Looking for info on STB “Spectradyne CH1 1.0” ISA Cirrus Logic GD5426 TV‑out VGA card

[linoleum]

I recently picked up an unusual ISA VGA card and I’m hoping someone here might recognize it or have documentation, drivers, or background info.

Card details

• Manufacturer: STB Systems
• Silkscreen: SPECTRADYNE CH1 1.0
• PCB marking: 1X0‑0228‑402
• Copyright: 1993 STB Systems Inc.
• Chipset: Cirrus Logic CL‑GD5426‑80QC‑A
• Outputs: VGA, S‑Video, COAX (RF footprint present)
• Assembly date: 26/94 (Mexico)
• BIOS: Mentions STB NTSC VGA rev 2.06, IBM, and AWARD — very odd combination

Photos of the card (you may have seen it floating around on eBay)


What I’ve discovered so far:

• S‑Video output works perfectly under DOS (tested DOS prompt, Doom, Wolf3D, Links386).
• VGA output goes mostly blank after TV‑out is activated — sometimes I only get a blinking cursor at the top of the screen, which looks like the card is switching to 15 kHz TV timing.
• The card is correctly detected as a CL‑GD5426 by NSSI and UniVBE.

One interesting quirk:
When launching Direct Access 5, the PCX splash screen causes the VGA output to briefly show the previous text mode (in this case the DA5 menu). This is the only time I’ve seen VGA come back while TV‑out is active. Very strange, but it proves the VGA DAC path is functional.

What I’m looking for:

• Any documentation or OEM manuals mentioning Spectradyne CH1
• STB driver disks that might include TV‑out utilities
• Information on whether this card supports simultaneous VGA + TV, or if it’s strictly one‑output‑at‑a‑time
• Any historical context about this specific STB multimedia line or OEM bundles that used it
• Or just some ideas on what to test on this card!

This seems to be a pretty obscure early‑90s multimedia card, and I haven’t found any references to it in the usual STB or Cirrus archives.

Thanks!

 

[Plasma]

It appears to be a custom video card manufactured by STB for Spectradyne, Inc. It is briefly mentioned in this patent. Basically it was part of a computer system that enabled hotel guests to make purchases via the room phone + TV.

 

[linoleum]

It appears to be a custom video card manufactured by STB for Spectradyne, Inc. It is briefly mentioned in this patent. Basically it was part of a computer system that enabled hotel guests to make purchases via the room phone + TV.

Wow thanks! This is very funny! Anyways, getting my first TV‑out card back in 1999 with my Voodoo3 felt absolutely heaven‑sent. I’m sure I’ll find something fun to do with this one in a nice 386 build.

 

[Plasma]

Anyways, getting my first TV‑out card back in 1999 with my Voodoo3 felt absolutely heaven‑sent.

The TV/PC relationship is interesting. All the 8-bit home computers could connect to TVs. But after CGA, TV-out was no longer expected. There were technical reasons for this of course, but it's still funny that we considered TV-out a "special feature" in the 90s and early 2000s when it was standard in the 80s. And now we've come full circle with HDMI; just about any PC can plug into a modern TV.