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IBM 9595 Motherboard

ButINeededThatName

Experienced Member
Joined
Nov 29, 2018
Messages
176
Location
Fort Wayne, IN
It's likely your board just has faulty capacitors and that you could find the bad ones with a multi-meter and replace them yourself (if you know how to solder anyways).

If not though and if another member on here doesn't have one to spare there are a couple up on FeeBay, for the FeeBay premium of course...

This one is up in Canada for $200...
https://www.ebay.com/itm/92F2623-06H3951-06H3951R-IBM-505-SYS-BD-SVR-95-500-8641/350288902162?hash=item518ed87812:g:SCoAAMXQcVNQ57YC

And this one is in the UK for $150 with shipping...
https://www.ebay.com/itm/IBM-92F2623-PC-used/283537209531?epid=1149140040&hash=item42042278bb:g:G74AAOSwglJdHeTu

Alternatively, you could post a wanted ad in the "Vintage Computer Services Offered / Needed" section of the forums and see if anyone would be willing to troubleshoot and repair your board for you.
 
Last edited:

Culbrelai

Experienced Member
Joined
Jun 18, 2017
Messages
65
Location
SE Michigan, USA
It's likely your board just has faulty capacitors and that you could find the bad ones with a multi-meter and replace them yourself (if you know how to solder anyways).

If not though and if another member on here doesn't have one to spare there are a couple up on FeeBay, for the FeeBay premium of course...

This one is up in Canada for $200...
https://www.ebay.com/itm/92F2623-06H3951-06H3951R-IBM-505-SYS-BD-SVR-95-500-8641/350288902162?hash=item518ed87812:g:SCoAAMXQcVNQ57YC

And this one is in the UK for $150 with shipping...
https://www.ebay.com/itm/IBM-92F2623-PC-used/283537209531?epid=1149140040&hash=item42042278bb:g:G74AAOSwglJdHeTu

Alternatively, you could post a wanted ad in the "Vintage Computer Services Offered / Needed" section of the forums and see if anyone would be willing to troubleshoot and repair your board for you.

Yeah I looked on ebay, both of those are really overpriced, only a few years ago they sold for $50-60 and a seller I offered wanted $125 minimum. No thanks lmao

The entire saga is here https://groups.google.com/forum/#!topic/comp.sys.ibm.ps2.hardware/1kv-wRmqzG8

of me trying to find out what is wrong with it.

It's very strange, but since you fixed what like half a dozen 9595s maybe you can help. Long story short, I bought the 9595 off ebay, and it worked just fine until I went to change the battery (because I figured it had been in there the past 20 years and was likely to die soon)

After I did that, was when it started acting strange. Getting stuck when the LED display was at "CP 01" with no video, it only recovers from this if I take the battery out for a fair bit and repower. When I configure the computer again with the reference disk I get some errors, after the computer is powered off for a bit, it sticks on CP 01 again and the cycle repeats.
https://i.imgur.com/cBIo015.jpg
This one with the diagnostic disk

https://i.imgur.com/LRNdPFb.jpg

I might finally invest in a multimeter (and soldering iron) since replacement boards are so darn expensive. Gonna give the board a good cleaning first. I think I may see some leaking capacitors - some of them have white residue on the tops of the cans. They're nichicon caps which are a reputable brand but I suppose time makes fools of them all? It's difficult to get a clear picture of the residue.

One of the Dallas chips has some white residue on the fingers

https://i.imgur.com/bBqBSye.jpg


Other than the white residue on the dallas chip and on a few of the caps the board looks alright... fairly clean really.
 

ButINeededThatName

Experienced Member
Joined
Nov 29, 2018
Messages
176
Location
Fort Wayne, IN
Yeah I looked on ebay, both of those are really overpriced, only a few years ago they sold for $50-60 and a seller I offered wanted $125 minimum. No thanks lmao

The entire saga is here https://groups.google.com/forum/#!topic/comp.sys.ibm.ps2.hardware/1kv-wRmqzG8

of me trying to find out what is wrong with it.

It's very strange, but since you fixed what like half a dozen 9595s maybe you can help. Long story short, I bought the 9595 off ebay, and it worked just fine until I went to change the battery (because I figured it had been in there the past 20 years and was likely to die soon)

After I did that, was when it started acting strange. Getting stuck when the LED display was at "CP 01" with no video, it only recovers from this if I take the battery out for a fair bit and repower. When I configure the computer again with the reference disk I get some errors, after the computer is powered off for a bit, it sticks on CP 01 again and the cycle repeats.
https://i.imgur.com/cBIo015.jpg
This one with the diagnostic disk

https://i.imgur.com/LRNdPFb.jpg

I might finally invest in a multimeter (and soldering iron) since replacement boards are so darn expensive. Gonna give the board a good cleaning first. I think I may see some leaking capacitors - some of them have white residue on the tops of the cans. They're nichicon caps which are a reputable brand but I suppose time makes fools of them all? It's difficult to get a clear picture of the residue.

One of the Dallas chips has some white residue on the fingers

https://i.imgur.com/bBqBSye.jpg


Other than the white residue on the dallas chip and on a few of the caps the board looks alright... fairly clean really.

Hey... I know you! I'm the fellow Redditor that explained what the CP codes you were getting meant. Sorry to hear you're still having trouble with it.

So yeah, according to the second photo the system is effectively telling you something on your system board has died. My first question is this: Googling the FRU your system lists in picture two for the system board brings up the result for the older style board for the 8595, not the 9595. The differences are minor, though I would like to know which you have and what type complex you're trying to use with it. The older has only one serial and parallel port on the back and can't use the Type 4 Pentium complexes to their full potential and the newer has two serial and two parallel ports on the back and will barf up a 172 error code if you stick anything other than a Type 4 Pentium complex into it (I'm not sure if that includes the 50MHz M complex though).

From how you've explained the state of your system board and the issues you're having I can really only give you an educated guess as to what's happening...

So, that white residue may very well be corrosion. I've seen it in several systems that have those god awful NiCad barrel batteries that when they go bad, usually just vomit acid all over the board. What's even worse is that when there's an appreciable amount of it and if given enough time, it will "creep" up wires and traces to other parts of the board (I have a 5155 portable that this happened in) and if it's bad enough just warrants replacing the whole damn board. Anyways, my best guess is some of the capacitors on the same circuit as the clock / battery have lost their lunch, but you didn't see any errors other than 161 / 163 as the battery was dead and those circuits were thus unpowered, concealing the larger issue (failed electrolytics). Most likely when you installed a new battery and powered said circuits you simply just brought the real issue to light. This also would explain why this odd behaviour stops after you remove the battery and let it sit awhile. If I were you I'd definitely just replace all of the capacitors on that section of the planar and see where that gets you.

By the way, if it's all right with you I'm going to qoute this whole conversation and post it in the "Later PCs" section of this forum as that's really the appropriate place to discuss troubleshooting for this system and you may get some more advice from other members there.
 

Lutiana

Administrator
Staff member
Joined
Mar 26, 2009
Messages
3,203
Location
Dublin, CA USA
By the way, if it's all right with you I'm going to qoute this whole conversation and post it in the "Later PCs" section of this forum as that's really the appropriate place to discuss troubleshooting for this system and you may get some more advice from other members there.

No need. I moved it, and tweaked the title.
 

Culbrelai

Experienced Member
Joined
Jun 18, 2017
Messages
65
Location
SE Michigan, USA
Hey... I know you! I'm the fellow Redditor that explained what the CP codes you were getting meant. Sorry to hear you're still having trouble with it.

So yeah, according to the second photo the system is effectively telling you something on your system board has died. My first question is this: Googling the FRU your system lists in picture two for the system board brings up the result for the older style board for the 8595, not the 9595. The differences are minor, though I would like to know which you have and what type complex you're trying to use with it. The older has only one serial and parallel port on the back and can't use the Type 4 Pentium complexes to their full potential and the newer has two serial and two parallel ports on the back and will barf up a 172 error code if you stick anything other than a Type 4 Pentium complex into it (I'm not sure if that includes the 50MHz M complex though).

From how you've explained the state of your system board and the issues you're having I can really only give you an educated guess as to what's happening...

So, that white residue may very well be corrosion. I've seen it in several systems that have those god awful NiCad barrel batteries that when they go bad, usually just vomit acid all over the board. What's even worse is that when there's an appreciable amount of it and if given enough time, it will "creep" up wires and traces to other parts of the board (I have a 5155 portable that this happened in) and if it's bad enough just warrants replacing the whole damn board. Anyways, my best guess is some of the capacitors on the same circuit as the clock / battery have lost their lunch, but you didn't see any errors other than 161 / 163 as the battery was dead and those circuits were thus unpowered, concealing the larger issue (failed electrolytics). Most likely when you installed a new battery and powered said circuits you simply just brought the real issue to light. This also would explain why this odd behaviour stops after you remove the battery and let it sit awhile. If I were you I'd definitely just replace all of the capacitors on that section of the planar and see where that gets you.

By the way, if it's all right with you I'm going to qoute this whole conversation and post it in the "Later PCs" section of this forum as that's really the appropriate place to discuss troubleshooting for this system and you may get some more advice from other members there.

I'm using a P66 complex, 16 MB RAM (from an 8590, since this computer had no ram when I got it from ebay) a Buslogic BT646, XGA-2 and a 4GB HDD.

I'm going to test the P66 in the 8590 later today to rule that out, the 8590 works it just doesn't have a case or floppy cable.

XGA-2 and BusLogic are both known working (from using them in a model 80 for a hot while)

The case says its a "9595-OLG" and the motherboard's FRU is 33F5717.

Anyone have any recommendations for soldering irons for a beginner? I watch a LOT of electronics repair videos, but I've never done it myself (EEVBlog, AkuBkuku...)

It's no big loss if I screw up this cactus of a board anyway I suppose.
 

ButINeededThatName

Experienced Member
Joined
Nov 29, 2018
Messages
176
Location
Fort Wayne, IN
I'm using a P66 complex, 16 MB RAM (from an 8590, since this computer had no ram when I got it from ebay) a Buslogic BT646, XGA-2 and a 4GB HDD.

I'm going to test the P66 in the 8590 later today to rule that out, the 8590 works it just doesn't have a case or floppy cable.

XGA-2 and BusLogic are both known working (from using them in a model 80 for a hot while)

The case says its a "9595-OLG" and the motherboard's FRU is 33F5717.

Anyone have any recommendations for soldering irons for a beginner? I watch a LOT of electronics repair videos, but I've never done it myself (EEVBlog, AkuBkuku...)

It's no big loss if I screw up this cactus of a board anyway I suppose.

Does it have one of each port (serial and parallel) on the rear or two of each? That way I know for certain what board type you have.
 

ButINeededThatName

Experienced Member
Joined
Nov 29, 2018
Messages
176
Location
Fort Wayne, IN
It has one of each

It sounds like your system doesn't have the original planar then (if it is in fact a 9595), as that coupled with the board's FRU means it's an 8595 planar. One more quick question; On your operator panel, does it just have a power LED and the power switch on the right side with the display on the left? Or does it have both a power, hard disk LED and power switch on the left side with the display on the right?
 

Culbrelai

Experienced Member
Joined
Jun 18, 2017
Messages
65
Location
SE Michigan, USA
It sounds like your system doesn't have the original planar then (if it is in fact a 9595), as that coupled with the board's FRU means it's an 8595 planar. One more quick question; On your operator panel, does it just have a power LED and the power switch on the right side with the display on the left? Or does it have both a power, hard disk LED and power switch on the left side with the display on the right?

Just a power led with display on the left
 

Culbrelai

Experienced Member
Joined
Jun 18, 2017
Messages
65
Location
SE Michigan, USA
Yeah, I do, it gets stuck on “0001 7100” with no video. Haven’t tried to cycle it by taking the battery out like the p66. What do you mean they can’t use a type 4 to its full potential? How so? Also, what is the FRU of an actual 9595 motherboard so I can change my ebay search =P
 

ButINeededThatName

Experienced Member
Joined
Nov 29, 2018
Messages
176
Location
Fort Wayne, IN
Yeah, I do, it gets stuck on “0001 7100” with no video. Haven’t tried to cycle it by taking the battery out like the p66. What do you mean they can’t use a type 4 to its full potential? How so? Also, what is the FRU of an actual 9595 motherboard so I can change my ebay search =P

Since the 9595 planar has additional I/O (the second serial and parallel port), the rear I/O opening on the 9595s are longer. You can stick a 9595 planar into an 8595 chassis, but you'd need to cut into the case to lengthen the I/O hole for the planar. You'd also need to either cut your rear plastic bezel the same way or buy a 9595 rear bezel. I believe you also need the operator panel from a 9595 (two LEDs, display on the right) with the thin ribbon cable (or just the cable itself) which plugs directly into a socket on the Type 4 complexes. Personally, I wouldn't cut into a machine to make it something it's not.

As for "Not utilizing a Type 4 to it's full potential" the Type 4 complexes have what's called the "Synchrostream Controller," which effectively allows the system bus to hit speeds up to 40Mb/s. The older 8595 planars don't support Synchrostream and therefore you won't see the faster bus speeds.
 

ardent-blue

Experienced Member
Joined
Jan 2, 2015
Messages
362
As for "Not utilizing a Type 4 to it's full potential" the Type 4 complexes have what's called the "Synchrostream Controller," which effectively allows the system bus to hit speeds up to 40Mb/s. The older 8595 planars don't support Synchrostream and therefore you won't see the faster bus speeds.

8595 and 9595-0LF planars are single serial. As always, any system can be upgraded at any point, so what is inside may be very different than the type-model sticker.

Oddly, all Model 90 and 95 planars support 100nS streaming.
http://ps-2.kev009.com/ohlandl/complexes/complex_complexities.html

The SynchroStream controller is a single chip that replaces 5 components on the M and N complexi [all Pentium T4 have SSC]. My reading suggests SSC will work on any planar, all the guts are on the complex.

http://ps-2.kev009.com/ohlandl/parts/streaming.html

http://ps-2.kev009.com/ohlandl/parts/define.html#Streaming_data

Streaming data transfer.
The streaming-data procedure allows high-speed transfer of data between bus masters and slaves. This procedure supports high-speed transfers of large blocks of data for devices such as hard disk drives and network adapters.
The streaming-data procedure transfers blocks of sequentially stored data. In basic data-transfer operations, a target address is assigned for every byte of data that is transferred. The streaming-data procedure assigns a target address only to the first byte of data, and the rest of the data in the block follows in sequence and is assigned to sequential addresses. A streaming-data transfer operation takes 100 nanoseconds to send 4 bytes of data. This is a data-transfer rate of 40 million bytes per second, which is twice as fast as basic data-transfer operations.
The Micro Channel bus has 32 data lines and 32 address lines. During streaming-data transfer operations, the 32 address lines are used only at the beginning of a transfer cycle. Then they remain idle for the rest of the cycle. The multiplexed streaming-data procedure uses the address bus as another 32-bit data bus, allowing data to be transferred 64 bits at a time.

SynchroStream controller which uses IBM's most advanced technology packaging to integrate 5 major chips (memory, I/O, DMA controllers, FIFO buffers, ECC logic) into one chip. This technology allows the high-speed interconnects and large streaming pipes that form the SynchroStream engine to provide state-of-the-art performance. The SynchroSteam controller synchronizes data traveling between major subsystems and allows it to stream in parallel, at full bandwidth, to each subsystem concurrently.

At the heart of the computer, data is moving continually between processor, cache, main memory and the Micro Channel. Typically there is a single path to memory, so fast devices like processors have to wait for much slower I/O devices, slowing down the performance of the entire system to the speed of the slowest device. The IBM SynchroStream controller was designed to overcome this problem. It synchronizes the operation of fast and slow devices and streams data to these devices to ensure all devices work at their data at their optimum levels of performance.
Synchrostream is an intelligent device in that it predicts what data the devices will need and loads it from memory before it is requested. When the device wants the data, it is presented to it from the IBM SynchroStream controller and the device can continue working immediately, as it does not have to wait for the data to be collected from memory. When devices are moving data into memory, the IBM SynchroStream controller holds the data, and writes it to memory when it is most efficient to do so. Since devices are not moving data to and from memory directly, but to the SynchroStream controller, each device has its own logical path to memory. Devices do not have to wait for other slower devices.
The SynchroStream engine operates by using a spinning valve that continuously forms different connections between pipes. Once a connection is made, data is streamed to the Micro Channel or processor at the highest possible rates. Parallel paths allow data to stream to multiple sources at the same time. The pipes even continue to stream after the connection is changed. Data is always streaming to the Micro Channel and processor, allowing them to operate at full bandwidth.
IBM used the latest in chip design technology to integrate all SynchroStream functions on a single chip, improving performance dramatically by not having to move data between chips. The IBM SynchroStream controller uses a single RISC-like chip architecture to move data fast and efficiently between memory and requesting devices, as shown in Figure 8.
 

ardent-blue

Experienced Member
Joined
Jan 2, 2015
Messages
362
Since the 9595 planar has additional I/O (the second serial and parallel port), the rear I/O opening on the 9595s are longer. You can stick a 9595 planar into an 8595 chassis, but you'd need to cut into the case to lengthen the I/O hole for the planar. You'd also need to either cut your rear plastic bezel the same way or buy a 9595 rear bezel. I believe you also need the operator panel from a 9595 (two LEDs, display on the right) with the thin ribbon cable (or just the cable itself) which plugs directly into a socket on the Type 4 complexes. Personally, I wouldn't cut into a machine to make it something it's not.

http://ps-2.kev009.com/ohlandl/9595/9595_Planar.html#Hacking_8595
 

Culbrelai

Experienced Member
Joined
Jun 18, 2017
Messages
65
Location
SE Michigan, USA
Alright, update time: Got a new motherboard for cheap courtesy of ButINeededThatName

First boot, was fine. Went to go low level format the HDD, was taking too long so I powered it off.

Go to power it back on this morning, it turns on but no video, no CP codes at all (operator panel is blank)

Specs are the following:

66MHZ Pentium
3com Etherlink III
XGA-2
BusLogic BT-646 SCSI controller

16 MB RAM

Now this could be a case of bad caps you think? Or what? 486 complex doesn't cause it to come alive again either.
 

ardent-blue

Experienced Member
Joined
Jan 2, 2015
Messages
362
Alright, update time: Got a new motherboard for cheap courtesy of ButINeededThatName

First boot, was fine. Went to go low level format the HDD, was taking too long so I powered it off.

Go to power it back on this morning, it turns on but no video, no CP codes at all (operator panel is blank)

Specs are the following:

66MHZ Pentium
3com Etherlink III
XGA-2
BusLogic BT-646 SCSI controller

16 MB RAM

Now this could be a case of bad caps you think? Or what? 486 complex doesn't cause it to come alive again either.

Pull CR-2032. Move > J16 < to other outside pin. Pull BT-646 [plenty of frugal Corvettes around]. Pop battery in. Boot w/refdisk. It might / should come up in system programs. Toggling J10 forces system to use refdisk instead of saved configuration.

My suspicion is that either you chose an incompatible format [>1GB non-DOS or whatever] or BT-646 is mega-dorked? Report on Firmware / SCSI BIOS chips, like 3.38 / 4.70
 

g4ugm

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Feb 22, 2011
Messages
2,719
Location
NorthWest England (East Pondia)
Pull CR-2032. Move > J16 < to other outside pin. Pull BT-646 [plenty of frugal Corvettes around]. Pop battery in. Boot w/refdisk. It might / should come up in system programs. Toggling J10 forces system to use refdisk instead of saved configuration.

My suspicion is that either you chose an incompatible format [>1GB non-DOS or whatever] or BT-646 is mega-dorked? Report on Firmware / SCSI BIOS chips, like 3.38 / 4.70

Doesn't the BT646 have support for > 1GB? I have one on my PC Server...
 
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