The IBM Model 30 and MCGA proto-VGA (#DOScember)

I take a look at the iconic IBM Model 30, an 8086 machine with a really amazing graphics subsystem.

[qbin]

The repair wires you noticed on the motherboard are usually indicative of a design fix found on early revision logic boards. It's a common practice by manufacturers to run these wires over the surface until a future revision of the board incorporates the fix in the design. This likely means your working PS/2-30 is older than the first. You may be able to confirm with via serial numbers and/or date codes on the computer.

[jasonharmon]

The ones with the white power switch are the model 30-286 machines. All the 8086 ones have red switches. I had one of these with a Sota 386si accelerator card.

[drzeissler]

That thunderstrike look very interesting! thx! I'll give it a try on my A2286/8Mhz/ET4000.

[stevesmusic]

Model 30 Frankenstein! It's Alive! ALIVE!

But seriously, loving your videos

[molivil]

About the HDD issue. Try low-level formatting it with official IBM Diagnostics disk. Many drives after sitting a while lose their calibration, and writing all new tracks helps (or even almost completely resolves) the bad blocks issue. Also, XT-IDE CF ISA hard disks (such as the Lo-tech XT-CF-lite sold at Texelec) pair with these computers well. I'm not sure how long the old proprietary IBM hard disk will work on mine, but I'll use it as long as it runs. Floppy drives are a common issue on these, and there are ways to mod the FDD cable on 286's, but TexElec sells plug-and-play adapters for the model 30 (8086) floppy drives so you can fit standard floppy drives on it. Many owners buy a cheap NEC V20 CPU off second hand market that provides a 50% speed boost for the original model 30's and model 25's. Great video!

[RetroTechChris]

The Model 30 286 has ISA slots as well... also has VGA graphics! I love mine. Memory SIMMS are upgradeable but are nonstandard... they can be modified.

[RamothElectronics]

As the machine has ISA slots you could replace the IBM hard disks with an XT-IDE card and either IDE drives, or a CF adapter. A friend of mine has the Model 30-286 and did exactly that, as his machine didn't have a hard disk.

[temporarilyoffline]

I've never seen one, but it makes sense that if they had a "Model 30 286" that they would have a "Model 30" that is not a 286. Cool find! I had a 30/286 myself, really high quality machine.

[Oosystem]

My first PC, (hated the MCGA not being EGA compatible). Even with the 8086, if you insert a VGA and an Adlib to the isa ports, this machine is great for 80's and early 90's games and software.

[bundesautobahn]

The lower machine must have been bought originally at a store in Austria. But I also noticed a sticker from Deutsche Bundespost in the manual, so I guess that, along with a German MS-DOS, means the computer was meant for sale in Austria, Germany, maybe also Switzerland.

[fatguywitholdcomputers]

gotta love IBM PS/2 machines! Replace the caps on the floppy, it should come back to life. Sadly, that hard drive is NORMAL for these machines. There is a special model of the XT-IDE for the 25/30 and that is the route everyone should take with these systems.

[ropersonline]

4:43: "...that's a high-performance CMOS colour look-up table, whatever that is."

[ACRPC-dot-NET]

With those ISA slots, you have MANY different options for when those hard drives inevitably fail. You can use a modern and inexpensive XTIDE ISA card, or if you want retro, an 8-bit SCSI card (with BIOS) and SCSI hard drives. I went the SCSI route on my Model 25 (8086), 8-bit TMC SCSI card, and a 400MB Seagate SCSI drive. Initially my M25 had an ISA hard card (notoriously unreliable Plus drive) and dual floppies, but I removed one (bad) floppy and installed the SCSI hard drive in that bay. I also installed a network card in the other ISA slot (the M25 only has 2), I can run mTCP stack and get some cool features like FTP for file transfers, and NTP for setting the system clock from the internet, also has IRC, and even Telnet.

[electrohacker]

The capacitors on the floppy druve tend to fail. You have to recap the drive

[ropersonline]

Maybe you could update the description and add #DOScember, in case you want more viewers that way? I'm pretty sure this qualifies.

[kiningroseburg]

I'm not sure if someone else mentioned it earlier in the comments, but you can get an adapter to use a standard floppy drive with the PS2. The floppy drive in the PS2 is notorious for cap failures.

[WaybackTECH]

Ya as others have mentioned those wires were done after the board was etched to fix a design bug or flaw. Very common to see on the old boards from the 80's in general. Some have a snakes nest of wires to bodge fix the problem. You can try to do a low level format in the bios if the bios or IBM utilities have such a function.

[izools]

Really nice comprehensive coverage of the Model 30, thank you. You've managed to make a nice amalgam of the two computers there.

You could do future videos perhaps looking at a Sound Blaster or And Lib upgrade?

[twtube]

I have the MCGA bodge wire in one of my PS/2 model 30 computers, too. It's carrying the vsync signal, and it is just re-routed. The original trace is near the edge of the board and was likely prone to pick up noise or had a problem with reflections. They scratched the original trace close to the point the bodge wire attaches at the big gate array chip and also close to where the trace re-joins the net at the other end.
About that scrolling shooter: VGA has some hardware support for scrolling a playfield with a score bar in the bottom staying at the same position (needs mode X instead of mode 19/13h though to be useful), whereas MCGA is just a stupid framebuffer, so every frame the game has to redraw 60 Kilobytes (as you explain later at 27:30, too). As the MCGA is (like the original IBM VGA) connected to the 8-bit system bus, and not to the 16 bit "local bus" (only RAM and processor go there), drawing 60 Kilobytes is quite slow.

[DxDeksor]

I don't think the lithium battery would have leaked. It's often the varta batteries with nicad batteries that fail that way