Managed to get a lung infection again around New Year (at least not Covid like last year). Not great for many things, but keeps me inside and inactive, which is perfect for getting around to messing around with some old hardware that I hadn't properly worked on yet.

Case in point: a nice little pile of so-far anonymous "PT-2072" VLB VGA cards with IIT Xtec AGX16A controllers.

Nice obscure stuff. The card has 1MB of RAM onboard, but ZIP-sockets for 1MB more, and if I read the blurb on these chips correctly they can actually use the extra RAM for more (non-interlaced) video modes. The RAMDAC, a Sierra SC15021CV, is a 24-bit model so should allow it too. Have already sourced some ZIP 256kx4 chips which should arrive in a few weeks.

But, before I can run (2MB modes) I need to walk (1MB modes). This is an old 1993 chip so even though the card seems to be from early 1995 I wasn't expecting native VESA support. And sure enough: none present. So it's UniVBE time. According to readme.txt:

Supported Graphics Chips

[...]

. IIT AGX-010/11, AGX-014, AGX-015, AGX-016, AGX-017

Now, the AGX-016A isn't listed by name, but if a whole range is supported I'd be surprised if one subversion isn't.

But I'm not having any luck. Running UNIVBE.EXE gets me:

No supported SuperVGA chip detected!

Anyone managed to get an AGX of any type to do VESA? Or specifically the AGX016A?

Specs:
- "PT-2072" VLB card with AGX016A and 1MB RAM
- Auva CAM33-P9-like 386/486 board with OPTi 495SX chipset and MRBIOS
- Cyrix Cx486DLC-33
- 16MB RAM
- Goldstar (branded) ISA I/O controller
- GOTEK floppy emulator
- DOS 6.22 bootdisk
- UniVBE 6.7

Edit:
Have seen that my card is virtually identical to the Orchid Celcius, which was mentioned here: Re: Windows drivers for IIT AGX 015/016

The Orchid Celsius VLB driver has an installer that can provide these cards with a functional VESA TSR (including for the AGX-014, though your mileage may vary with the AGX-016 and other variants of the AGX-015), if your card does not have an appropriate BIOS. UniVBE 6.7 then seems to work just fine with these cards, after the TSR is loaded.

You can install the TSR from a menu, and even though the driver installation will warn that the Orchid Celsius isn’t present, you can proceed regardless of the warning.

Proceeding to attach HDD to the system, install DOS on that, then to give this a try.

Edit2:
Those Orchid drivers are a pain. You must have a C-drive in your system. You must run the installer from the A-drive. But once it's finished bullying you into arranging that and you choose the VESA driver, it just dumps a single file into a directory of your choice: CVLBVESA.COM. It's an 8400-byte TSR. So I ran it...

UniVBE 6.7 still doesn't find a supported chip. But... VESA modes do now (partially) work:

VESA 4BPP
- VESA 102 800x600/16: perfect
- VESA 104 1024x768/16: screen looks 'scrolled', bottom 1/4 appears above top. Otherwise fine.

VESA 8BPP
- VESA 100 640x400/256: perfect
- VESA 101 640x480/256: perfect
- VESA 103 800x600/256: perfect
- VESA 105 1024x768/256: perfect

VESA 15/16BPP
- VESA 111 640x480/64K (5:6:5 ): perfect

VESA 24BPP
- VESA 112 640x480/16.8M: no colours, looks like RAMDAC doesn't like 24b after all

VESA TEXT
- all tests failed to put visible text on screen, occasionally showing a "Scrolled down 3 rows!" message.

So, looks usable for DOS stuff, if you can live with the TSR, but no 24b modes out of this card. Best I can hope for with 2MB in that case is 1024x768/64k - which is a pretty usable Windows resolution.

To be continued once I have the ZIPs, then I'll see if the Orchid Celsius drivers will let me run Win3.1 with the card.