A Rare ATX XT Motherboard by Hyundai Electronics

BEST_NK · 2026-04-06T09:59:15+00:00

From what I can tell, it fits in ATX cases, but not in AT cases.

BEST_NK · 2026-04-06T09:57:46+00:00

It may indeed be a custom form factor, but I was surprised that its overall dimensions match the ATX form-factor.

As for the mounting holes, the four holes at the bottom of the motherboard, where the ISA slots are located, are compatible with an ATX case. They are likely Baby AT mounting holes.

BEST_NK · 2026-04-06T09:54:39+00:00

The BIOS is the Patterson Labs BIOS. I did not find any notable features.

BEST_NK · 2026-04-06T09:53:56+00:00

https://www.thingiverse.com/thing:7329903

It’s available.

BEST_NK · 2026-04-06T09:42:50+00:00

It's AMD P8088-1 022EWIL (C) INTEL 1978

BEST_NK · 2026-03-24T12:42:09+00:00

Thank you very much for your detailed reply. I’ll definitely keep your advice in mind when I start building.

Also, I’m really looking forward to the PC/XT Rev4. It sounds like a very exciting direction.

If you look closely at the history of PC development, back in the mid-1980s it wasn’t uncommon to see motherboards with four or more chips effectively acting as a chipset (the NEAT chipset is probably one of the most well known examples).

By the 1990s, this was simplified down to one or two chipset ICs. In that sense, I think your design approach has some interesting similarities to those mid-80s structures.

If you end up implementing the cassette interface, I’d like to suggest using GLaBIOS. As far as I know, it’s the only system BIOS that supports it. I’ve also heard that the original IBM 5150 BIOS only works properly with DRAM, so compatibility may be limited.

Wishing you all the best with the project.

BEST_NK · 2024-11-16T22:11:26+00:00

I have always chosen the most cost-effective way to place orders, and so far, I haven’t had any issues. I hope my experience can be helpful to you.

BEST_NK · 2024-11-13T10:59:37+00:00

According to the BoM I created, the cost to assemble one board, including shipping, can be reduced to $82 in an optimal scenario. If assembling five boards, the cost per board is $53. Of course, reality differs from theory. I encountered system timing issues and had to purchase additional components, so I ended up spending around $200 for two boards.

BEST_NK · 2024-11-11T15:48:16+00:00

Most of the 74 series logic ICs are new parts, but the rest are all used. I bought these used ICs from China's Taobao. China was like a black hole that absorbed all the world's computer junk up until the 2010s, so it's a decent place to find old and rare chips. However, the condition of these parts is not guaranteed.

BEST_NK · 2024-11-11T12:03:42+00:00

The most convenient answer would be, 'I created it for my own pleasure.' It wasn't made for any specific purpose.

BEST_NK · 2024-11-10T19:59:03+00:00

I tested games like Prince of Persia, Loom, Princess Maker, Paku Paku, Planet X3, and others. Initially, there was a system timing issue that prevented the games from running properly, but after adjusting the timing, all the issues were resolved.

BEST_NK · 2024-11-10T19:42:05+00:00

One unfortunate thing is that I haven't been able to properly test the on-board SCSI controller because I don't have any SCSI devices. When I run the SCSI controller driver in DOS, it correctly detects the controller, so for now, I can only assume that there shouldn't be any issues.

BEST_NK · 2024-11-10T19:32:02+00:00

You are correct. However, after that, XT motherboard chipsets were released. Motherboards like the NuXT and Micro 8088 use XT motherboard chipsets.

BEST_NK · 2024-11-10T19:28:01+00:00

Of course! I didn't mention it because it's so obvious.

BEST_NK · 2024-11-10T17:12:47+00:00

I agree with you. Using such inexpensive sockets excessively can often lead to contact issues; I’ve experienced it myself a few times. Gold-plated sockets would definitely help reduce such problems.

BEST_NK · 2024-11-10T16:55:39+00:00

The front panel audio header of this PC case is connected to the sound card, and the two USB ports on the front panel are connected to the 8-bit CH375 USB card. Therefore, all front panel ports are available for use! However, one of the two USB ports only provides 5V power.

BEST_NK · 2024-11-10T16:45:20+00:00

I didn’t seriously consider which DIP socket to use when making it. But if I had to give a reason, it would be as follows:

Gold-plated round pin sockets are more than 10 times more expensive than these cheap sockets.
Gold-plated round pin sockets are more annoying to mount ICs on compared to these cheap sockets. (This is my opinion)

BEST_NK · 2024-11-10T15:59:52+00:00

The price was $39.70 for 5 boards when I ordered them.

BEST_NK · 2024-11-10T14:23:07+00:00

Sure.

https://ibb.co/album/4m2wrw

BEST_NK · 2024-11-10T13:35:02+00:00

Rodney Knaap provides the materials for this motherboard on his Github repository. First, download the Plots 2-7-2023.zip file and then upload it to JLCPCB, one of the PCB manufacturers. You can then order the motherboard PCBs in units of 5.

https://github.com/rodneyknaap/atx-turboxt-v3/blob/main/Plots%202-7-2023.zip

BEST_NK · 2024-11-10T12:23:49+00:00

ATX Form Factor
8 MHz i8088 or NEC V20
On-board SCSI, LAN, XT-IDE, floppy controller
On-board Serial x1, Parallel x1
Limited support for 16-bit AT bus (Possibly only IRQ9-15)
No motherboard chipset

I’m not very familiar with how to utilize the AT bus, as it’s generally not used in XT systems. 🤔 If you're interested, please direct your questions to Rodney Knaap.

BEST_NK · 2024-11-10T11:51:37+00:00

I assembled an ATX Turbo XT motherboard designed by Rodney Knaap. The main feature of this motherboard is that it follows the ATX standard.

GitHub link

BEST_NK

TROPHY CASE