Adapting a Marquardt Military keyboard

[berserkfan]

I'm in the midst of negotiations with another geekhacker to buy his Marquardt Military keyboard.

Shipping to where I am won't be cheap, thanks to the formidable weight.

My main concern is that I want to adapt that keyboard for a regular PCB/plate, but have no idea what could be compatible or what I need to do to make it usable.

This thread suggests that a G80-3000 or a Deck Legend might fit.
http://geekhack.org/index.php?topic=55695.msg1256411#msg1256411

Has anyone tried putting a Deck Legend pcb and plate inside?

[dorkvader]

given their relative scarcity, I doubt it's been tried.

I wonder if it would be better to just get a custom plate made.
 make sure you take advantage of the excellent grounding this case offers.

[berserkfan]

a custom plate also means a custom pcb, right? in that case the cost and possibilities for error will probably skyrocket.

as for grounding, I don't understand how grounding works at all. what is the use of this?

I have been suspecting that my two taken-apart F XTs won't work when I try to put them back because they're shorted or grounded or something, but really have no clue what this is all about.

[dorkvader]

A custom plate does not necessarily mean a custom PCB. I also don't think it will increase the chance for error.

What a custom plate will mean is that the switches will nr held in place and properly attached to the case.

Grounding is a complex subject that I will be happy to discuss in a different topic or via pm once I'm off my phone.

[Tarzan]

Okay, so this thread reminded me I should post pics of my current Marquardt keyboard project. 

This is the stock plate from the keyboard, painted olive drab, with a Cherry G80-3000 PCB below.  [Pay no attention to the switches, they're not soldered in yet - alignments are all crooked.]


As you can see, the stock plate is larger than the G80 PCB on all sides.  This is by design, the plate actually holds the stock PCB to the front or top of the Marquardt case, it's bolted in with about 22 little machine screws.


The G80-3000 seemed like the best donor option (Ivanivanovich's suggestion  ), but I prefer an ANSI layout and the stock PCB and plate are ISO.  And the stock modifier row is kind of funky, as there's only one each Alt, AltGr, and Ctrl, the spaces on the right side of the space bar are for the directional arrows. The number pad is not a usual layout, either.  So basically, I can't use the stock plate without a lot of cutting and butchery, and since the plate suspends the PCB and switches, I don't think it would work out.


What I think I need to complete this project is a custom steel plate with switch cutouts to fit an ANSI G80-3000 layout, but larger than the G80 PCB so I can drill out the requisite mounting holes.  It would be nice to get a new custom plate with the cutouts to allow switch top removal, while I'm at it.  I'm also going to need something to fill the space around the arrow cluster, as that's where the trackball is on the Marquardt version, and some fiddly rewiring/soldering/glueing to fit the LED board to the right place.


As my CAD skills are nonexistent, this is where the project is stalled.  I've been in touch with a couple of folks from the forum about drafting the plate cutting diagram, but I'm waiting for school to get out so people have time in their schedules.  I think it would be nice to get several switch plates made, maybe some in ISO layout too, as there are a lot of people who've acquired these keyboards and donor G80's are pretty cheap. 

These Marquardt cases are beautiful, the machining alone couldn't be replicated for anywhere near what they're selling for on the surplus market.  Bomb-proof, literally.  Best of all, from my point of view, these are full-size keyboards.  So for the cost of a surplus Marquardt, a G80 PCB/switches, and a plate, you're essentially getting a German military style custom full-size keyboard for the less than an assembled GH60.

[berserkfan]

Tarzan

It seems odd to suspend a plate from the top of a casing rather than letting it rest on the bottom like almost everyone else.

what would happen if you tried resting the plate on the bottom, and stabilizing it with something (I don't know, hot glue, or whatever)?

What I am thinking is, I don't like G80-3000 PCB. And I have two Decks (neither of which are actually in the same country with me now! DV has one and Margo has another). Deck Legend casings are plastic and suck. Wouldn't it be better if I could just put a Deck into this casing, then use various cheap-but workable solutions like pieces of wood, foam, or whatever to stabilize the PCB on the bottom of the casing and to raise it near to the top of the casing. That way we don't need to spend money and time making a whole new plate for top mounting.

[Parak]

I'd probably leave the plate alone as long as the holes themselves are MX compatible, and either direct wire the switches or drill new holes in the pcb and wire those up manually.

[False_Dmitry_II]

Are the switches bad? I ask because it seems strange to me to gut something that can, in fact, talk PS/2 and comes complete in order to put MX switches for some reason in there.

[Tarzan]

I'd probably leave the plate alone as long as the holes themselves are MX compatible, and either direct wire the switches or drill new holes in the pcb and wire those up manually.

I'd thought about doing a hard-wired keyboard, but if I'm going to build my "ideal" keyboard, it's going to be ANSI layout.  Plus, I'd rather get a standard layout, to make it easier to swap keycaps.  Trying to find enough new or vintage caps to swap on the Marquardt is a complete PITA, things like a 1x "+" key on the number pad are really hard to source.

Are the switches bad? I ask because it seems strange to me to gut something that can, in fact, talk PS/2 and comes complete in order to put MX switches for some reason in there.

Marquardt switches are... different.  They're not terrible, like Cherry MY switches, but they're not great.  Kind of scratchy, even when lubed, a short throw and a hard bottoming out feel.  I used the Marquardt as my daily driver at work for a couple of months, but when I switched back to a Ducky with MX Clears it was kind of a relief.

Another issue that I never quite resolved is the trackball on the stock keyboard.  From what I've read I think I can make it work using a sort of double PS/2 connector, but so far I've just soldered on a single PS/2 connector for the keyboard.  There are some test results on the DT wiki about the baud rate for the trackball, and what protocol it talks, but that's out of my comfort range.  I need instructions that tell me to "solder the green wire to pin #1," that's more my speed.