NMB Televideo DEC Terminal Keyboard

hellothere · 29 Sep 2021, 20:18

I'm one of the folks that bought a bunch of keyboards in viewtopic.php?f=2&t=25763. I'm creating a new thread just because I don't want to clutter up inozenz's one anymore.

The DEC keyboards are PS/2, but they don't seem to talk properly to a Windows or Mac. If you use an active PS/2 to USB adapter, the keyboard will act like it has a random (I verified) key or two pressed down. If I just use the PS/2 port on my PC, nothing happens. I can't even get to BIOS. I've tried this on two of the keyboards and had the same problem, so I don't think that the keyboards are bad.

I've tried a standard Soarer's Converter and had the same "stuck key" problem. So I did some research ...

* There's a Soarer's WYSE converter listed at viewtopic.php?f=7&t=7424&start=. It looks like it's a standard Soarer's Converter, but needs an extra pull-up resistor ... I think. Before I build one, I wanted to ask if anyone had experience with them. The thread's rather old.

* There's a nice thread at viewtopic.php?f=7&t=19853. I'll shoot snacks an e-mail, but it looks like he had older keyboards (mine are p/n 119857, snacks's are 114178 and 116535). He had to map out a matrix and replace the controller.

soyuz · 29 Sep 2021, 20:18

Once mine come in I'm planning to make a replacement PCB with NKRO if you can sit tight!

Muirium · 29 Sep 2021, 21:27

The stock PCB has limited rollover?

If so then it’s best to replace it outright. Vintage layouts often assumed different user needs than the kind of combos we’ll throw at keyboards today. Model M’s obliviousness to the WASD keys is a famous example.

hellothere · 29 Sep 2021, 23:24

soyuz wrote: 29 Sep 2021, 20:18 Once mine come in I'm planning to make a replacement PCB with NKRO if you can sit tight!

Cool. I'm not terribly interested in having to set up the matrix.

How much do you think you'll sell those for?

TheInverseKey · 30 Sep 2021, 04:08

These keyboards speak an ASCII based protocol so it's best just to wait for the new PCB to be created.

Muirium · 30 Sep 2021, 11:02

Desoldering everything and trashing the PCB is a bit invasive, though. Can’t they be converted more artfully with a controller swap instead?

soyuz · 30 Sep 2021, 12:50

hellothere wrote: 29 Sep 2021, 23:24
soyuz wrote: 29 Sep 2021, 20:18 Once mine come in I'm planning to make a replacement PCB with NKRO if you can sit tight!
Cool. I'm not terribly interested in having to set up the matrix.

How much do you think you'll sell those for?

Depends on what the fabs quote me. It won't be marked up to hell and back though.

hellothere · 02 Oct 2021, 18:44

So, I built a Soarer's WYSEVerter. I tried it first on my new-to-me WYSE 84033801 (WY-60). It worked. I then tried it on the NMB. The converter lit up, but no output from the keyboard. There are two different GND connections on the NMB's PCB and I tried both. Neither made any difference.