Task: Display Video from an IBM PS/2 Model 30 in HDMI
Needed: ISA VGA Card and OSSC or Similar Upscaler
Time: 30-60 minutes
Introduction
I recently purchased a nice IBM PS/2 Model 30 that was released in 1987 as the first in this line of computers. The original PS/2 came with a 16-bit 8MHz 8086 processor and 640K of RAM. Mine was upgraded by a previous owner to a pin-compatible 16-bit NEC V30 running at 12Mhz along with an 8087 floating point math co-processor. I am really happy to have this machine given its historical significance. Further, I used a 386 PS/2 in grad school in the early 1990s. However, owning IBMs can be annoying given all the proprietary hardware in them that make sourcing parts more difficult today.
One weirdness of the Model 30 is that it uses IBM’s MCGA graphics. I gave up trying to convert this to a signal any of my upscalers and LED monitors could handle and could not find any information online. It seems most people with these machines use an old school VGA CRT (e.g. the IBM 5813) or early LCD monitor that can read the older non-standard MCGA signal. My solution was to put a VGA card in the ISA slot and upscale that signal with an OSSC.
I went with a 16-bit Cirrus Logic CL-GD5401 ISA VGA card with 256KB of video RAM that is backward compatible with my 8-bit ISA bus. The card automatically detects when it is an 8-bit slot an adapts to that architecture. Importantly, this card has its own PhoenixVIEW bios allowing the PS/2 to boot from the video card thus bypassing the problematic MCGA graphics. I picked up this card for $50 on eBay.
Instructions
First, purchase a VGA card compatible with the 8-bit ISA bus. My 16-bit Cirrus Logic CL-GD5401 ISA VGA card works great and ran about $50 on eBay. Other common brands to look for include Paradise, Trident, ATI, and IBM. Verify with the seller that the card is in working order and compatible with an 8-bit ISA slot. Note that you may need to set a jumper to force the 8-bit mode on a 16-bit card.
Here are some searches to try on eBay:
ATI VGA Wonder ISA 8-bit
Paradise PVGA1A ISA VGA
Paradise PVGA1K ISA VGA
Oak OTI-067 ISA VGA
Oak OTI-077 ISA VGA
Trident TVGA8900 ISA VGA 8-bit
Tseng ET3000 ISA VGA
Tseng ET4000AX ISA VGA
Video Seven VEGA VGA ISA
IBM PS/2 Display Adapter ISA
Cirrus Logic CL-GD5401 ISA VGA
Second, insert the VGA card into the ISA slot with the metal tab toward the back. The photo below shows where the ISA slot is on the PS/2 Model 30.
Third, you will need a good upscaler to get the VGA converted to HDMI. I used an OSSC to do this which has VGA in and HDMI out. I purchased a Kaico-branded OSSC for about $170 on Amazon (yes, they are expensive!). Note that the HDMI signal coming out of the OSSC may not be compatible with all monitors. I had trouble with my Arzopa portable LED screens. It worked well with the older Dell monitor shown here and my ViewSonic portable LED that specifically accepts lower frequency signals. My OSSC worked on default settings.
Note that the JideTech I use to convert my classic Mac VGA to HDMI did not work for the PS/2.
Comments
Below are some photos of the upscaled video signal. A nice result and well worth the investment.
