
under the planar... so not really worth the effort).

Also, when probing the 5560 planar I've noticed that the intake fan is
powered from the negative -12 V rail (positive lead goes to ground,
negative to -12 V). It's the same for the 8590 planar. Curious...