Finding fault in early 90's ISA PC Card

[rx8pilot]

This post is semi-related to the thread I started for an old pick and place machine I got recently. https://www.eevblog.com/forum/reviews/finally-have-a-pick-and-place-on-the-way-quad-ivc/

Getting it up and running has revealed at least one bad PCB that is part of the vision system critical to the operation. In general, I would not bother reviving old-tech except for the fun of it. In this case, finding a fault in the board is quite important for me to be able to assemble PCB's without having to spend the money on contract manufacturing. This machine is full of PCBs that are hard to find so sharpening my PCB repair skills may be worth it.

The board is an ICOS MVS922 which is a controller that goes into an ISA slot of an industrial PC running wIn XP PRO. The original configuration was DOS based, the XP is an update that happened around 2009. The exact function of the board is unknown and I have not found any documentation at all. The company was purchased by KLA-Tencor and I have reached out to them to see if an archive exists. This is a commercial/industrial product so there is at least a small chance that some helpful docs exist. I have done some troubleshooting before, but my day to day is designing circuits. Without a schematic or block diagram it is hard to know where to start. The PC does not flag it as a problem, but the software cannot get a response from it. That is all I know. It worked for some time with the exact same PC configuration.

I pulled some of the datasheet on the components which are largely common discreet 5v logic, RS-485 differential driver/receivers, and some memory. I did a thorough visual inspection under a microscope. Everything looks good, no evidence of previous repairs. No thermal damage or cracks.

Checked the +5v to GND at around 170 Ohms which seemed a little low but not alarming. When powered up, it pulls 400ma (2 watts) which seems a little high with nothing connected to the I/O but not alarming. Nothing gets hot enough to find with my fingers and I do not have a thermal camera.

Powered it up outside of the PC and checked to verify the input to output relationships on the logic chips as best I could based on the data sheets. Nothing seems abnormal. Its hard to check flip-flops and shift registers in a simple way.

The chips that have the HEX value labels are unkown. At this time, I have not removed the stickers because these have a trade-in value if I were to replace it. A company called PPM keeps these and repairs them for $500 plus your trade in. Without a trade, it costs a lot more. If anyone has a guess what those might be doing without pulling the stickers, I am all ears.

Any suggestions where to go from here?

[wraper]

400 mA does not seem to be very high current at all, considering ICs used. 74F series consume a lot of current. 74LS consume significant current too. IDT7202 has 20 mA  max standby current, typ unknown. SN75179B has 57 mA typ. supply current, so those two will eat 114 mA alone.  But considering that there is oscillator, this board might be not in standby at all.

[PA0PBZ]

Just some suggestions:

 - Are you sure the jumpers are in the right position?

 - Does the card need an input signal to be initialised properly?

 - If you are stuck start with replacing the F374's and the ACT244's on the bus

[SeanB]

Labelled devices are Lattice Semiconductor logic gate arrays, used to fit what would otherwise be another board full of TTL into a single small package.

http://www.latticesemi.com/

At these are programmed and then have a protection fuse blown, it will be near impossible to see if they are working or not other than if they work properly. My bet is that they have the correct programming for these to replace faulty ones on the board, and simply change all of them on faulty boards, or do some simple tests to see which one is faulty, then reprogram it ( likely it has just had eeprom failing so a rewrite will make it work again).

If it was working then it is likely that Windows Plug-n-Pray might have reassigned an IRQ and IO address, and then it conflicted with this board because the board is not even aware of P-n-P, having jumpered settings. Check the registry that there are blocks fixed for the board, I get hazy, not having done much with hard wired non pnp boards and XP. 98 did need some massaging.

[wraper]

BTW why are you sure that this boards is faulty? Does the program give some error code? What I see that there is some serial connection going from the single connector on this board, so obviously it need to communicate something on the other end. There could be some jumper put in the wrong place too.

[rx8pilot]

Just some suggestions:
 - Are you sure the jumpers are in the right position?
 - Does the card need an input signal to be initialised properly?
 - If you are stuck start with replacing the F374's and the ACT244's on the bus

The jumpers have been confirmed by the company that pseudo supports these. The initialization fail is reported by the software with all signals attached. Since the error reporting is cryptic, it's hard to guess what is happening. Simply "Initialization: FAILED". It was previously working in this state from what I have been able to learn from the previous owner. Information is not 100% reliable though.

Are the 374 and 244 prone to failure?

BTW why are you sure that this boards is faulty? Does the program give some error code? What I see that there is some serial connection going from the single connector on this board, so obviously it need to communicate something on the other end. There could be some jumper put in the wrong place too.

It is still a guess based on the troubleshooting I have done on the PC side and what the technician at PPM has seen before. I have verified voltages on the ISA BUS and the driver is loading without reported errors. The serial connection is dual RS485 based on the drivers next to the connector.

Labelled devices are Lattice Semiconductor logic gate arrays, used to fit what would otherwise be another board full of TTL into a single small package.

http://www.latticesemi.com/

At these are programmed and then have a protection fuse blown, it will be near impossible to see if they are working or not other than if they work properly. My bet is that they have the correct programming for these to replace faulty ones on the board, and simply change all of them on faulty boards, or do some simple tests to see which one is faulty, then reprogram it ( likely it has just had eeprom failing so a rewrite will make it work again).

If it was working then it is likely that Windows Plug-n-Pray might have reassigned an IRQ and IO address, and then it conflicted with this board because the board is not even aware of P-n-P, having jumpered settings. Check the registry that there are blocks fixed for the board, I get hazy, not having done much with hard wired non pnp boards and XP. 98 did need some massaging.

I don't think this is a PNP card, the BIOS is forced to adssign IRQ10 and 11 to this "LEGACY ISA" card. I confirmed that it is physically connected to IRQ10 and 11 although I dont think it is actually using 11. The software is a custom re-write done long after this card was in service to make it work with XP.

I will take a closer look at the logic gate arrays, glad to know what those are. Thank you.

Also, I don't see any type of clock signal on the board with a quick pass with a scope. May mean nothing, but the crystal should be driving something but maybe it wont start without a PC connection.

continuing to search........ thank you for the tips!

[SeanB]

Crystal module could be faulty, check it has 5V and ground on 2 of the pins, then pop the scope on the other 2 pins, one will be a 20MHz something like square wave ( it will not look like one, just has to be close enough for a TTL gate to like it) and if it is not there you have your fault.

[PA0PBZ]

Are the 374 and 244 prone to failure?

Since it looks like there is a faillure to communicate with the card it could be that the part(s) sitting between the card and the pc are failing. If there is something wrong in the processing that the card should do I'd expect it to initialize properly but then being unable to do what it's supposed to do, resulting in the card outputting wrong data. I have seen and repaired ISA cards that had the bus drivers failing. Also, this is easy to do, much easier than trying to replace the gate arrays.

[SeanB]

Plug and pray always has an issue with legacy ISA cards, as it often will, for some reason, ignore the assignments and decide to allocate those used locations and interrupts, so the card and some other thing ( like a serial port or a second parallel port) stops working correctly.

[rx8pilot]

Crystal module could be faulty, check it has 5V and ground on 2 of the pins, then pop the scope on the other 2 pins, one will be a 20MHz something like square wave ( it will not look like one, just has to be close enough for a TTL gate to like it) and if it is not there you have your fault.

....checking. Will report.

Since it looks like there is a faillure to communicate with the card it could be that the part(s) sitting between the card and the pc are failing. If there is something wrong in the processing that the card should do I'd expect it to initialize properly but then being unable to do what it's supposed to do, resulting in the card outputting wrong data. I have seen and repaired ISA cards that had the bus drivers failing. Also, this is easy to do, much easier than trying to replace the gate arrays.

Definitely easy to replace....I will try crystal first followed by a DigiKey order for all the common logic and possibly the RS485 drivers.

[6502nop]

It looks to me (at 200% mag) that your oscillator is in backwards. Rotate it 180 degrees and see if it works...

{These tin can modules have one "sharp" corner, the others are rounded. The sharp is pin 1. If you look at the silk screen, you'll see that the sharp corner is the lower left, but the module shows all three rounded corners (I can't make out if the upper right of the can has the sharp edge from that angle). This would also explain no clock on the board, as the fourth pin is often NC.}

If it still doesn't work, it may be that the module was damaged from reversed polarity. No biggie, as they're only a dollar or two.

nop

[German_EE]

You should be able to get a clue about the fault before ordering parts.

1) Go to the XP Device Manager and make sure that the card can be seen. Does it show the correct IRQ?

2) Check for clock pulses using a scope.

3) The 74F374 and 74ACT244 chip pinouts are easy to find so follow the signal flow through, if you get an input then there should be an output.

4) Now it gets more difficult. Data on the rest of the 74 series chips can be found but you need experience in logic circuits. A 74F74 for example is a pair of flip flops so if you get inputs but no outputs it could be a faulty chip but it could also be a reset line that is stuck.

My guess is the 74F374 and 74ACT244 buffer chips.

Edit: Yes, it does look like the oscillator is the wrong way up.

[T3sl4co1l]

It's dead, Jim.

There's no way 400mA accounts for everything on there... at least, I don't see that it could.

Is this card really so precious?  It appears to be an old fashioned 8 bit RS-422/485 UART.  Evidence: SN75179? transceivers; the big IDT parts are FIFOs, and everything else is glue logic (bus latches, address decoding, etc.).  No clue what port(s) it shows up as, but I'd be willing to bet (knowing what the FIFOs are) that it wouldn't be hard to find what addresses make them blink.  Or just DEBUG the driver program and see what it IN/OUT's to!

Anyway, it doesn't seem like an unusual enough card not to have any generic substitutes.  You could probably save piles in repair cost if you can identify a sub.

All the CMOS parts should draw about bupkis current, at least until things start really cooking (to be fair, it does have an onboard crystal, so who knows what it does during startup/run?).  The 74F logic might be a bit more hungry, I forget, but there's only five of them.  The five PAL/GALs (almost certainly what the stickered chips are) could be pretty awful, now that I think of it, but they'd have to be doing, like... at least 50mA each, were they really that bad?

Tim

[T3sl4co1l]

You should be able to get a clue about the fault before ordering parts.

1) Go to the XP Device Manager and make sure that the card can be seen. Does it show the correct IRQ?

FWIW, unless the card supports Legacy PnP (unlikely in logic??), Windows literally knows only what the driver tells it.  If the driver were not installed, Windows probably won't automatically detect the card.  Likewise, the driver itself may not have any good way to check if its card is installed or not; hopefully it has a testing register or something that can be used to at least show that.

But in short, yeah; there's very little that can be said about ISA cards, generally speaking.  They're just kind of there, and if the CPU sends out data to certain ports, if something just happens to be listening... then it works, or if not, it's just a fart to the wind.

Frankly, I'm impressed that they support this thing so thoroughly that they actually wrote an NT kernel driver for it!

Tim

[rx8pilot]

1) Go to the XP Device Manager and make sure that the card can be seen. Does it show the correct IRQ?
2) Check for clock pulses using a scope.
3) The 74F374 and 74ACT244 chip pinouts are easy to find so follow the signal flow through, if you get an input then there should be an output.
4) Now it gets more difficult. Data on the rest of the 74 series chips can be found but you need experience in logic circuits. A 74F74 for example is a pair of flip flops so if you get inputs but no outputs it could be a faulty chip but it could also be a reset line that is stuck.
My guess is the 74F374 and 74ACT244 buffer chips.
Edit: Yes, it does look like the oscillator is the wrong way up.

It does show up in the device manager with correct IRQ. The BIOS 'forces' the OS to assign IRQ 10/11 to this card and I verified that the card is physically connected to IRQ 10 via the jumper. I also looked at the IRQ conficts and nothing else is attempting to use IRQ10.
I checked for clock pulses yesterday while the card was out on the bench and did not find anything. I had accidentally put the crystal in backward when I was fiddling with it earlier - hope that did not damage it. When I first pulled the card, it was correct. I will look a little closer to see if crystal is oscillating or not. If it is not doing anything, that would be a critical point in the investigation for sure.

It's dead, Jim.

There's no way 400mA accounts for everything on there... at least, I don't see that it could.

Is this card really so precious?  It appears to be an old fashioned 8 bit RS-422/485 UART.  Evidence: SN75179? transceivers; the big IDT parts are FIFOs, and everything else is glue logic (bus latches, address decoding, etc.).  No clue what port(s) it shows up as, but I'd be willing to bet (knowing what the FIFOs are) that it wouldn't be hard to find what addresses make them blink.  Or just DEBUG the driver program and see what it IN/OUT's to!

That was my gut feeling as well. This card is paired with a machine vision processor in a Quad IVC pick and place machine (made by ICOS). It is hard to tell what secret sauce is in there but it is definitely more than just an RS485 card. PPM had to jump through hoops to get this classic hardware to work in XP. They have since written support for Windows 7 as well. From what little I know, it is a dual channel RS485 with some sort of buffer to send patterns to the vision system. The vision system in turn does the analysis on the image and sends geometry back to the PC. I wish there was an easy way to substitute something, but all the secrets are so old they probably backed up on 5.25" floppies in someones closet.

It certainly appears to be a dumb card as far as the OS is concerned which is why the BIOS had been set to reserve the IRQ. In the end, I can get a refurb one with a guarantee for $500 so I can't spend too much time on this one. I purchased one in unknown condition that will arrive in a few days. If it works, I can do some comparison troubleshooting and maybe have a spare.

[rx8pilot]

Without too much surprise, the crystal is not doing any crystalling anymore. Not sure if that is the original problem or if it simply dies from reverse polarity.

I don't have any of the 4 pin crystals like that so I will have wait for some to be delivered. There is a surplus electronics shop down the street from me that may have something. So bummed that I bodged it like that. Silly mistake.

[pickle9000]

- Are you using the original motherboard?
- If a particular slot was used clean it and use it.
- Mark down all settings for the bios, I assume they are correct. Then re-enter them. Check the battery voltage on the mb.
- check your power supply and clocks (mb and all cards). Start a log you may need these in the future.

Do the above first

- RAM is always an issue, 7202LA50. I wouldn't even test it just install a couple sockets and install new. Cut the old ones out remove pin at a time and test the thru holes with a meter before installing a socket. The board is more valuable than the chips so treat it with care.

Even if you have to change all the chips (all the ones possible) it's only a couple hours work and will make servicing the board in the future easier (sockets). Even though I do agree with the learning approach, this is a service operation no need to get fancy. More important to get the equipment up and running so it can earn it's keep.

[T3sl4co1l]

Oh, and try another electrical test and see if the rest of the board seems okayish or not.  Hopefully no [other] chips were harmed?

Tim

[rx8pilot]

- Are you using the original motherboard?
- If a particular slot was used clean it and use it.
- Mark down all settings for the bios, I assume they are correct. Then re-enter them. Check the battery voltage on the mb.
- check your power supply and clocks (mb and all cards). Start a log you may need these in the future.

The card came out of a pre-packaged controller PC that was assembled by the company that converted the machine from DOS to XP. It does not appear to have been changed at all. I tried three ISA slots although it should not matter with that bus. I checked the PSU but the MB is a single board PC form factor so nothing is really accessible without a major effort. It is plugged into a PCI/ISA backplane.

Even if you have to change all the chips (all the ones possible) it's only a couple hours work and will make servicing the board in the future easier (sockets). Even though I do agree with the learning approach, this is a service operation no need to get fancy. More important to get the equipment up and running so it can earn it's keep.

Every single chip on the PCB except the gate arrays is <$30 including sockets for most of them,  so I added them to my DigiKey order. If I am lucky, the gate arrays are just fine and the glue logic is the culprit. I have a fantastic setup for replacing the chips with little chance of damage to PCB. My guess is that it will be less than an hour. At that point, it could only be the gate arrays or the PCB itself.

Still hoping the replacement that is on the way will work and I can put this off til I have more time. Taking multiple paths should give me a better chance of having a pick and place machine working.

Oh, and try another electrical test and see if the rest of the board seems okayish or not.  Hopefully no [other] chips were harmed?

No changes....

[pickle9000]

You can pick up an ISA POST card reader off for under 5 bucks. Pretty handy to mount a test points on. They are getting harder to find so it's a good thing to have kicking around.

The reason I mentioned the slot is procedure. Some cards have a favorite slot be that mechanical, electrical or whatever. As a general rule put things back where they where so you don't have a compounded issue.

If the betting window is open I'll take the RAM.

One handy tip for ya. You can get machine contact ic sockets without a carrier. The bare pins are just on a holder to help with install. Super handy if you lift a pad on the upper side of the board.

Good luck to ya.   

[Kjelt]

Is it a crystal or is it an active oscillator? I guess the latter.
Can't you use a signal generator then to replace the oscillator till you have a replacement?

[rx8pilot]

Is it a crystal or is it an active oscillator? I guess the latter.
Can't you use a signal generator then to replace the oscillator till you have a replacement?

It is indeed active, not just a crystal. The good news is there is an electronics shop about a mile from me so I was able to replace it this morning. I verified the crystal first, installed it, powered the card, checked for clock pulse in a few places I figured they should be. Put the card back in the PC and still cannot initialize.

This result is not surprising since it was behaving this way before I damaged the original oscillator. I will wait until Digi-Key and the other 'new' card show up. At this point, I need to be careful with the time spent. Up til now, I was getting some real benefit from the troubleshooting giving me a picture of the whole system so future issues will be easier to understand.

[rx8pilot]

Ok, an update.

replaced 20Mhz Crystal - No change
replaced the RAM LA50P chips - no change
replaced 74ACT244 - no change
replaced 74F374 chips - no change

The mail man should be delivering a 'new' card tomorrow. That will provide some reference. I am also continuing to check the PC configs to make sure I am not chasing my tail. The only thing I can report is that the PC behaves exactly the same with OR without the card installed.

Hopefully the other card will help....

[Bryan]

Is there some tantalums I see. Are they ok?

[abyrvalg]

I can try looking into the software with disassembler to check the cause of that error message if you wouldn't mind to share the sw.