[Wiki] Tatung TCS-5000 Datacomp DFK-700F2 - Futaba MA41

[snuci]

Here's a keyboard that was recently posted on the wiki at [wiki]Tatung TCS-5000[/wiki]. The Tatung TCS-5000 Personal Computer was an IBM PC compatible that had a Datacomp DFK-700F2 keyboard with Futaba MA41 key switches. Sadly, the keyboard tombstone-style key caps have yellowed and the switch plate is a little rusty but it's a very nice feeling keyboard otherwise. You'll notice some specialized keyboard labels. This computer was mated with an IBM 5364 System/36 desktop computer. Some pics are below but more pics are in the wiki.

[Chyros]

Nice! I have an unbranded version of this, although it doesn't work.

[Daniel Beardsmore]

I'm guessing that the disturbingly bright cyan one is MA42 — it should be 33% heavier if it is. MA42 is supposedly linear — is the cyan switch linear or clicky? I've never heard anything about the space bar switch being linear, though.

I wonder why space bar is cyan on some keyboards and grey on others.

[snuci]

I'm guessing that the disturbingly bright cyan one is MA42 — it should be 33% heavier if it is. MA42 is supposedly linear — is the cyan switch linear or clicky? I've never heard anything about the space bar switch being linear, though.

So here's the weird thing about these switches. First off,the cyan switch is clicky as are the white ones but the white ones do NOT click on the downstroke.They click on the up stroke. The cyan switch clicks both on the down stroke and the up stroke. It is definitely different. I am also certain the cyan switch is heavier but I don't know by how much.

Chyros, if you get a chance to try out the switches, see if you can reproduce what I'm experiencing.

[Chyros]

I'm guessing that the disturbingly bright cyan one is MA42 — it should be 33% heavier if it is. MA42 is supposedly linear — is the cyan switch linear or clicky? I've never heard anything about the space bar switch being linear, though.

So here's the weird thing about these switches. First off,the cyan switch is clicky as are the white ones but the white ones do NOT click on the downstroke.They click on the up stroke. The cyan switch clicks both on the down stroke and the up stroke. It is definitely different. I am also certain the cyan switch is heavier but I don't know by how much.

Chyros, if you get a chance to try out the switches, see if you can reproduce what I'm experiencing.

Yes, mine does it too - this is a well-documented phenomenon for MA41 switches. Someone reported that this is because of a rubber part on the inside warping and pushing the click leaf in such a position that it's no longer particularly tactile or clicky on the downstroke, but only on the upstroke, which is presumably what caused these switches to gain a relatively bad reputation. Apparently you can restore them by pushing on them really hard or something but I don't really understand the procedure properly and I haven't been able to reproduce it.

The spacebar switch on mine is grey, by the way.

[Daniel Beardsmore]

This is what it literally says:

. Operating System | * MA41: Non lock Tactile feed-back | * MA42: Non lock |. Rate : DC5V, 5mA |. Operating : 60+/-25gf/80+/-25gf |. Stoke : 3.8+/-0.5mm |. Contact Position | * Pertravel 0.8mm or more | * Overtravel 0.7mm or more |. Life : 50,000 x 10*3cycles Min. |. Chattering | * Initial : 5mS or less | * Life End : 5mS or less |. Contract Resistance | * Initial : 100m or less | * Life End : 5 or less |. Mounting Pitch : 19.05mm |. Specification No. : FS-6015A4 / FS-6016A4

MA41,MA42 , Various Switches
http://www.epartshub.com/company/compan ... &parentCd=

I don't know what the asterisks mean, but they seem to indicate pairs of data, and there's nothing of the sort given for the operating force, either here or for MA71/MA72 (the illuminated version).

You can interpret this two ways: that MA41 is tactile and lighter and MA42 is linear and heavier, or that both weights apply to both types, i.e. MA41 is tactile and MA42 is linear and both types each have heavy and light weights.

MA41 and MA42 aren't part numbers, they're sub-series. MA41JF for example is a known part number, but there's no picture or any other details to go along with it.

It's very clear that there is a linear version, and if the space bar switches don't fit MA41 or MA42 as I understood the spec, then maybe my understanding is wrong.

And yes, they're taunting me with the actual Futaba spec numbers, but I can't obtain them!

[snuci]

Nice! I have an unbranded version of this, although it doesn't work.

Further to this, I tried this keyboard out last night on an IBM 5150 PC and an IBM 5170 AT and both modes work fine when switched. However, if I convert the DIN to PS/2 and then go PS/2 to USB, it does NOT work. I'll have to confirm my PS/2 to USB converter works (I know i had a bad one but am not sure if this was it) but it acted very strange if I did it this way to USB. Maybe that's what you were experiencing?

I don't think I've ever tried DIN -> PS/2 -> USB before. For those who have tried this, this should work, no?

[Daniel Beardsmore]

I don't think I've ever tried DIN -> PS/2 -> USB before. For those who have tried this, this should work, no?

In theory, yes. I must have done it various times as a number of my old keyboards are AT.

Commercial active converters however are appalling. They're hopelessly finicky and every one will have some keyboard it won't work with (normally whatever it was that you just bought). I have little if any experience with community converters; I have one of those entirely-within-the-cable types, and I discovered last night that it may have come from TechKeys. Whoever it came from, no longer sells it, and there was never any indication of who made it (it looks like maybe something orihalcon supplied). That may be my only community converter; I've barely used it but it's worked OK so far I guess?

I just try different converters until I find one that actually works.