GRiD 1530 stopped POSTing...

[Ozzuneoj]

I have done a bunch of work on this 1530 over the last five years or so. In the removable power supply I have replaced a blown tantalum, the Rifa caps and a very leaky Nichicon PC series cap.

A couple weeks ago, after replacing that bad Nichicon and installing an Intel 387 16Mhz co-processor, I decided to give it some more upgrades. So, I upgraded it from 1MB to 4MB by just replacing the 8 chips on the existing SIPPs (since I had no SIMMs that were small enough to fit in such a cramped space after adding pins). Didn't take long at all and worked perfectly!

Next on my list was using ROMbuster to patch a BIOS to allow it to use a 512MB CF card. I was able to get the system to turn on with the patched BIOS and the original 20MB Conner drive installed, but it gave an error and would not find the hard drive anymore. I tried wiping the BIOS chips and using ROMbuster with different settings but nothing would fix the detection of the original HDD without just putting the original BIOS chips back in. At this point the hard drive and floppy were still installed and I had not removed them or any of the screws that hold them (or the power supply board that is in the back).

So, after disassembling it further to see what I needed to connect a CF card to the backplane, I put the project on hold for about a week. Today I finally put together an IDE gender changer so I could hook up a cable from the GRiD backplane to an IDE to CF card converter. I double-triple-quadruple checked the pinouts and orientation of everything to be sure I didn't get anything wrong, so I am 100% positive that the pins were all in the correct places.

However, when I tried to power on the system with things partially assembled, the lights just flickered a little, I would get a very slight pop from the internal speaker and nothing else would happen. I tried this a few more times and I tried without anything connected to the IDE cable and it made no difference, so it wasn't a short in the adapter.

I was kind of desperately trying things at this point, so I can't remember exactly the order of things, but eventually I was able to get more life from the system (seemed like installing the two power supply board screws did it? Hard to say...). Sadly, it would still not post, even though the hard drive would spin up and the green LED (second from the top) stayed on. During all of this I never heard anything from the floppy drive (tried with it and without it connected), and there is no beep or anything on the display, so I am assuming it isn't POSTing.

And that is where I am now... The power will come on, and if the backplane cables are properly connected the green LED (2nd down) is steady but I get nothing else from the system. I am leaning toward the possibility of a ground issue when I tried powering it on before partially assembled and it would not work. Maybe the system really needs one or both screws installed on the power board at the back? I notice that disconnecting the backplane cables entirely seems to cause the same situation where I get a slight blip of LEDs (with slight click from speaker), which is odd. I'm positive it was connected before.

Regardless... the system is powering on with a CF card or the original HDD but will not POST, no matter what. I am at a loss as to what could be causing this. I have tried it with the new and the original BIOS ROMs (and I have the even\odd in the correct sockets). I have also tried pulling the BIOS chips out of the system completely and it does exactly the same thing. So, it is not getting far into the power-on process at all.

If anyone has any suggestions as to what may have happened or what I should check, please let me know. Sorry if this is a bit rambly. If you have any questions, just ask.

 

[Conventional Memories]

seeing as this changed with screwing it back down, it almost sounds like a grounding issue. maybe check if the grounds all make a good connection. PSU, case, and motherboard.
The short speaker pop and lights, could suggest maybe the psu is turning off. check if all voltage rails are stable?

 

[Ozzuneoj]

seeing as this changed with screwing it back down, it almost sounds like a grounding issue. maybe check if the grounds all make a good connection. PSU, case, and motherboard.
The short speaker pop and lights, could suggest maybe the psu is turning off. check if all voltage rails are stable?

Thanks for the suggestions.

I have made some progress!

I noticed that if I have a hard drive connected via a 40pin IDE cable through the IDE "gender changer" I put together (so I could attach a cable to it), the drive spins up, the Lower Drive light is solid green but the system does not POST. With the CF card + adapter connected (via a 40pin+power to 44pin adapter) the Lower Drive light is also green and the CF adapter's activity light is also solid red (still no POST). If I disconnect the CF card and adapter and just leave the 40pin IDE+ power to 44pin adapter (which the CF adapter connects to), the Lower Drive light is still green! This tells me it is seeing some kind of activity without a drive even being connected. So, it seems to be a cabling issue?

If I completely remove the gender changer and connect the hard drive directly to the backplane, it turns right on and POSTs no problem... display, memory count, etc. all working. That's great! But very confusing. I don't see how having pins connected to the IDE connector with none of them touching anything could cause the system to not boot. I made sure that everything is in the right orientation, pin 1 was in the right place on the cable\drive, etc. It is very strange. The only thing I can think is that the pins aren't quite long enough and are causing some odd resistance issue within the connector... or maybe I picked the ONE pristine looking short 40pin IDE cable I own that is internally shorted somehow? lol

What made it more confusing is that if there is absolutely no HDD\CF card connected, the system does not POST and there is no display. Maybe there is some kind of minimum power draw required for the power supply to work, or there is a weak component in the power supply that is making it behave this way? Not a huge deal since I obviously intend to have a drive connected, but it is odd.

I will keep tinkering with my gender-changer\cable situation (since I need to be able to use a cable to connect a CF adapter since the power + IDE do not line up perfectly with the backplane), but in the meantime if you have any thoughts about why the system would not post without a hard drive connected, maybe there is another issue I can catch before it becomes a bigger problem.

I'm soooo glad that it is booting again. I was so worried that some fluke thing happened and that some mystery component on the motherboard or in the display had died. Whew!

Thanks again!

EDIT: I just tried it with all of the pins pulled out of my DIY gender changer and stuck directly into the proper places on the end of the IDE cable so that it can connect to the backplane and it still does the solid green LED thing (no POST or display) with either the hard drive or the CF adapter connected to the cable. It must be a bad IDE cable? It is a 40pin cable with both master and slave connectors, but it is very short so I don't think this should make any difference. I have tried connecting drives to either the slave or the master connector and it makes no difference. I guess I'll try a different cable when I get some more time. It takes a while to move all of those pins...

 

[Ozzuneoj]

Okay, I bought some longer pin headers to make sure that it wasn't a problem with the pins being too short. I got them today and installed two rows of 20 pins into the IDE connector on the GRiD backplane, connected an IDE cable to it, connected the original hard drive to it aaannnd... nothing. It still doesn't work. The drive spins up but the "upper drive" LED is solid green and the system won't post. I also swapped the cable out for a completely different one (an 80 conductor one, just because) and it made no difference. Plugging the hard drive directly into the backplane works fine.

What are people using to upgrade the storage on a GRiD laptop? It seems my system does not work with a cable attached... for some reason. If the new drive\adapter cannot slot directly into the backplane where the original Connor drive was I don't know how it could work without a cable.

This just seems so strange. The Connor hard drive and backplane use a standard IDE pinout and orientation, correct? The PCB markings on the bottom of the drive seem to indicate Pin-1 being on the side facing the power connector, as expected.

EDIT: I have an observation that is unrelated to this problem, but still interesting. I was thinking I should replace the caps on the floppy drive because people say that often needs done... though I have not had any problems with this drive. Mine has five yellow ELNA through-hole capacitors soldered onto surface mount pads on the bottom. Some are CE-BP bipolar caps, the rest I can't tell what series because they are glued down, but all look similar.

Anyway, I have a basic LCR meter and I used it to check the caps and to my surprise these have lower ESR than all of my modern cheap caps of the same rating by a long shot (~6ohms on new Panasonic GA caps, ~2ohms on the 35 year old ELNAs; measured using series resistance mode at 100khz with one leg desoldered), the capacitance is almost dead on and the dissipation factor looks normal as well. I imagine that some new low-ESR 4.7uf caps would have specs that are a bit closer, but I don't have any at the moment even though I have thousands of new caps on hand.

They aren't leaky, and the drive works fine (when the system is booting properly, of course). So... I guess these are still okay? It feels like replacing them with new caps just to triple the ESR would, at best, do nothing, and at worst cause problems with the drive's operation or longevity.

 

[Ozzuneoj]

I guess I have lost the ability to edit my previous post already.

Anyway, I meant to specify that the floppy drive mentioned above is an Epson SMD-240.

 

[Ozzuneoj]

UHG... Okay. Now I feel stupid.

The problem is that IDE cable rows (top\bottom) will be inverted if you try to connect them straight through. They don't just extend the pins straight out. So, pin1 is the top left pin on one end, but pin1 will be the bottom left pin on the other end. That is just how the cables are made. I used my multimeter to test it just now and sure enough, top row on the "pin1" side connects to the bottom row on "pin1" side at the other end of the cable.

A motherboard connecting to a drive is built to account for this, but if you were to daisy chain IDE cables using a simple straight-through gender changer you'd be flipping the top row to the bottom. This is exactly what I was trying to do by using pin headers as gender changers. DOH!

So, yeah, after that whole debacle I'm glad nothing was damaged (at least nothing seems to be). Throughout 27 years of being very hands-on with the insides of computers, the flipping of the rows from one end of an IDE cable to the other has never once come up.

It seems obvious now though. They use the same connector on both ends of the cable when they manufacture them, so with the staggered layout of the pins in the connector it will inevitably be mirrored on the other end.

If I had known this a couple weeks ago I could have saved myself tons of time and headaches trying to make something myself and just ordered some IDE extension cables like these:

https://www.amazon.com/IDE-Extension-Cable-Male-Female/dp/B075D6CQLQ

Amazon.com: cunueae IDE 40-pin Male-to-Female Hard Drive Extension Cable, 3.71-inch Flat Ribbon Cable, for 3.5-inch PATA Hard Drive Adapter Connector Expansion Splitter Card Module Board Bracket Socket Panel : Electronics

Amazon.com: cunueae IDE 40-pin Male-to-Female Hard Drive Extension Cable, 3.71-inch Flat Ribbon Cable, for 3.5-inch PATA Hard Drive Adapter Connector Expansion Splitter Card Module Board Bracket Socket Panel : Electronics

www.amazon.com

... which is what I'm going to do now. This is, I believe, the last thing I need in order to finish upgrading this system. I can't wait to have a 512MB CF card in it. Being nearly silent and being significantly faster should just make it seem all the more like a piece of space-age tech.

 

[Ozzuneoj]

Boy this has been a struggle... but I finally got the proper IDE extension cables after Amazon lost the first shipment.

Thankfully, that seems to work. The original hard drive will boot from the IDE extension using the original BIOS ROMs.

The BIOS modded with ROMBuster has been giving me a lot of trouble though. I followed the instructions in the .byt file carefully and I have done it several times.

Sadly, I got ahead of myself and filled my CF card with stuff (from my main PC) before finding out that it wasn't quite working right. It took a couple hours. Very stupid mistake...

Eventually I realized that there was a discrepancy in the drive geometry of the 512MB CF cards I have on hand vs the geometries that ROMBuster was adding (had to hook the CF card up to another old PC to verify the Normal\non-LBA geometry via disk drive auto-detection). Once I added the other Geometry in ROMBuster and flashed those ROMs, it seemed like the system was at least aware that the drive was there but it wouldn't boot from it.

(FYI, the geometry of the drive was: 983 cyls, 16 heads, 63 sectors = 507MB)

In the process of trying to correct the situation I managed to corrupt the drive and lose all of the time\work I put into copying files and programs to it. Nice.

Now, I am able to boot from a floppy and fdisk+format a 512MB CF card, but the system tends to just stop responding when trying to do much writing to the drive (sys c: , for example), and it simply will not boot from it. I have tried two 512MB CF cards of the same type. They are 512MB X-431"Launch" CF cards I got in a bulk lot a few years ago. They read\write perfectly fine on my main PC with a USB reader so it is definitely an issue with the GRiD 1530 and\or the BIOS.

Strangely, a known-working Pretec CFL032 32MB CF card I was using for testing prevents the system from POSTing at all, while the 512MB cards at least allow the system to POST and can even be partitioned and formatted. Very weird.

At this point I am so fed up with having this thing dismantled laying all over my work bench for like a month... I just wanted to upgrade the storage. -_-

 

[Istarian]

For what it's worth, you could still have a power supply fault of some kind which is causing system instability.

Voltage (electrical potential) is always measured with respect to some other part of the circuit.

So a measurement of +5V can be obtained when comparing +5V to 0V ("ground") or +15V to +10V. The observed difference in electrical potential would be +5V in either situation.

-----

Just a thought, but you could try measuring the cable/wires with a multimeter in resistance mode (unit is ohms, typically signified by the greek letter omega).

If they aren't made of pure copper they will almost certainly have a higher resistance...

Wire Resistance Calculator

The wire resistance calculator determines the resistance and conductance of a wire.

www.omnicalculator.com

^ here's a calculator that can tell you the expected resistance of a piece of wire based on material, length, and diameter -- IDK how this differs between solid core and stranded wire though

 

[Ozzuneoj]

For what it's worth, you could still have a power supply fault of some kind which is causing system instability.

Voltage (electrical potential) is always measured with respect to some other part of the circuit.

So a measurement of +5V can be obtained when comparing +5V to 0V ("ground") or +15V to +10V. The observed difference in electrical potential would be +5V in either situation.

-----

Just a thought, but you could try measuring the cable/wires with a multimeter in resistance mode (unit is ohms, typically signified by the greek letter omega).

If they aren't made of pure copper they will almost certainly have a higher resistance...

Wire Resistance Calculator

The wire resistance calculator determines the resistance and conductance of a wire.

www.omnicalculator.com

^ here's a calculator that can tell you the expected resistance of a piece of wire based on material, length, and diameter -- IDK how this differs between solid core and stranded wire though

Thanks for the input.

I just checked the voltages at the IDE power connector and 5v is measuring at 5.08v, and 12v is measuring at 12.35v, so those are both within spec.

I'm not sure exactly what you mean with regard to measuring the resistance of cables and wires though. Do you mean to measure the resistance of the IDE extension cable I just received? It is worth noting that the system seems to be perfectly stable and works fine with the original 20MB hard drive and original BIOS ROMs installed. I played Elite on it for a while multiple times and ran some other tests with no issues.

The issues seem to arise when trying to use a CF card along with the modded BIOS that is meant to prevent the system from being unstable with CF cards installed.

I have tried different card adapters and different cards and they all exhibit issues. I just found a 128MB Sandisk that had some DOS programs on it (DOSBench, NSSI, checkit, Volkov Commander, etc.). I had to boot from a floppy to access the hard drive (it has no OS on it), but then I ran VC and it opened the program but when I tried to interact with it the system stopped responding and then rebooted itself (no idea if this is an issue with the CF card, BIOS or just VC). After a reboot I tried running DOSBench from the CF card and it said "file not found" and then froze up.

Maybe I have run into some kind of compatibility issue with the BIOS mods.

 

[Ozzuneoj]

Well, it seems that I am experiencing some other issues. Without getting into too much detail:

I ran memtest to be sure the memory I installed was okay and the test passed with zero errors.

I just stumbled upon this thread:
https://forum.vcfed.org/index.php?threads/grid-1520-startech-cf-card-reader-and-transcend-512meg-cf-card-not-recognized.1250406/

And I noticed that the OP was able to fix a similar boot issue with a CF card by running fdisk /mbr. I did this, then did sys c:, rebooted and to my astonishment it actually booted from the 512MB CF card!

... but as soon as I tried to copy files from the floppy to the CF card it would start to do it and then give a "file not found" error, and the system would just hang with the cursor blinking and no prompt to type at.

I then switched BACK to the hard drive (and original BIOS, since the modded BIOS does not detect the original hard drive), tried to do the same things and it seemed like it was working at first, but then it stopped responding during a transfer from the floppy to the hard drive AGAIN.

So, I seem to have some other issues going on. I will try to rule out the floppy drive next... maybe by just trying to copy a bunch of files from one folder to another on the CF card with the floppy disconnected entirely.

One other thing happened that would be funny if it wasn't so sad. The first time I successfully booted from the CF card to DOS 6.22 the system asked for me to input the time and date. When I hit enter to leave the current date the system speaker let out this 1-2 second long descending fart noise and then froze up with the cursor blinking but no longer responding. I have no idea what that was.

And to think I thought I'd just be throwing a CF card and a couple of modded BIOS ROMs into this thing and closing it up for good a MONTH ago. Oh how wrong I was...

 

[Istarian]

I suppose if your system is corrupting the data on the CF card during boot that would explain why fdisk /mbr and sys c: fixed the problem, at least temporarily.

Do you use the same cabling regardless of whether you have the original hard disk of CF adapter/card hooked up?

Faulty cables or a loose/poor connection can cause a system to simply not detect the presence of an IDE drive. Data that is read/written is communicated in parallel, so any problems with the cable/circuit in between the interface and the drive might causes issues.

 

[Ozzuneoj]

I suppose if your system is corrupting the data on the CF card during boot that would explain why fdisk /mbr and sys c: fixed the problem, at least temporarily.

Do you use the same cabling regardless of whether you have the original hard disk of CF adapter/card hooked up?

Faulty cables or a loose/poor connection can cause a system to simply not detect the presence of an IDE drive. Data that is read/written is communicated in parallel, so any problems with the cable/circuit in between the interface and the drive might causes issues.

Hmm... I guess that's possible. I will try running the system with the cables removed and the hard drive just connected directly to the backplane. That would really stink if the cables don't work because it has taken me weeks to finally get my hands on some IDE extension cables after a few failed attempts at a DIY option followed by Amazon losing my package for 5 days when I finally ordered some.

Thanks for the suggestion.

 

[Ozzuneoj]

Okay, I think I am starting to get somewhere with this!

I tested the system by simply copying files over and over again. With two of the 6" extension cables attached (to make it 100x easier to swap drives) using the original hard drive and BIOS I was getting tons of the errors\crashes mentioned above. With the extensions removed and the hard drive and floppy connected directly to the backplane the situation was significantly better, but it still wasn't perfect. It would still have errors and lock up from time to time.

So, I thought maybe the backplane was the issue. It had a fair amount of white residue on it, which to me looked like flux, but I honestly don't know what it was. It did not smell fishy and the two electrolytic caps tested fine, so I don't believe it was leaked electrolyte. Regardless, I cleaned that up and then replaced the two electrolytic caps with modern low ESR caps (had to bend the legs funny on radial caps since I did not have any axials).

I then used a magnifier to check over all of the solder joints on the backplane and it looked like some of the tiny pins from the flat ribbon cables may have had broken joints. So I used some flux and reflowed all of those as well as the legs of the little yellow capacitors.

I reconnected everything and it seemed FAR better! I was able to run a full scandisk on the hard drive, copy files over and over... it was mostly working fine. Except that after some long file copy operations or other things that I walked away from, I would come back to it being unresponsive. The cursor would be blinking but I could not type anything. One time I came back after a file copy and it responded to the first key press with a beep and showed a pi symbol at the DOS prompt... which I definitely didn't type with the keyboard. Then it was frozen and would beep each time I pressed a key.

Aside from these instances, I couldn't get it to freeze up or give any errors when I was actually trying to do things.

So, I swapped the BIOS back out and reinstalled the CF card that was formatted properly for the system and had basic system files on it.

To my amazement, it is now ~90% working! I can copy things over and over and it seems to work fine... no errors at all.

However, it is still going unresponsive if I let the system sit for a moment. I tested it and I could enter gibberish commands at the DOS prompt every second for 2-3 minutes straight, I could wait ~15 seconds between entering commands and it was okay, but if I waited 30 seconds it would immediately become unresponsive. The cursor would blink but the only thing I could do was flip the switch on the back.

I think I am going to make a new thread for this because we are long past being able to pass POST and we are now into some very odd territory that I can't explain.

I am just so relieved that I've made some progress today! Thanks again for the help and suggestions Istarian.

 

[Istarian]

Best of luck with your ongoing project.

If you have a more modern system with an IDE interface, you could test the extension cables there to see if they just works or cause issues there as well.

Assuming that the extender cables aren't a problem in that environment, you might be dealing with a general issue for parallel buses or an issue specific to your GRID system.

For example:
- the parallel bus (IDE) is a little bit too long
- picking up electrical noise from the system itself or another source
- signal reflections, which is why the SCSI bus needs to be terminated

NOTE

One important thing to consider is that 80-conductor cables were standard from ATA/ATAPI-4 (UltraDMA and later) onward due to issues with 40-conductor cables and increasing speeds of data transfer.

The extra wires (aka conductors) provide both extra physical separation between regular signal carrying wires and absorption of potential crosstalk because they're connected to ground.

https://en.wikipedia.org/wiki/Signal_reflection

Ultra DMA (80-Conductor) IDE/ATA Cables