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A new covid lockdown project - help if you can

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Reply 20 of 166, by kool kitty89

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The Quadtel labeled chip should just be a (semi) generic keyboard controller, mostly interchangeable between boards (sometimes NMOS vs CMOS and speed related issues depend and/or A20 handler implementations) and shouldn't be storing any BIOS parameters.

The realtime clock chip usually contains a small amount of static RAM for CMOS/BIOS settings, and the chipset itself might have some scratchpad memory for the same purpose, but there's odd cases where data remains even with no battery and all capacitors discharged, and I'm not sure how that works.

I have a PCChips M205 (not PCChips branded, but same board) that does that same thing, and I haven't tried swapping the BIOS to compare settings, but it retains disk parameters and EMS memory selection without power somehow (date/time as well as shadow RAM configuration get wiped, though).

The capacitors on that board also keep CMOS RAM powered for a surprisingly long time, which made the situation more confusing.

It could either be a small amount of EEPROM somewhere in the chipset or genuine NVRAM of some sort, maybe FERAM. (it had a short fad in the early 90s and ended up getting used by Sega briefly as the 8kB save RAM inside Sonic 3 carts, but I'm not sure if that could be the case: Sega's example also has a fairly high failure rate with unknown expiration date)

Anyway, I'd think a generic IDE/floppy or multi I/O ISA card would work fine for connecting IDE drives (and Compact Flash) to that board. It's worked fine for my 286 boards, though if you don't have old/small enough drives (or CF cards with known Cylinder/Head/Sector configurations) that would be less useful than XTIDE with large disk support.

IDE drives old enough to feature capacity limit jumpers should also work for any boards that don't have a BIOS with the 528 MB capacity limit (1024-16-63).

My 1990 vintage M205 worked fine with an old 2.5 GB drive I don't have anymore (it was Apolloboy's 286 build at the time and he kept the drive and since sold/traded it) and I swear it wasn't even in cap-limit mode and worked fine, and the settings were even still in the BIOS when I checked last year, but I didn't write them down or take a picture, so I'm not sure of the C/H/S count.

I think it may have been a Western Digital Caviar 32500 (those look like what I remember) and those are 4960/16/63. (which implies that BIOS might work all the way up to the 8GB limit ... though it lets you input values beyond that with a 255 Head limit and 65536kB total address/capacity limit, which seems common to a number of early 90s AMI BIOSs, 16-bit integer limit to the capacity description)

That's with a 1988 dated AMI BIOS (1990 date in the POST and set-up screens, but 1988 copyright on the sticker), and I have a Quadtel BIOS 286 I could try for comparison.

In any case, is you have any old IDE drives kicking around, it'd be worth a shot.

Did that machine come with an IDE drive and interface card or is that SCSI? It looks like a 40-wire IDE cable to me, but it's hard to tell from the photos.

Smaller CF cards (up to 1 GB) should work OK too with the correct C/H/S input, if you already have a CF to 40 pin IDE adapter. (I'd assume you would if you have the 40-pin IDE XTIDE card, but might not if it's the native CF adapter)

The color of that PCB really reminds me of some PCChips or Hedaka (Llion, etc) boards from that period, but did they build any with CHIPS and Technology chipsets? (I've seen Citygate based M209 boards by them with C&T DMA/clock ASICs, but not C&S chipsets)

It could just be coincidence, though, just superficial resemblance. (oddly enough, the Motorola based IDE/floppy interface card Apolloboy and I originally used with the M205 matched that PCB style, too)

Then you've got to get some chipset drivers working with this thing, especially assuming it has integrated EMS support. It looks like a fairly late, highly integrated chipset (1990-ish, that '9042' could be a 1990 date stamp too) and probably would run a good deal faster than that 12 MHz. You need a socket for that osccilator and a 286-16 or 20 to try with 32-50 MHz oscillators. If wait states are like my M205, that 70 ns RAM would work fine at 20 MHz anyway, maybe 22 or 25. (if it's zero wait state, maybe 16-20 MHz depending on the chipset's speed/tolerances)

Also neat to see an old XT clone box with an upgrade board inside like that. I swear it was one of those with a K6 badge stuck on it that I almost got as a freeby about 10 years ago, no idea what was inside it. (a guy was dropping it off at WeirdStuff Warehouse and offered it when I passed him in the parking lot)

Reply 21 of 166, by kool kitty89

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Addendum to the keyboard controller comment above:
it was very very common for keyboard controllers to come in matched pairs with BIOS ROMs/EPROMs/EEPROMs and/or have stick-on matching labels for both. There are tons of "AMI KEYBOARD BIOS" labeled 40-pin DIPS out there that should be nothing more than industry standard AT keyboard controllers (some later models with multiple keyboard support and/or explicit PS/2 keyboard + mouse support) but I'm pretty sure most are cross-compatible and pin-compatible with the old intel microcontroller IBM used in the AT.

The only legitimate 'BIOS' part of those chips should be the mask ROM on board for the microcontroller. I'm not sure if AMI themselves engineered their own IBM-compatible microcontroller ROM or used someone else's. (Jetkey was a common one, and plenty of boards have unmarked Intel microcontrollers on them, or intel chips with labels stuck on)

Vipersan wrote on 2020-03-24, 19:15:
Found it I think ... I gently peeled back the CHIPS Bios sticker to reveal the chip number MB-1212C ..which gave me something e […]
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Found it I think ...
I gently peeled back the CHIPS Bios sticker to reveal the chip number
MB-1212C
..which gave me something else to search for..
Instantly linked to this page..
https://arvutimuuseum.ee/th99/m/A-B/30697.htm
and there was a outline of my motherboard.

here are the details ..made by Biostar Microtech International

BIOSTAR MICROTECH INTERNATIONAL CORPORATION

MB-1212C

Darn, I skipped over this post somehow and was looking through Stason's list of 286 boards and just found that one, then scrolled back and found your post.

https://stason.org/TULARC/pc/motherboards/m286_1.html
https://stason.org/TULARC/pc/motherboards/B/B … N-286-MB-2.html

Looks like most of the same data as arvutimuuseum, though the dimensions are different at 244x218mm

It came in SIPP and SIMM variants and a very similar 16 MHz board also exists:
https://stason.org/TULARC/pc/motherboards/B/B … N-286-MB-5.html

Other than the 2 BIOS sockets, that looks nearly identical. (though Biostar had several other boards with non-C&T chipsets and very similar layouts)

Reply 22 of 166, by Vipersan

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Thanks for the very comprehensive posts Kool Kitty ..
Yes it is indeed a nice looking board ..and I really want to get it as functional as possible.
Though as I said I am a bit out of my comfort zone with this ..my earliest PC encounters being 386 prior.

No it came with a floppy/IDE controller ISA card (Generic I suppose) ..the only Identification on it being PM-510C
And was fitted with a WD 95044 hard drive ..sadly that has gone to meet its maker.
The reason I mention SCSI a lot is that this was the only way so far to get DOS 6.22 working in the 286.
I fitted an ISA scsi card ...and hooked up the only working old scsi hard drive I have ..
820mb ...but was not able to use it with the scsis built in floppy ..or indeed the PM-510 floppy controller.
I simply couldn't boot from floppy.
So ..
I Installed DOS 6.22 on the 820mb scsi by mounting it in a much later 90s PC fitted with a pci scsi controller and floppy drive.
Then mounted the pre-prepared hard drive in the 286 again ..using the ISA scsi controller..
It worked ..and just for good measure popped Maniac Mansion on it to prove the Trident VGA I chose worked ok in the 286.
(It didn't come with anything close to VGA CGA EGA ..just an 8 bit ISA MDA.
So ..no way to hook up a monitor for me.
I'm attaching a poor photo of this working.

What I am pondering is using a suitably flashed eprom ..containing a suitable XT-IDE bios in an ISA network card.
I know this has been done before ...but I need an 8k bin dump of a suitable bios to try this.
256k eprom with the bios repeated 4 times I believe so as to catch the start page boundry of the bios.

any further help you want to give would make for enlightening reading..
cheers K K

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Reply 24 of 166, by Vipersan

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So ..I have now tried 2 controller card ...
..I found a good working Seagate 3120A (120mb) IDE hard drive.
No way will my motherboards bios play nice with this drive.
There are no presets for this so is treated very much as an unknown.
There is however a user defined option in the bios setup ..
..so set as > Heads 12 - Cylinders 1024 - Sectors 17 - Bytes per Sec 512
Which as far as I know and according to googled info is correct ...and with both controllers ...I get disk failure ...fix problem and reboot.
So I can only assume the bios simply cannot support even the 3120A 120mb drive
I think I have a conner CP3104 100mb drive somewhere and it's geometry is supported ..but the drive if I remember right is fubarred.
So unless I can get a bios that supports larger drives I am fooked.
rgds
VS

Reply 25 of 166, by elianda

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Just some things to check:
The ST3120A works on another computer?
So the drive is jumpered master (4th jumper away from the power connector closed) ?
The cable is connected correctly with red to pin 1 and red towards the power connector of the drive?
The drive is connected at the end of the cable?
Have you tried to use 1023 cylinders instead of 1024? Maybe the BIOS has a boundary problem?
Does some preset with a lower CHS setting work (for each value of CHS)?

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Reply 26 of 166, by Vipersan

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Hi elinda ..yes the ST3120 works fine on other computers and is set to master.
I must admit I haven't tried any other CHS settings other than those defined as correct ..presumably by the manual ..or online.
The issues do appear to centre around the limitations of the motherboard/bios combination.
I think I have already concluded that I cannot use a large hard drive ...and probably none with a user defined CHS resulting in a capacity larger than 100mb.

On a different tack ...I found a 32mb Drive on Module ..amongst my retro kit ...and popped this in the XT-IDE 8 bit ISA cards IDE connector..
I really didn't expect it to work ..but it did..
I managed to install DOS6.22 from floppy to it ..and it booted.
Mind blown ...
here are some pics including scandisk running on the D O M
rgds
VS

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Reply 27 of 166, by Vipersan

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Looks like I might get away with a 64mb CF ...but I dont have anything less than 1gb.
So ..I'll have to obtain one to try.
In conclusion...I think I am limited to hard drive capacity ..unless I can replace the bios with something more recent than the CHIPS version already on the mobo.
..or I can persuade the XT-IDE card to play nice with a larger CF
If all else fails there is always the SCSI option I guess..

Reply 28 of 166, by Vipersan

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So I hooked a 2gb CF to the XT-IDE card ...rebooted and tried again to install DOS 6.22
Failed again with non system disk error
Tried the same thing with the ST3120 connected ..
Same fail ..non system disk error.
So no chance of installing DOS 6.22 on either.
I guess it is indeed the hard drive size which somehow the motherboard/bios is refusing to use even though XT-IDE is in control.
and yet my 32mb Drive ON Module is accepted.
I guess I just have to learn to live with a hard drive of <> 100mb.
Unless someone knows different ?
I'll keep searching for a later BIOS for this motherboard ..but I'm not hopeful.
rgds
VS

Reply 29 of 166, by pentiumspeed

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Use the BIOS without XT IDE card to choose a size, for example 40MB or 60MB type number and delete the partitions on the 64MB Cf then create new partition then format. This will work as 40MB or 60MB. If you have a 128MB CF, use it as 80MB or some where less than 110MB from your table of type numbers in BIOS.

I did this with a large IDE hard drive and a multi-i/o card via IDE port. Does boot.

Cheers,

Great Northern aka Canada.

Reply 30 of 166, by Vipersan

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Found my Conner CP-3104 104mb hard drive ...and opened it up ..
Very carefully cleaned any crap out of it ...
checked what I can see platter wise ..
all looks good ..
reassembled and mounted it with CHS settings >> CP-3104 ATA 105MB 776 8 33
Which is a geometry the bios _does_ natively support
Also mounted my SCSI drive and adapter card.
and the DOM XT-IDE all at the same time.
This allows me to boot from the DOMs DOS 6.22 as I have no floppy control with this configuration.
Currently using Xcopy to grab the entire contents of the Conner ..and dump them on the scsi hard drive using the DOM as intermediary.
So far this is working ..but likely to take a long time.
I'm finding very old games and software on the Conner which used to be fitted in my Toshiba T5200/100 luggable...before It was retrofitted with a custom bios making 44pin IDE drives viable.
JaZz will remember that process from over a year ago. (that project is logged on Vogons)
So I get to rescue that OS ..and hopefully re-use the Conner in this project.
Assuming it keeps running.
rgds
VS

Reply 31 of 166, by Vipersan

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All the contents of the Conner rescued..
Formatted ok
Currently running SCANDISK ..with a surface scan ..a good idea under the circumstances.
If all goes well at least I should have 104mb for my DOS 6.22 OS
rgds
VS

Reply 32 of 166, by jaZz_KCS

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Vipersan wrote on 2020-03-26, 12:43:
All the contents of the Conner rescued.. Formatted ok Currently running SCANDISK ..with a surface scan ..a good idea under the c […]
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All the contents of the Conner rescued..
Formatted ok
Currently running SCANDISK ..with a surface scan ..a good idea under the circumstances.
If all goes well at least I should have 104mb for my DOS 6.22 OS
rgds
VS

Considering the horsepower of this little beauty, this seems enough for any purpose 😉

Reply 33 of 166, by Vipersan

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Indeed it is JZ ..My only real concern is for the longevity of the Conner..
Still it has at least given me opportunity to rescue it's contents ..and a great teaching experience regarding data recovery for old gemetry drives.
I may even use the same process to take a looksee if data can be recovered from the original 43mb WD beast.
rgds
VS

Reply 35 of 166, by Vipersan

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So ..thats not gonna happen ..
Once again the bios stepped in to halt the DOS 6.22 install process at around 3% or IO.sys
fekkin bios AGAIN ...
I can see no way to do this other than To use XT-IDE with a hard drive under 100mb or SCSI hard drive and SCSI adapter ..which allow hard drives greater than 100mb but no floppy access thereafter.
I guess I might try an earlier version of DOS with the Conner ..but I'm not hopeful.
I even tried formatting the conner ...then used the DOM and copied 6.22 in its entirity over to the Conner..
The OS files transferred ok ..but the PC refused to boot claiming the Conner was a non system disk.

Reply 37 of 166, by Vipersan

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Not celebrating ..YET ...but swapped out the CHIPS Bios for the GW-GEAR bios chip I flashed the other day..
..and looks like DOS 5 is installing to the Conner.
It's painfully slow going ..but halfway through disk 2

Reply 38 of 166, by Vipersan

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So it looks like DOS 5 installed to the Conner ..but of _course_ it wouldn't boot ...why would it ?
That would be too easy.
Made an MSDOS start up floppy so I could at least take a look at the fdisk partition information of the conner..
No space available and reporting as a NON DOS Partition
So ..back to basics ..
This time re -installed DOS 5 but interrupted the setup process to access FDisk ...and format
This time upon completing the installation I rebooted to the MS DOS5 Shell ..
So that works..
Still no chance of installing DOS 6.22 to the Conner.
But this has to be a Bios issue.
Until I replaced the CHIPS BIOS with GW-GEAR Bios even DOS 5 wasn't possible.
Any advance on the GW-GEAR bios ...anyone ???
rgds
VS

Reply 39 of 166, by Intel486dx33

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I love the sound of those old Conner drives.
They produce the best retro hard-drive ticking sound.

Don't forget your AntiVirus software.
https://www.ebay.com/itm/Vintage1997-SYMANTEC … Y4AAOSwMo9a4Dgu

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