VOGONS


First post, by brassicGamer

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I obtained, by accident, an EISA motherboard 4 years ago and its taken me this long to acquire the parts and find the time to make it happen. Despite working with 486 systems since they came out, I have never worked with EISA so I expect a bit of learning. The motherboard is a TMC PET48PN like the one used by Madowax in this thread. I had no idea whether it worked or not:

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CPU is SX546:

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The case I'm using is this desktop model that was previously a 386SX/16. I think a big-ass tower would be more fitting for a 'workstation/server' CPU but hey:

file.php?id=23474

I luckily have a stash of parity SIMMs, mostly 30-pin. I have 2x 72-pin modules, which I'm saving for something else in the build, so it will be an 8MB RAM system. This is plenty for DOS, but not quite ideal for NT 3.51.

I have a selection of VLB graphics cards I have been intending to benchmark for some years now, so this will be the perfect opportunity (maybe not all will work @ 50MHz?) :

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These are the two I am most hopeful for. The S3 805 card is a Miro Crystal 10SD and has a jumper for CPUs > 33MHz. If it works I will upgrade the VRAM. The 2themax card has a ET4000 W32i under the label and has selectable wait states. The other two are Cirrus Logic chipset.

I have 2x EISA SCSI controllers. One is the Adaptec AHA-2742AT and the drivers for this are still available online so that obviously makes things much easier. I will start out with this card, as it also has a floppy controller.

The main event is the DPT SCIII:

file.php?id=80579

This is what I need the 72-pin parity SIMMs for, but I want to get the system stable before I go anywhere near it! The drivers and config files are also available online, for now at least (thanks to liqmat!)

Speaking of which, I don't have any 50-pin SCSI hard drives yet so will have to use a 9GB Fujitsu model (ridiculously incorrect for this era). I actually have no idea if I can limit the size using the controller or jumpers or what like with IDE, so I guess I'll find out. It uses the SCA connector and I have an adaptor to make it 50 pin.

The CD-ROM drive will be a Toshiba XM-5401B, which is quad speed with a 256K buffer.

I will try and post progress as I... progress.

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Reply 1 of 12, by Deksor

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We have this board in our database here : http://www.win3x.org/uh19/motherboard/show/4963

It might be too late, but can you please take a photo of the board where it's not cropped and without anything in front of it so we can add it to the base ? (pretty much the same photo as the 1st one but with the entire board in the frame).

A BIOS dump would be nice too (if you need help for that, I can tell you how to do it).

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Reply 2 of 12, by brassicGamer

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Deksor wrote on 2021-03-15, 00:35:

It might be too late, but can you please take a photo of the board where it's not cropped and without anything in front of it so we can add it to the base ? (pretty much the same photo as the 1st one but with the entire board in the frame).

A BIOS dump would be nice too (if you need help for that, I can tell you how to do it).

Luckily, I took one some years ago. Hopefully it is of good enough resolution. I will dump the BIOS once everything is up and running. 😀

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Reply 4 of 12, by red-ray

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brassicGamer wrote on 2021-03-15, 00:25:

an 8MB RAM system. This is plenty for DOS, but not quite ideal for NT 3.51.

Why NT 3.51 when NT 4.00 supports 486 CPUs and once SP6 is installed then up to 128GB disks?

I find my NT4 systems will just about run walk with 32MB, but feel 64MB is a sensible minimum

Reply 6 of 12, by brassicGamer

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red-ray wrote on 2021-03-15, 10:18:

I find my NT4 systems will just about run walk with 32MB, but feel 64MB is a sensible minimum

Because I literally only have 8MB RAM, so NT4 is out by default. I don't need the extra storage space - I'm not building a server. I'm only installing NT in the first place because I've never used 3.x. This will be my main 1993 gaming rig.

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Reply 7 of 12, by red-ray

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brassicGamer wrote on 2021-03-15, 12:50:
red-ray wrote on 2021-03-15, 10:18:

I find my NT4 systems will just about run walk with 32MB, but feel 64MB is a sensible minimum

Because I literally only have 8MB RAM, so NT4 is out by default. I don't need the extra storage space - I'm not building a server. I'm only installing NT in the first place because I've never used 3.x. This will be my main 1993 gaming rig.

In that case so is NT 3.51 as both NT 4.00 + 3.51 have a specified minimum requirement of 12 MB

Reply 8 of 12, by brassicGamer

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red-ray wrote on 2021-03-15, 13:22:

In that case so is NT 3.51 as both NT 4.00 + 3.51 have a specified minimum requirement of 12 MB

Yes, I'm aware as my original post says. It's merely an option in the future if I can obtain more. I've got original media for NT4, but I have little interest in it on this platform.

mpe wrote on 2021-03-15, 11:17:

Nice. I think you might be missing a Dallas chip in the socket to store EISA configuration.

This was the first thing I needed to fix. I have had success with purchasing Dallas replacements in the past, when I was less confident performing the coin cell mod. I looked online and found replacements for the DS1387 'RAMified' version so took a chance.

ew95Osm.jpg

When I first tested the board, it would not POST. Typically this is a CPU or RAM problem and I had actually not tested either of these components. I tested them with another board and they worked, so at least I knew they were fine. After hours of fiddling with RAM and such, I went to bed. As I was falling asleep (when I have most of my ideas) I realised that the RTC could have been the problem. Sure enough, when I swapped in the original Dallas chip, it POSTed. I'm glad I kept hold of it. So the coin-cell mod was necessary, but I don't mind now I have better skills.

I used a small file to wear away the area between the missing legs, then attached the battery holder and then soldered the wires. Works perfectly now.

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The other problem I had was that I could not boot any operating system, although I could load 'PC booter games' and very old DOS (2.11). At first I thought this was an issue with the floppy drive, but after swapping that out I tried booting from the original IDE hard drive from this system and it had the same problem. I have suspected the cache from the beginning so I disabled it in the BIOS and it worked fine. This allowed me to set up the EISA config. Now I need to get the cache working or the CPU may as well be a 386.

I will also dismantle the fake RTC 'chip' and see what is inside.

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Reply 9 of 12, by weedeewee

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brassicGamer wrote on 2021-03-15, 19:32:

I used a small file to wear away the area between the missing legs, then attached the battery holder and then soldered the wires. Works perfectly now.

I will also dismantle the fake RTC 'chip' and see what is inside.

Did you make sure to disconnect the internal battery as in cut away the metal above the chip or did you just solder your new battery directly to the first sign of metal you saw with no regard to the idea that there's an empty battery connected to the circuit ?

kinda curious as to what makes the other RTC chips so 'ramified' 😀

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Reply 10 of 12, by brassicGamer

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weedeewee wrote on 2021-03-15, 20:00:
brassicGamer wrote on 2021-03-15, 19:32:

I used a small file to wear away the area between the missing legs, then attached the battery holder and then soldered the wires. Works perfectly now.

I will also dismantle the fake RTC 'chip' and see what is inside.

Did you make sure to disconnect the internal battery as in cut away the metal above the chip or did you just solder your new battery directly to the first sign of metal you saw with no regard to the idea that there's an empty battery connected to the circuit ?

kinda curious as to what makes the other RTC chips so 'ramified' 😀

I ignored the empty battery. If it's connected in parallel, it's electrically not part of the circuit and current will instead flow by the easiest path.

There is 8KB or static RAM in the chip to save EISA configuration information.

Are there any EISA experts here? Although the motherboard configured correctly in the EISA utility, when I try to install one of the SCSI controllers, I am asked for the 'System Configuration diskette'. I have downloaded all the files that are available for the motherboard and cards. This is the error:

oG5zmhC.jpg

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Reply 11 of 12, by red-ray

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Looking at the attached installation guide you need the !adp7771.cfg and adp7770.ovl files. After a quick Google I found http://66.113.161.23/~mR_Slug/EISA/!ADP7771.CFG/

I expect the other SCSI card is much the same

Update: I just found I have the ASW-C274 v2.12 AHA-2740 Series Configuration Utilities disk which just contains the two attached files.

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  • Filename
    AHA2740.zip
    File size
    24.09 KiB
    Downloads
    18 downloads
    File comment
    ASW-C274 v2.12 AHA-2740 Series Configuration Utilities
    File license
    Public domain
  • Filename
    aha2740_ig.pdf
    File size
    63.26 KiB
    Downloads
    19 downloads
    File comment
    Installation Guide
    File license
    Public domain

Reply 12 of 12, by brassicGamer

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Nice, thanks for sharing. I'll check those against what I've already got. This particular problem with the EISA config tool is specific to that program - I think the version available online is lame, like it's missing something from the original disks. I used the AMI tool instead and this worked perfectly with this board.

I can't use the Adaptec card yet, because the ROM is apparently corrupted but I can reprogram that once the sun has done its magic on a spare EPROM (I have a UV eraser on its way from China, but even in England I think the natural approach will work sooner!)

Also there is an issue with the drivers for the DPT caching controller which also requires a disk that apparently doesn't exist, despite me having all the files available online. Without original diskettes from someone I will have to work this out later, but for now I just want a working system. I don't mind using IDE in the meantime, as I can benchmark the system to hell and establish a baseline. From there I can start to upgrade everything and see the incremental improvements:

- Storage: IDE -> SCSI
- Graphics: IDE -> VLB
- I/O controller: ISA IDE -> ISA caching IDE -> EISA SCSI -> EISA caching SCSI -> VLB IDE -> VLB caching IDE
- RAM: 30-pin -> 72-pin

I don't have a VLB SCSI controller, tough I'm not sure 50MHz SCSI is a good idea! As such I'm not trying to see what is best, rather how big the performance differential is out of curiosity. Each has their own benefits (e.g. stability of EISA vs raw speed of VLB).

Presently the cache on the board is not working. Disabling the external cache in the BIOS allows the system to boot, as I don't believe the cache can be disabled on the motherboard. All the cache that was originally installed was not included, just two 64K x 1 chips. These are used to supplement the TAG in a 512KB configuration, allowing the full 128MB RAM to be cached. I don't have the cache chips required to make 512KB (four 128K x 8 chips), so I need to replace the 64K chips with 16K. These are readily available, whereas the 512KB cache is not. I also do not require the full cache as I do not have much RAM.

In terms of sound, I would eventually like this to be my early-era DOS gaming machine, for running VGA games. As such, it will be equipped with a Sound Blaster CT1350B with CMS option, Gravis Ultrasound, and Voyetra intelligent MIDI card for use with MT-32 and SC55. This should provide compatibility for the vast majority of games of this era.

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