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Suntac 80286 Mainboards

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Reply 160 of 174, by Robin4

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MMaximus wrote on 2019-06-04, 17:18:
So... I'm having RAM issues while trying to set up another Suntac board. This particular board supports SIPP memory, but since I […]
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So... I'm having RAM issues while trying to set up another Suntac board. This particular board supports SIPP memory, but since I only have 256kb SIPP modules, I'm trying to make it work with 1Mb SIMM modules in SIMM holders inserted into the SIPP slots.

The DIP switches for memory are set correctly on the mobo and it reports the correct memory size (4Mb). It posts without problem, but when I run a memory test in Checkit, I get lots of errors. I removed the SIMM modules from their holders and put them into a 386 board to test, and Checkit doesn't find any error so I assume the SIMMS are ok.

On the Suntac mobo there are 3 jumpers next to the DIP sockets: RAS, CASL, and CASH. I'm thinking maybe they're set incorrectly and that's why Checkit is finding errors? I've tested the 256kb SIPP modules and the Checkit test runs ok - it only happens with the 1M SIMMs (which are all 9 chip modules).

Any ideas?

Maybe its not possible to use the DIP ram and the SIPP modules at the same time.. Could be that you have to use 1 of the time.. Or the timings are set to low (quick) and the memory cant handle those speeds.

~ At least it can do black and white~

Reply 161 of 174, by HanJammer

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Robin4 wrote on 2021-01-15, 10:57:
MR-BIOS and the AMI bios that i downloaded from one of your boards (was the second one) work ok. (thanks for that). System goes […]
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MR-BIOS and the AMI bios that i downloaded from one of your boards (was the second one) work ok. (thanks for that). System goes on.. Both non-working keyboard (locked) and also got a keyboard error.

With the original Phoenix roms its works just fine, and also the keyboard working fine. So the keyboard controller which i know is working and it came with the Phoenix bios set. Doesnt seems to work with the AMI BIOS set and MR BIOS SET.
I also tested it with a working AWARD 286 bios set and i gave me also a keyboard error / non working keyboard.

So my conclusion here is that Other bios sets then Phoenix bios would not work with that phoenix compatible keyboard controller / keyboard bios chip)
Also tried a second M5L8042 which gave me an keyboard error.

Maybe the ICs are pin compatible, but keyboard bios code maybe not.

Again - no such thing as keyboard bios or keyboard bios chip. It's just keyboard controller.

Have you tried locking/unlocking keyboard lock switch with the AMI/MrBIOSes you installed? Could you check part number of the original KBC chip and the one you tried to install?

Check out my AmiBay and eBay for vintage PC hardware.

Reply 162 of 174, by Robin4

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Update:

Tried the AMI bios set again. (also swapped out the Keyboard bios (a second one) from the same kind.
With that second keyboard bios and original Phoenix bios it would hang on post.
Swapped the keyboard bios with the first one. And then inserting the AMI set again..
Seems kinda works now.. Its only very slow when pushing DEL key on the keyboard to entering the bios setup utility..

AND TADA.. The AMI roms gave me support for TYPE 47 USER SETTINGS... Dont know what the max is But till 504MB is just fine for me with this 286 board. Also dont know why this board is so slow for a 286 machine.. Knowing its one of the earlier boards iam guessing.. I see Year marks like 1985 on those Phoenix bios roms.. And also not sure if these where the original roms or not. It maybe was swapped or replaced when the previously owner had this board in posession.

Also sprayed every ic socket or isa slot in with deoxit D5.. That was really needed due dried / oxide. Also revived an older ISA floppy / hdd controller card, which wont worked before. Removed the PAL chip and sprayed the PAL socket with Deoxit D5 and put the IC back in place. Working again.

Have you tried locking/unlocking keyboard lock switch with the AMI/MrBIOSes you installed? Could you check part number of the original KBC chip and the one you tried to install?

The board is outside of any case. For testing purpose. It ran already 2 of 3 times before with a working keyboard (with the older roms phoenix installed)
The KBC chip is just the one that came on this board. The second one i pulled out of one of my other 286 suntac boards that needs te be repaired.
(but was from the same type as from board 1)

~ At least it can do black and white~

Reply 164 of 174, by fgenesis

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Just wanted to say thanks for this thread and all the BIOS images within. I've managed to save an old Suntac 286 board, exactly this one: http://www.win3x.org/uh19/motherboard/show/955 .
Someone had taken out both BIOS chips and most of the RAM (but left in the leaky battery, grrr) and it has spent some time in storage before I decided to check again and found the new UH19 entry.
Got some RAM and after a lot of fiddling caused by a dead chip here's a quick BIOS review, for completeness:
- Award: works, but doesn't beep, so no way to detect the bad RAM. Not helpful with a POST debug card either. The most spartan and generally worst of the BIOSes. Does the job once it works, but still meh.
- AMI: Beeps with dead RAM, but doesn't POST because it fails to detect the keyboard controller
- Phoenix: So-so, forgot the details but wasn't that helpful in diagnosing the issue. But it works with the keyboard controller and has some more features than the Award one.

And the best: MR-BIOS!
Did the important tests right at the start:
I had forgotten to change a dip switch from 27C128 to 27C256. 3 beeps, whoops, detected and fixed.
Then 4 beeps, base 64k fail. Found the bad chip after a lot of trial and error.
IDE cable orientation wrong? More beeping!
This bios is definitely the best of the bunch, also feature-wise.

It appears to have some problems with an SD<->IDE adapter (not sure if hw problem or not, the thing works fine in a 486 machine) but works with a 16 GB CF card truncated to 8 GB.
For reference, Cyl=15603 Hd=16 Sec=63 with Translate=No; translate=Yes hangs after POST. DOS doesn't like this translate feature for some reason. Hangs even if booted from floppy so maybe the disk detection is entirely messed up with translate on.
EZ-Drive on top for good measure and the board is as good as new, now. Yay.

EDIT: Might also mention this because it's not obvious, imho:
Haven't seen a BIOS before that uses alternate reboot hotkeys. Instead of entering the setup via Del or F2 during POST, MR-BIOS reboots into setup when pressing Ctrl+Alt+Esc. Ctrl+Alt+Enter goes into a boot drive selection. Can only boot from the first floppy or first disk, but hey, better than nothing.

Reply 165 of 174, by zoinknoise

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crossposting from the main 286 BIOS thread...

here's yet another Award BIOS. interesting how these old Suntac boards all look nearly the same, and yet each one has its own bespoke BIOS. this is Award version 3.03HL, but it's twice as large as the version already dumped (64k instead of 32k, and it's not an overdump either)

i was annoyed to see it ONLY supports preset hard drive sizes 😠 so i am using the MR-BIOS instead. (which itself isn't ideal; it doesn't recognize my 287 and it's not clear if it supports parity, but good enough for now)

protip for anyone with these boards who can't get them working: touch up the soldering joints on the bottom, and around the chipset, and keep checking for signs of life with a POSTcard. (not at the same time of course) that's what i had to do with mine to get it working. these boards are very old now and the solder joints, which on my board are mostly half-empty, are probably full of microcracks.

also, this board works GREAT at 16mhz! apparently the ST62 chipset is only specified for 12mhz maximum, but i desoldered the oscillator, installed a socket, dropped in a 32mhz osc and it's rock solid so far. i am even using the original AMD 286-12 processor (with a heatsink of course 😉) just for fun, i tried a Harris 286-20 with a 40mhz osc. the board still booted (!) but only with the controller card removed. haha, oh well.

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Reply 167 of 174, by zoinknoise

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Predator99 wrote on 2021-06-09, 22:01:

Thanks for providing the image. Its indeed an overdump. The 1st 32kb are identical to the 2nd 32kb.
I checked your combined file "suntac 286 [Award 3.03HL].bin"

hmm, interesting. the jumper on the board was set to 256kbit ROMs. i stand corrected!

Reply 168 of 174, by Predator99

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Yes but I think in this case the setting of the jumper doesnt matter...try to switch to 27128 and it should still work.

Take a look at the AMI diagnostic ROMs, they have a size of 64 kbyte.

Reply 169 of 174, by Deunan

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My mobo started acting a bit strange lately. It seems to corrupt reads done via 16-bit I/O, that's my diagnosis for now. One VGA card shows text with random spots getting yellow/orange color and background. Trident 8900C doesn't do that but it too will start corrupting screen when I run Norton Commander 4 and flip the windows on/off - then the blue background attribute stays in random places. This BTW also corrupts fonts on the first VGA. But all these problems go away when the video card is in 8-bit slot.
Then there are random disk read failures (CF card, not HDD) but never on floppy. As the system warms up I eventually can't even boot DOS anymore. This seems to go away with VGA in 8-bit slot but I suspect it's only because HDD reads are kinda slow on their own, it probably doesn't trigger the issue nearly as often. Oh, and also random keyboard hangs, need to reset the system to get the keyboard back, though once it came back after I started messing around with the mobo.

At first I though it's a general isssue with ISA slots conflicting with on-board chips so I desoldered and socketed the 74ALS245. I tried a replacement, no change, so that's not it. I couldn't find any more cracked solder joints so I retouched all the mobo chips, and on my mobo some of them are in really tight spots. I touched 2 ISA slots with the soldering iron - just the ends, but I'm not happy about the damage, however small. Suffice to say all that work didn't pay off, nothing changed. Also, the fresh solder on the pads sort of ruins the mobo looks now...

I'm slowly running out of ideas, perhaps I have a faulty mobo chip. I'm going to rotate RAM chips, just in case, but I don't think it's RAM since I once got the 3DBench test running happily but the keyboard hanged. It seems having HIMEM loaded somehow makes it worse so worth a try. Or it could be another via issue but I tested pretty much all the ISA to chipset connections and found no issues.

Has anyone seen or had problems like these? If so, what was causing it? I could sope the extended ISA signals but since the corruption is random and not all that frequent I might be looking for a needle in a haystack...

Reply 170 of 174, by zoinknoise

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Deunan wrote on 2021-06-09, 23:19:

I'm slowly running out of ideas, perhaps I have a faulty mobo chip. I'm going to rotate RAM chips, just in case, but I don't think it's RAM since I once got the 3DBench test running happily but the keyboard hanged.

sorry about the cosmetic damage to your board. don't beat yourself up over it. it is better to have a working device with a few tiny blemishes, than a mint condition device that performs unreliably. i have ruined motherboard traces a few times when desoldering bad RAM chips or Dallas clock chips, etc, and had to fix them up with a bit of wire. but now those boards work perfectly, so i have no regrets.

my advice is: RAM RAM RAM. always suspect the RAM first. even SRAM chips of this age are starting to go bad, and DRAM has always been far less reliable than SRAM. bad DRAM chips are *everywhere* now.

if you get really desperate, you can always just bake the board 😀 just because you can't see
microcracks in solder joints doesn't mean they aren't there 😉

Reply 171 of 174, by Deunan

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Yeah, I'm really unhappy about the soldering, I should've run more tests but it was already day 2 of doing just that and I was getting nowhere. It's one thing when it's necessary to solder stuff, and another when it does nothing and I make a so-so job of it... Oh well. It works - as well as it did, anyway.

So I didn't touch RAMs yet, although I have to say the entire bank is NOS chips and I did test them before I populated the mobo (but that was months ago). Today I went after the HIMEM issues and I found that even enabling A20 gate with my own code I get these problems. So here's some more observations:

- A20 gate is controlled by KBC and the only chip that seems to receive that signal is the ST62BC002 / HADR, it controls how CPU address lines get passed to memory (depending on switch configuration) and to ISA slots.
- When A20 gate is disabled, everything is OK. Enabling it, just flipping that one KBC output port bit, starts the problems with 16-bit VGAs.
- Because the mobo reboots with A20 enabled (BIOS disables it when booting OS) I get the screen corruption even during memory check.
- It really helps if the VGA card is installed in the slot next to KBC and '245 chip, I get almost perfect operation, but there are still some randomly corrupted spots, just way more rarely than in other slots.
- MR BIOS solved my CF card problems, so I guess that was unrelated and down to this particular card. It's a great BIOS too, nice look, fast booting.
- For some reason I'm unable to run NSSI while using MR BIOS, it hangs on bus detection even with /SAFE switch, this is not happening with original AMI BIOS. Same with Snooper.
- Also, 1024x768 modes on Trident 8900C VGA hang with MR BIOS, but work fine with AMI. Other modes, including SVGA, seem to work fine on both.

Frankly I could just roll with MR BIOS and use Trident in the lowest slot, that would almost eliminate all the video and CF card problems, if it wasn't for the fact that NSSI and Snooper hang. I could just not use them but I don't like that. I do not get why A20 gate is affecting ISA in that way - is my '002 chip busted or is it yet another thing with this mobo and video cards. It does not boot at all with Trident 8900D, I suspect the ALE signal is toggling during memory refresh, it's a known issue with some mobos.

Also, somewhat related, XTIDE ROM doesn't really solve the CF card issues I had, but MR BIOS did. Maybe if I used the bigger XTIDE version (over 8KiB)...

EDIT: To clarify, this issue might not be a recent development, it's possible the mobo was always like that but until now I did mostly run benchmarks with no HIMEM (so A20 gate disabled) and/or with the Trident 8900C in the lowest slot so I just didn't notice any problems. I was also using a different CF card, that I move around for testing, now I've swtiched to a card I was hoping to use with this system.

Reply 172 of 174, by MMaximus

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zoinknoise wrote on 2021-06-09, 18:20:
crossposting from the main 286 BIOS thread... […]
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crossposting from the main 286 BIOS thread...

here's yet another Award BIOS. interesting how these old Suntac boards all look nearly the same, and yet each one has its own bespoke BIOS. this is Award version 3.03HL, but it's twice as large as the version already dumped (64k instead of 32k, and it's not an overdump either)

i was annoyed to see it ONLY supports preset hard drive sizes 😠 so i am using the MR-BIOS instead. (which itself isn't ideal; it doesn't recognize my 287 and it's not clear if it supports parity, but good enough for now)

protip for anyone with these boards who can't get them working: touch up the soldering joints on the bottom, and around the chipset, and keep checking for signs of life with a POSTcard. (not at the same time of course) that's what i had to do with mine to get it working. these boards are very old now and the solder joints, which on my board are mostly half-empty, are probably full of microcracks.

also, this board works GREAT at 16mhz! apparently the ST62 chipset is only specified for 12mhz maximum, but i desoldered the oscillator, installed a socket, dropped in a 32mhz osc and it's rock solid so far. i am even using the original AMD 286-12 processor (with a heatsink of course 😉) just for fun, i tried a Harris 286-20 with a 40mhz osc. the board still booted (!) but only with the controller card removed. haha, oh well.

IMG_3539.jpg

Good to know that the board works at 16Mhz! I'd be interested to know the performance in benchmarks to see how it compares to let's say, a 16Mhz Octek Fox 2 with the more recent Headland Chipset.

I've had quite a few 286 boards and the Suntac one is the best performing 12Mhz. I've always disliked its very basic Phoenix BIOS so lately I tried the MR-Bios in it, it seems to work well but I don't know if it's that stable - for example I can't use NSSI anymore, the program won't start even though it works well with the Phoenix BIOS.

Reply 173 of 174, by maxtherabbit

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as a side note I also tried the generic 286 MR BIOS on my VLSI chipset 286 system and Windows 3.1 would no longer work

switched back to the AMI BIOS and everything was right as rain

Reply 174 of 174, by zoinknoise

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re: MR-BIOS, i have mixed feelings about it too. i am blown away that anyone even bothered to make such a BIOS in 1994, but yeah, it's got its own shortcomings.

i suspect that it really was intended for actual, original IBM AT motherboards, or clone boards built the same way (i.e. with a fully discrete chipset). the name "STD_286" in the menu is a clue: Standard 286.

Deunan wrote on 2021-06-10, 22:29:

So I didn't touch RAMs yet, although I have to say the entire bank is NOS chips and I did test them before I populated the mobo (but that was months ago).

NOS means nothing with RAM chips. in fact i would be more suspicious of NOS memory chips, and i immediately test them upon acquiring, as you did. but they can still go bad just like any other old RAM chip.

just like with most electronics, memory chips don't really care if they are on or off, as long as they don't overheat and damage themselves. they can go bad just sitting on the shelf.

case in point: as i was writing this post, i was troubleshooting why my Super7 machine was acting so strangely, so i ram RAMtest+, and sure enough, one of the two 128MB sticks is bad. they are high quality sticks too: CL2 PC133 made by Infineon. see my point? nobody is safe. 😀