WHTSCSI Missing IC

[Shift838]

I have a WHTSCSI card that I used to use on my Geneve.  I pulled it out today to test with my new ZuluSCSI I received, and I noticed the card is missing a 74LS125 for U17.  I don't recall if it was ever there, can someone verify if there is supposed to be one in U17?  I cannot seem to find a good photo on the internet.  The Manual does not list U17 at all, but there is a socket on the board for it.

 

The behavior I noticed it exhibit is that when turning on the TI, the LED on the card stays on and no title screen on the TI.  So, I'm wondering if I need to put in a LS125 there.

 

Also, mine has the daughter board on top that was added by Richard Bell.

 

 

Edited November 19, 2023 by Shift838

[+OLD CS1]

If no one beats me to it, I will pull my card this afternoon and have a look.

[RickyDean]

43 minutes ago, Shift838 said:

I have a WHTSCSI card that I used to use on my Geneve.  I pulled it out today to test with my new ZuluSCSI I received, and I noticed the card is missing a 74LS125 for U17.  I don't recall if it was ever there, can someone verify if there is supposed to be one in U17?  I cannot seem to find a good photo on the internet.  The Manual does not list U17 at all, but there is a socket on the board for it.

 

The behavior I noticed it exhibit is that when turning on the TI, the LED on the card stays on and no title screen on the TI.  So, I'm wondering if I need to put in a LS125 there.

 

Also, mine has the daughter board on top that was added by Richard Bell.

 

 

I have an original White SCSi Card U5 has an 125 in it next to the power regulator, I don't see a U17 on mine, so yours must be an updated card?

[Shift838]

Mine has Revision F on the board and a written note on the back in sharpie by Richard Bell.  States upgraded to 1.6 in July 2012.  this photo also has a 244 missing, because it's in my tester.  i'm testing all the logic ICs.

 

Edited November 19, 2023 by Shift838

[RickyDean]

11 minutes ago, Shift838 said:

Mine has Revision F on the board and a written note on the back in sharpie by Richard Bell.  States upgraded to 1.6 in July 2012.

 

Mine is a 1.5 Rev-E, used to have an prototype eprom in it. so the U designation probably don't match.

Edited November 19, 2023 by RickyDean
spelling, added content

[Shift838]

1 minute ago, RickyDean said:

Mine is a 1.5 Rev-E, used to have an protype eprom in it. so the U designation probably don't match.

I also have a U5 (LS125) right next to the voltage regulator as well, it's hidden under the fingers of the heatsink.

 

 

 

[Shift838]

I have tested all the logic chips with the exception of the U7, which is a 74LS/ALS 520.  My TL866 II Plus does not have an option to test for the LS520.

 

I do not have the schematics for the WHT SCSI card so not sure where to start looking.  Any suggestions?

 

 

 

[+InsaneMultitasker]

1 hour ago, Shift838 said:

I have a WHTSCSI card that I used to use on my Geneve.  I pulled it out today to test with my new ZuluSCSI I received, and I noticed the card is missing a 74LS125 for U17.  I don't recall if it was ever there, can someone verify if there is supposed to be one in U17?  I cannot seem to find a good photo on the internet.  The Manual does not list U17 at all, but there is a socket on the board for it.

 

The behavior I noticed it exhibit is that when turning on the TI, the LED on the card stays on and no title screen on the TI.  So, I'm wondering if I need to put in a LS125 there.

 

Also, mine has the daughter board on top that was added by Richard Bell.

 

 

My functional MDOS development system uses an updated REV F card.  It does -not- have a chip in socket U17.  All other sockets are populated.  

[+InsaneMultitasker]

The manual should be somewhere in the file labyrinth that is whtech.  It looks as if your CRU is set to >1600, is that what you expect and if so, are there any other cards at that address e.g., Horizon Ramdisk? 

 

Edit: folder with software and hardware manual

Index of /datasheets and manuals/Hardware/WHT/scsi/manuals (whtech.com)

 

[+dhe]

Here is what my Rev-E looks like:

 

 

The EPROM says 1.6, got some strange yellowing (not rust) on the fingers. To Don's credit the board is all socketed. My Serial Number is 17.

 

[RickyDean]

19 minutes ago, dhe said:

Here is what my Rev-E looks like:

 

 

The EPROM says 1.6, got some strange yellowing (not rust) on the fingers. To Don's credit the board is all socketed. My Serial Number is 17.

 

So what does the yellow board add? DMA or something? Is that something that coild be done with mine, since yours was the same revision, just not a preliminary card?

[+dhe]

Some (all?) of the WHT SCSI cards suffer from some problem (wasn't privy to what those are/were).

 

Michael Becker made the daughterboard to fix all timing problems.  They were related to newer (for the time chips) seeing a transitional phase on the base and acting upon them.

 

@Swim would know best.

[Shift838]

2 hours ago, InsaneMultitasker said:

The manual should be somewhere in the file labyrinth that is whtech.  It looks as if your CRU is set to >1600, is that what you expect and if so, are there any other cards at that address e.g., Horizon Ramdisk? 

 

Edit: folder with software and hardware manual

Index of /datasheets and manuals/Hardware/WHT/scsi/manuals (whtech.com)

 

i set it at 1600.  the only cards in the system or a flex interface, 32k, and tipi (tipi is at >1800).  I found the manuals too.  

Edited November 19, 2023 by Shift838

[Shift838]

I pulled the TIPI and 32k just be safe and just tried it with the SCSi and still the same behavior.

 

But even if I put the tipi back in then both the SCSI and TIPI LEDs stay lit upon power on and no TI title screen.

Edited November 19, 2023 by Shift838

[RickyDean]

@Shift838,  I would buy a new 520 and replace it, may be shorted internally, or something. Then I would suspect the Pal chips next. But I don't know what's under the yellow board. The Scsi IC could also have an issue, and if the tipi works fine when the Scsi card is pulled, then I would probably rule the Tipi out as a suspect, and just look at the chips mentioned on the Scsi. I don't have a clue as to whether the PAL can be replaced at this point, don't know if it's been mapped out, but @Swim of course should have that info.

 

[Shift838]

started testing voltages.  the 2x 7805 are putting out the 5.1v with no issue it seems, but multiple ICs on the board when testing are only getting under 4.75 volts, which is the minimum voltage required to operate. 

 

The Only IC's that are getting at least 4.75 to 4.9 volts is the SRAM, EPROM, GAL16V8 and the LS245, all the rest or getting under the minimum voltage requirements.

 

So, I'm wondering if I need to go ahead and replace the voltage regulators or even the capacitors.

 

Thoughts?

 

 

Edited November 20, 2023 by Shift838

[RickyDean]

1 hour ago, Shift838 said:

started testing voltages.  the 2x 7805 are putting out the 5.1v with no issue it seems, but multiple ICs on the board when testing are only getting under 4.75 volts, which is the minimum voltage required to operate. 

 

The Only IC's that are getting at least 4.75 to 4.9 volts is the SRAM, EPROM, GAL16V8 and the LS245, all the rest or getting under the minimum voltage requirements.

 

So, I'm wondering if I need to go ahead and replace the voltage regulators or even the capacitors.

 

Thoughts?

 

 

It's reasonably cheap to change out the caps. especially the tantalums and the electrolytic cap. mine doesn't have that one. I don't think the filter caps matter two much here. I'd say the regs are fine, but if you want to reduce heat, you can go the route you took on the Ide card. The card is definitely worth the effort.  

[+InsaneMultitasker]

@Shift838 - Some troubleshooting thoughts:

 

Have you tried the SCSI card without any devices connected to it?   The old 5.x SCSI2SD devices passed an interrupt back to the SCSI card under certain conditions.  Rule out whether a device is causing an incessant or unserviceable interrupt. 

 

Have you tried a different flex cable?

 

Turn off the PEB, turn on the console. Is it locked?  If not, turn on the PEB. Is it locked?  If not, use mini memory debugger to turn on the card and inspect the EPROM.  I forget the exact syntax but something like

C1600

1   (should turn on light)

M4000  (should see >AA)

 

You can remove the LS245 and/or LS244s to get a sense of whether the card is causing issues on the data or address bus. Sometimes, a chip will pass the test but not work on the bus.  RElated to the first item, I've seen RS232 cards that hold the address and/or interrupt line via a flakey or zapped LS244.

 

Any idea why the card failed?  Was it accidentally pulled out of a live PEB or did it die unceremoniously?  

 

[Shift838]

1 hour ago, InsaneMultitasker said:

@Shift838 - Some troubleshooting thoughts:

 

Have you tried the SCSI card without any devices connected to it?   The old 5.x SCSI2SD devices passed an interrupt back to the SCSI card under certain conditions.  Rule out whether a device is causing an incessant or unserviceable interrupt. 

 

Have you tried a different flex cable?

 

Turn off the PEB, turn on the console. Is it locked?  If not, turn on the PEB. Is it locked?  If not, use mini memory debugger to turn on the card and inspect the EPROM.  I forget the exact syntax but something like

C1600

1   (should turn on light)

M4000  (should see >AA)

 

You can remove the LS245 and/or LS244s to get a sense of whether the card is causing issues on the data or address bus. Sometimes, a chip will pass the test but not work on the bus.  RElated to the first item, I've seen RS232 cards that hold the address and/or interrupt line via a flakey or zapped LS244.

 

Any idea why the card failed?  Was it accidentally pulled out of a live PEB or did it die unceremoniously?  

 

Console is not locked up without the PEB powered up.  I'll try a different flex tomorrow.  I did replace the LS244s and LS245 but same result.  i'll work on it some more tomorrow and try the mini memory debugger.

[Shift838]

9 hours ago, InsaneMultitasker said:

@Shift838 - Some troubleshooting thoughts:

 

Have you tried the SCSI card without any devices connected to it?   The old 5.x SCSI2SD devices passed an interrupt back to the SCSI card under certain conditions.  Rule out whether a device is causing an incessant or unserviceable interrupt. 

 

Have you tried a different flex cable?

 

Turn off the PEB, turn on the console. Is it locked?  If not, turn on the PEB. Is it locked?  If not, use mini memory debugger to turn on the card and inspect the EPROM.  I forget the exact syntax but something like

C1600

1   (should turn on light)

M4000  (should see >AA)

 

You can remove the LS245 and/or LS244s to get a sense of whether the card is causing issues on the data or address bus. Sometimes, a chip will pass the test but not work on the bus.  RElated to the first item, I've seen RS232 cards that hold the address and/or interrupt line via a flakey or zapped LS244.

 

Any idea why the card failed?  Was it accidentally pulled out of a live PEB or did it die unceremoniously?  

 

The console will freeze when turning on the console first then the PEB, so I cannot test the MM Debug process.

 

No idea why the card failed, it has been in my closet since I got my HFDC back from you and it was not pulled out while the power was on.  It was working fine with the SCSI2SD.  Even with no SCSI devices connected to the card the behavior is the same.  

 

is there a schematic for this thing somewhere, I could not locate one on the FTP.  

 

I have ordered a new 74ALS520 as well.  Once that gets here, I'll try swapping chip by chip to see if a chip is flaky.  

[RickyDean]

As far as I know, there was never a schematic released into the wild for the card. I've been thinking of mapping mine out and trying to build another on a Fetzner or Bunyan board. I have a coupe of NCR 5380 Scsi Ic's.

[+OLD CS1]

How often does the SCSI chip itself fail?  Do you still want to see my card?

[Shift838]

I replaced the 74ALS520N IC and still the same issue.  I also attempted to replace the SRAM with no luck.

 

So now i'm down to either the daughter board that has an issue or the SCSI controller IC.

[Shift838]

Swapped the termination resistor packs as well as the SCSI Controller IC and replaced the 7805's but still no luck.

 

I have extras of all other chips so I will try swapping one at a time.  If that does not work, then the only thing it can be is the daughter board that Richard B. installed.

 

 

[RickyDean]

27 minutes ago, Shift838 said:

Swapped the termination resistor packs as well as the SCSI Controller IC and replaced the 7805's but still no luck.

 

I have extras of all other chips so I will try swapping one at a time.  If that does not work, then the only thing it can be is the daughter board that Richard B. installed.

 

 

You have replacement PAL'S, with the right programming? PAL's can go too, you have that one next to the small switch, just sayin, don't rule it out.