2024-08-10 | [retrocomputing]
This is one of those neat computers which has an orange gas plasma display, which is pretty cool. It's the only 386 era machine I have, and besides that, it's a little bit custom compared to a standard PC. Here's a few notes about getting it working:
This unit does not have a bios setting utility built in to the rom, it uses one you run from within DOS. So, you need to make sure:
The battery is good (it can be a normal non-rechargeable lithium - I used a CR123 cell in mine and it seems to work fine)
The floppy drive needs to work
I could not find a 1.2 Mb image of the diagnostic disk, so I made my own (ImageDisk format. I'm not sure if it works with FlashFloppy but it should be convertible to a format that can by the HxC Utility). If you boot this and run SETUP, it will take you into the bios program where you can set things up. The SETUP I found will also run from within DOS 6.22 - not all ones I tired would do that (the machine originally shipped with I think DOS 3)
It uses IDE hard drives, supposedly one of the earliest to do so. It can support two of them in Master / Slave configurations, but you have to select from only a short list of types which were available at the time.
Both of my units came with a seemingly working Conner CP-341 drive, which is about 40 MiB capacity. These are pretty interesting, apparently they have a diagnostic RS232 port which you can connect to and make it do stuff (I didn't look at this yet). Apart from that, and the fact that they are "the first IDE drives", I didn't find any other useful information (no manuals). So I didn't know how to adjust the drive so it could work with a CF card as a second drive.
I did find a sheet for a probably similar drive, the CP-342, which has this note:
**********************************************************************
G E N E R A L
**********************************************************************
CONNER CP-342 + WD
Jumper Setting
==============
J8
+5-3-1+ +-----+ +-----+
Master |X * *| |* X *| |* X X|
E6-E7 Closed |X * *| |* X *| |* X X|WD DRIVE
+6-4-2+ +-----+ +-----+
Single Master Slave Slave
E5-E7 Closed
Slave
E6 Closed
Installation with a WD93024A/95024A/93028AD/93048AD!
WD drive must be configured as SLAVE!
Conner drive must be configured as MASTER!
On my drive, I found that these jumper settings did seem to be correct. I also found that, working with a Compact Flash, the Conner drive also did need to be jumpered into Slave for it to work. It seems that it will not work as a Master.
Update: My Conner drives seem to still work, but have at least once suffered stiction (motor can't overcome static friction at startup). Shaking the computer wasn't enough; I had to take the drive out and give it a sharp spinning whack to get the disk turning again. For this reason, I'm just going to keep the CF card for now.
Well yes, you can use a Compact Flash Card instead, since it sill uses (effectively) an IDE interface. It's not a free for all; for example, I don't think you can use one with a capacity bigger than 2Gb. You also have to use special software to get it to use disk sizes which are not included in the BIOS. This page has some more details on that.
I may not have read the instructions, but it seems that the Ontrack drive overlay is supposed to work by first installing it on your drive, then installing the OS on it like any other drive.
Per Retropaq.com, these are the 47 types of drives you can pick from, arranged by capacity:
Size MiB BIOS # Cyli Head Sectors Write Landing
nder s Precomp Zone
10.16 1 306 4 17 128 305
20.32 16 612 4 17 0 612
20.42 2 615 4 17 128 638
20.439 44 805 2 26 -1 805
28.928 6 697 5 17 128 696
30.029 30 615 4 25 128 615
30.422 20 733 5 17 256 732
30.63 3 615 6 17 128 615
30.68 7 462 8 17 256 511
32.539 14 980 4 17 128 980
38.391 8 925 5 17 128 924
40.093 22 805 6 17 -1 805
40.641 13 612 8 17 256 611
40.674 10 980 5 17 -1 980
40.674 17 980 5 17 128 980
40.879 43 805 4 26 -1 805
42.591 21 733 7 17 256 732
46.816 5 940 6 17 512 939
48.111 18 966 6 17 128 966
53.748 11 925 7 17 128 924
58.96 47 966 5 25 128 966
60.059 31 615 8 25 128 615
61.318 29 805 6 26 -1 805
61.359 23 924 8 17 -1 924
67.934 19 1023 8 17 -1 1023
68 4 1024 8 17 512 1023
69.104 12 925 9 17 128 924
72.316 46 748 6 33 -1 748
80.186 27 966 10 17 -1 966
80.186 37 966 5 34 -1 966
96.422 45 748 8 33 -1 748
99.344 28 748 16 17 -1 748
99.344 33 748 8 34 -1 748
99.426 32 905 9 25 128 905
112.061 9 900 15 17 -1 899
112.26 24 966 14 17 -1 966
112.26 34 966 7 34 -1 966
118.884 26 1023 14 17 -1 1023
128.297 25 966 16 17 -1 966
128.297 35 966 8 34 -1 966
144.334 36 966 9 34 -1 966
181.323 39 1023 11 33 -1 1023
247.258 41 1023 15 33 -1 1023
254.751 40 1023 15 34 -1 1023
300.727 38 611 16 63 -1 611
503.508 42 1023 16 63 -1 1023
? 15 reserved
*Size calculated by # cylinders * # heads * # sectors * 512 bytes/sector
Type 23 seems to work perfectly with my 64 Mb Compact compact flash (from an old Cisco router), though it leaves a couple Mb unallocated. 64Mb does feel a bit small, but it's contemporary with the machine's age.
How you do this is: connect the compact flash, select number in BIOS, go into DOS, FDISK and make the partition (it will select the maximum size equal to what it says in the above table), FORMAT it, and it will work (and can also be removed and read in a modern machine). Heads/Cylinders/Sectors don't seem to concern the CF cards.
Also, once you have a working CF card, you can make an image of it with dd and make backups.
Update: not all CF cards are created equal! I tried another one and it would not work on type 23, always giving a 1790 - Disk 0 Error on boot, despite being another 64MB card. But, tyoe 29 worked fine.
For what it's worth, I tried all of this and it did not work:
I wanted to keep the original Conner drive too since it makes a cool old hard drive sound, and it still works. The original 3.5" drive is mounted in an adapter which fits it to the 5.25" bay (and with rubber mounts no less, even though the Conner drive already has some in the drive). My solution was to push the 3.5 drive further into the machine to make room for a little shelf on which to also mount one of the CF-IDE adapters that I have acquired a pile of. Mine are a bit unusual because they are meant to fit into a 3.5 drive bay instead of the usual ones that fit into the PC rear IO card area.
I started with a 3D printed mount for the drive, then I installed the CF holder and assembled the machine, and used some calipers to figure out a faceplate. It's unlikely that you will have the same CF adapter, but maybe these CAD files will be a good starting point. The drive holder is modeled solid, but when I printed it, I turned off the top and bottom layers so it would be hollow and lighter weight, and have some air flow.
I have never used QEMU before, but this command worked for running with the CF card on a modern machine. The emulator could even boot from it:
qemu-system-i386 -drive file=/dev/sda,format=raw -fda somefloppydiskimage.img -boot menu=on
and then to change floppy images CTRL+ALT+2 and change floppy0 someotherfloppyimage.img at the prompt, and CTRL+ALT+1 to go back to the emulator screen. I found it will also not boot directly from the floppy image, and you have to use the on-screen boot menu to select that. My CF card appeared as /dev/sda in my linux system.
You can't do everything with this setup - I tired running Windows 3.11 after it had already been set up for the plasma display driver, and it crashed back to the DOS prompt. However, I was able to install Dos just fine, and it's a lot quicker than writing floppy images to disk (especially since I don't have any other machines that use 1.2M disks)
I stumbled across this error when I tired installing Windows the first couple times, but this was alleviated by just following the instructions. The only thing I changed was dumping all the files from the Windows for Workgroups 3.11 disks into a single folder, and dumping the plasma screen drivers right in there with them. You still need to add the plasma = line to the setup.inf file like so:
[display]
;profile = driver, Description of driver, resolution,286gr,logo code, VDD, 386grabber, ega.sys, logo data, optional work section
plasma = 2:plasma.drv, "Compaq Portable Plasma", "100,96,96", 2:cga.2gr, 2:cgalogo.lgo, 2:vddcga.386, 2:plasma.3gr,, 2:cgalogo.rle
I actually have a couple of these machines. I used a combination of parts to build my first one, and I had enough parts to build a second one, minus a working screen. But I had 2 partially working screens. One screen clearly had a driver IC problem, so I felt it was worth swapping some drivers from the heavily burned-in screen to see if it would fix it. It did.
These screens are Matsushita (aka Panasonic) part number MD400F640PD5
Parts I scavenged from the parts screen are: SN751518 - PNP Open Collector outputs, used for Column driver, and SN751506 - Open Drain JFET outputs, used for Row driver
The keyboard on these is a capacitive foam and foil type. However, unlike my other non-working foam and foils, these were in good shape - the foil is intact and not eaten by foam outgassing or whatever. I got a comment on my video which suggests they usually are good.
On one of my keyboards, a few keys were not working, which had me a bit worried. But, upon taking it apart, the foam and foil was fine, just like the other one. The fix was to simply spray some Deoxit on the capacitive pads on the PCB, then wipe all the PCB pads down with a paper towel. Amazingly, this got all keys working again perfectly.