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GRiD 1530 Becomes unresponsive after idling for 30 seconds?

well, doing in and out to keyboard controller from dos debug WHILE actually typing on the keyboard will not end well. use debug.com to write simple .com program or try afd.com (advanced full screen debugger, my dos favorite) to do that. or write simple nasm program. also, try qa plus or checkit, they do have keyboard controller tests.
now, i dont think this is keyboard controller problem.
refresh.com refreshes memory by reading it on cpu. which could point to a problem with chipset, and the memory refresh. the refresh tsr does cpu based refresh of dos memory, but it doesnt touch anything over 640kb. the system may be more stable with it without himem.sys
as for keyboard controller, it also controls a20 line gate which is used by himem.sys
also, have you tried grid diagnostic tools? see diagrom.zip
 

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0xDEADBEEF said:
well, doing in and out to keyboard controller from dos debug WHILE actually typing on the keyboard will not end well. use debug.com to write simple .com program or try afd.com (advanced full screen debugger, my dos favorite) to do that. or write simple nasm program. also, try qa plus or checkit, they do have keyboard controller tests.
now, i dont think this is keyboard controller problem.
refresh.com refreshes memory by reading it on cpu. which could point to a problem with chipset, and the memory refresh. the refresh tsr does cpu based refresh of dos memory, but it doesnt touch anything over 640kb. the system may be more stable with it without himem.sys
as for keyboard controller, it also controls a20 line gate which is used by himem.sys
also, have you tried grid diagnostic tools? see diagrom.zip
Click to expand...
Thanks again for the suggestions. Somehow I don't believe those GRID diagnostic tools have come up in any of the threads I've made about this computer, so I will try those first.

I'm pretty sure I have run all the tests in checkit and found nothing wrong.

I will admit, I am not a programmer so writing even a simple program to do stuff like this isn't something I have any experience with (I don't even know what a nasm program is). I can muddle through with batch files but even as those those get a bit more complex I need to copy and paste from somewhere. I also don't really have any experience using debug or looking at anything that looks like AFD.

I will gladly desolder and replace parts though if we can figure out what exactly isn't working. That is more my speed. lol

Regarding himem.sys, I have had that disabled for all of the testing I've done today with no TSRs or devices loaded. It seems likely that himem.sys is responsible for the change in behavior a saw (from hard locking system to just losing kb input and getting beeps) after disabling all of the stuff in config.sys an autoexec.bat.
 
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@Ozzuneoj nasm (or NASM) is the name of the executable (technically 'nasm.exe') for the Netwide Assembler which takes a program in x86 assembly language and produces a binary executable.

NASM

The Netwide Assembler (NASM) is an assembler and disassembler for the Intel x86 architecture, used by developers worldwide
www.nasm.us

debug.com is a part of MS-DOS and is a "line-oriented debugger".

Essentially it's a simple "shell" that takes a specific set of commands and parameters that are useful in debugging.

If you've ever used a machine code monitor on a 8-bit computer, it provides similar functionality.

You can use commands to directly read and write memory (including filling a block of memory), examine the contents of cpu registers, perform basic input/output, assemble a program, dissassemble a program, execute a program (go), etc.

en.wikipedia.org

Debug (command) - Wikipedia

en.wikipedia.org en.wikipedia.org
 
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Small update. I ran everything relevant from the GRiD Diagnostic tool package. The extended memory test and 640K test where both good. Interestingly, the 640K test actually unloads the system from RAM so it needs to be shut off with the power switch.
20260518_025143 (Custom).jpg20260518_152706 (Custom).jpg

The only odd result I had was the clock test. When I ran that it seemed like it was going okay, then the system starts doing this obnoxious two tone beeping and presents this message:
20260518_152822 (Custom).jpg
The message alternates with one that says to press F10 to monitor. I pressed F10 and got this:
20260518_152853 (Custom).jpg
And the system was unresponsive at that point (beeping keyboard).

Upon reboot, I get a message saying that the clock's timer is not started or the clock is not set after POST but before DOS loads. To get this to stop showing at boot I have to use the time command in DOS to set the time, then the message goes away until I run the clock test again.

I wonder if there is something wrong with the NVRAM in the Dallas chip? I have some more on hand I can try swapping out, though they are the exact same model. Could this cause any of the issues I've been having? It could just be that this test is super sensitive. The clock that is in there now keeps time just fine, it will just be off a tiny bit over time. It was off by, I think one minute after sitting for 5 years.

eswan said:
Try disconnecting internal keyboard and use just an external?

Mine is back to throwing KBC and Gate A20 errors on boot.
Click to expand...
Good thought, but I disconnected the internal keyboard completely when I was testing the external. I also tried with both connected and there was no difference (though it is interesting that they can be used simultaneously).

Sorry to hear you're having errors. I have not had any errors like that come up on this machine yet.

Istarian said:
@Ozzuneoj nasm (or NASM) is the name of the executable (technically 'nasm.exe') for the Netwide Assembler which takes a program in x86 assembly language and produces a binary executable.

NASM

The Netwide Assembler (NASM) is an assembler and disassembler for the Intel x86 architecture, used by developers worldwide
www.nasm.us

debug.com is a part of MS-DOS and is a "line-oriented debugger".
Click to expand...
Thanks for the explanation. I had never used or heard of NASM.

I have used the debug command a couple times over the years (it was mentioned in my previous post before the one you quoted) and I know what it is, I just don't have any knowledge built up that would allow me to just start typing debug commands without copying them from somewhere.
 
It looks like mine throws the KBC and Gate A20 errors if it's been off for a long period. If I leave it on for around 20-30 minutes at the error, a warm or cold boot will succeed with a 'Time of Day Clock Stopped'. I replaced the battery just last week. Hitting enter at the time/date prompt (no autoexec) sets it fine and no errors on reboot.It seems to have the same or similar problem as yours- sit idle at a dos prompt and after 30 seconds or so pressing any key will make it unresponsive. DIAGROM's RAMTEST, EXTENDED, and CLOCKTST all ran fine. CheckIt's system board and memory test pass. It's video test goes though several screens before hitting one that blanks the screen and doesn't return, requiring a power cycle. Interestingly, checkit's benchmark shows it as running at 12.5mhz.

The hardware ref manual does mention a hard drive spindown timer that is only supposed to be automatically enabled for the smaller hard drives. The larger one apparently used too much power on re-spinup that it was counter productive for power savings.
 
eswan said:
It looks like mine throws the KBC and Gate A20 errors if it's been off for a long period. If I leave it on for around 20-30 minutes at the error, a warm or cold boot will succeed with a 'Time of Day Clock Stopped'. I replaced the battery just last week. Hitting enter at the time/date prompt (no autoexec) sets it fine and no errors on reboot.It seems to have the same or similar problem as yours- sit idle at a dos prompt and after 30 seconds or so pressing any key will make it unresponsive. DIAGROM's RAMTEST, EXTENDED, and CLOCKTST all ran fine. CheckIt's system board and memory test pass. It's video test goes though several screens before hitting one that blanks the screen and doesn't return, requiring a power cycle. Interestingly, checkit's benchmark shows it as running at 12.5mhz.

The hardware ref manual does mention a hard drive spindown timer that is only supposed to be automatically enabled for the smaller hard drives. The larger one apparently used too much power on re-spinup that it was counter productive for power savings.
Click to expand...
That is interesting about the hard drive spindown timer. I haven't looked at this reference manual myself. Does it say whether this is part of the drive itself or a BIOS feature? I am using a CF card on an IDE adapter with a modded BIOS currently. I'm thinking that when I get some time I should put the old BIOS and hard drive back in to see if any of this behavior changes now that I have way way more information about what is actually happening and that there may be two different problems (one time related, one not, but both input related).

And it's funny you mention that about the CPU showing as 12.5Mhz! I noticed when I was looking things over yesterday that the clock crystal is only 25Mhz, so, I believe the CPU can only run at 12.5Mhz. I wonder if anyone has tried swapping this with a 32Mhz crystal to get the CPU running at full speed? Probably not a great idea to stress one of these unnecessarily given the rarity of the chipset components and the lack of ventilation, but it does make me wonder.

I see that the 1530 EXP is said to have a 12.5Mhz CPU and the 1530 is 16Mhz, so I just assumed that mine was running at the full speed marked on the CPU:
Since you and I both have 12.5Mhz models, there were apparently some 1530s configured to run at the lower speed of the EXP.

Maybe that means it's as simple as dropping in a different crystal and it works fine? They may have just used identical systems aside from the crystal so they could more easily charge extra for the 16Mhz model, or I guess it could have been done to extend battery life somewhat.
 
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i would be careful with overclocking like that. i doubt the faraday chipset is rated for higher speeds. it was mostly at chipset and i think using it for 386 may be an ungodly hack.
i saw the clock stopped after aborting rtc test in diags as well. same happens when you replace cmos battery.
not sure about hdd spindown, i dont see anything about it in gridcase 1520 bios disassembly on github, so if there ever was anything like that i would expect it to be an optional tsr.
 
0xDEADBEEF said:
i would be careful with overclocking like that. i doubt the faraday chipset is rated for higher speeds. it was mostly at chipset and i think using it for 386 may be an ungodly hack.
i saw the clock stopped after aborting rtc test in diags as well. same happens when you replace cmos battery.
not sure about hdd spindown, i dont see anything about it in gridcase 1520 bios disassembly on github, so if there ever was anything like that i would expect it to be an optional tsr.
Click to expand...
Of course, I am not planning to attempt anything like that without some confirmation that it could work and it would certainly come after I have the system stable again.

I only mentioned it because some sites state that the 1530 has a 16Mhz CPU and the EXP has a 12.5Mhz CPU. If all the systems ran the same chipset and just had different clock crystals that would be one thing... but I am now leaning toward this being a mistake on sites like classicbits.net . The actual Grid 1530 technical manual states that the 1530 has a 386 running at 12.5Mhz.

Even 1530 boards with completely different layouts, such as the one posted here, have 16Mhz CPUs but only 25Mhz (12.5Mhz) crystals.

So, yeah, I have no intention of overclocking this thing if none of them ever ran higher than 12.5Mhz.

Also, what is with the totally different board design at that link above? Mine has some really funky looking bodge wires and things on it that make it looks a bit less refined.
 
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Mine is simillar to the one in the ram error link alongside the 1520. Socketed Faraday chips, no dallas clock, battery under the hinge. Later 386 with Intel logo 16mhz and double sigma. Has a third connector by the ide/floppy connectors (JVC drive interface?) Bodge wires all over, and a piggybacked chip or two. I'll check to see if I can find any revision markings and survey the chip dates.

Tried transfering files over serial with Procomm Plus to a linux shell. With refresh.com loaded, too many dropouts. Without, it transfers without error but the system becomes unresponsive on write to the hard drive.

-edit-
Quick check shows 48th week of '89. Don't see any revision marking.
Also, pressing any key during a zmodem transfer instantly pops up a CRC_ERROR.
 
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Good news/Bad news.

Good news:
My 1530 seems to be running fine now. Boot up, sit at a command prompt, edit config.sys and himem.sys to my hearts content, transfer files over serial. No problems.

Bad news:
I swapped out the 1 meg replacement sipps for the original 256k sipps. Originals are 8 256kx1 NEC 120ns chips, Replacement were 2 1mx4 Toshiba 80ns. Maybe adding/removing cleaned up some corrosion fixing my original problem.
 
eswan said:
Good news/Bad news.

Good news:
My 1530 seems to be running fine now. Boot up, sit at a command prompt, edit config.sys and himem.sys to my hearts content, transfer files over serial. No problems.

Bad news:
I swapped out the 1 meg replacement sipps for the original 256k sipps. Originals are 8 256kx1 NEC 120ns chips, Replacement were 2 1mx4 Toshiba 80ns.
Click to expand...
Interesting. The problems your 1530 was having were slightly different from mine, but definitely similar. So, this is yet another data point. I will see what I can do here.

eswan said:
Maybe adding/removing cleaned up some corrosion fixing my original problem.
Click to expand...
Sorry if this is a dumb question, but can't you just put the other ones back in to find out if this was just from adding and removing them? That seems like a pretty significant factor considering how hard\expensive it is to obtain RAM for these.

Maybe it is some kind of RAM chip incompatibility that only surfaces in specific situations. The chips I swapped onto the SIPPs I'm using are 1mx4 Toshiba 70ns, so they are probably quite similar to yours. The ones that were on the SIPPs originally were 256kx4 Fujitsu 100ns.

20260520_113443.jpg

If there was room to add sockets to these SIPPs that would be amazing. Sure would look funny though... lol

I am looking around for some datasheets now to compare them. If you can post pictures of the RAM you are using (working ones and non working ones) and any datasheets that match them that would be very helpful.

Some of the datasheets from the 80s are not as comprehensive as others, so its not easy to figure out if there are any significant differences here.

Here are some that I have found so far. I had to settle for slightly different latency ones on the more detailed sheet, but I found these for the Toshiba TC514400ASJ-70 chips I added:

https://www.datasheets360.com/pdf/-2000581759250007785
https://www.alldatasheet.com/datasheet-pdf/view/31680/TOSHIBA/TC514400ASJ-60.html

And this for the Fujitsu 81C4256 chips I replaced:
https://www.datasheetarchive.com/datasheet/MB81C4256-10?term=mb81c4256&id=df55001010557fdf

These ones may be different since they have an A at the end, but it's worth posting anyway:
https://www.westfloridacomponents.com/mm5/graphics/H05/MB81C4256A-70PSZ.pdf
 
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When I added 2mb to my 1520 I used SIPP's from an AT clone but used a saw to cut the ears off so it would fit.
The board is too tightly packed and there's not enough height I found to install slots.
 
@Ozzuneoj bitsavers.org has a lot of old databooks/datasheets, you might look there if you need more detail.

I think people often use the word 'datasheet' interchangeably for short product briefs and the longer form that often includes more detailed information included signal timing and graphs of expected waveforms.
 

TC514400J/Z-80
TC514400J/Z-10

A-271 (pdf pg. 306/730)

1Mx4 is also called 4M where M stands for Megabit.

The line in the table of contents/parts list suggested the datasheet was originally issue in October 1989 (10-89).

-----

Also,


MB81C4256-70/-80/-10/-12

pg. 382/618 (PDF), 2-187 (document page numbering)

The MB81C4256A is in there too, as are the ones ending in L (low power?).

EDIT

Evidently J, Z refer to the package type where J means SOJ and Z means ZIP.

I suspect the A just signifies a different speed class, not unlike the Z80A and Z80B having different maximum clock speeds.
 
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Ozzuneoj said:
Also, what is with the totally different board design at that link above? Mine has some really funky looking bodge wires and things on it that make it looks a bit less refined.
Click to expand...
I have gridcases with two board designs for 1530, one with chips laid out horizontally, the other verticall. I think there are also two 1520 designs too?
 
interesting, toshiba again? is there some weird timing issue on toshiba or something?
 
Swapping back to the Toshiba 1meg simms, back to the same freezing up problems. I remember a similar issue with 8-bit trs80s, some manufacturer's refresh timing requirements were double others. Was just about ready to use this for testing--
1779318203965.png
but I think the pins are a poor fit.
 
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