Compatibility of external MSX keyboards thread

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By bateman82

Resident (36)

bateman82's picture

14-11-2012, 15:20

Hi to everyone!
I've just bought a victor hc-95... here's the keyboard connector (20 pin) http://www.geocities.jp/dcc13579/msx1-8.html
Do you think that the philips 8280 can work with it? Do i need an adaptor?
Thanks in advance

By anonymous

incognito ergo sum (116)

anonymous's picture

05-08-2014, 11:30

Hello bateman82. I adapted a Philips keyboard in a Captain NTT (DB25 connector) thanks to the user msxholder and the info shared here. First of all we should know what are the pinout of the HC-95 connector and then try to match pin to pin.

By jltursan

Prophet (2424)

jltursan's picture

14-11-2012, 19:13

First page of this thread Smile

I don't have enough knowledge; but this keyboard seems closer to the HB-F700 one than the Philips.

By Pac

Guardian (6091)

Pac's picture

14-11-2012, 19:19

Ops! you are right Big smile but in case using a Philips keyboard for example, there are different signals,I wouldn't know what to do with de YA, YB, YC signals...

By jltursan

Prophet (2424)

jltursan's picture

14-11-2012, 19:37

That's why I find closer the HB-F700 pinout, they share the same YA-YD signals multiplexed over the X ones. Anyway, I've idea about how to use them... Question

I suposse that Padial is still selling their keyboard carts...

By Pac

Guardian (6091)

Pac's picture

15-11-2012, 19:16

bateman82, quite difficult but, have you tried to find an original loose keyboard?. Do not give up, I think we could adapt other but we need expert comments about which one is more suitable Sony, Philips, etc. What about the Mitsubishi ML-G3 keyboard?.

By bateman82

Resident (36)

bateman82's picture

02-02-2013, 03:11

Hi,
Thank you so much for your answer PAC and jltursan! Please forgive me but I completly forgot about this thread.
The hc-95 has finally arrived and so the troubles!

PAC wrote:

Hello bateman82. I adapted a Philips keyboard in a Captain NTT (DB25 connector) thanks to the user msxholder and the info sahred here. First of all we should know what are the pinout of the HC-95 connector and then try to match pin to pin.

Is it right this hc-95 pin?

msxholder wrote:

duo info 
key board pinning hc-90 hc-95 and HC-95a 

1+2 = +5v
3 =YA
4 =Yb
5 =Yc
6 =Yd
7 =X0
8 =X1
9 =X2
etc
14 =X7
15 =caps led
16 =kana led
17+18+19,20 =gnd

it's strange because mine has this uber rare 20 pin connector:

Do you know if msxholder or manuel are italian?

jltursan wrote:

First page of this thread :)

I don't have enough knowledge; but this keyboard seems closer to the HB-F700 one than the Philips.

Unlucky I don't think that f700 could match
http://old-computers.com/museum/photos/sony_hb700s_front_2.jpg

jltursan wrote:

I suposse that Padial is still selling their keyboard carts...

As i said in the other thread http://www.msx.org/forum/msx-talk/hardware/victorjvc-hc-95?p... I think that padial slot expander it's too expansive :(

PAC wrote:

bateman82, quite difficult but, have you tried to find an original loose keyboard?. Do not give up, I think we could adapt other but we need expert comments about which one is more suitable Sony, Philips, etc. What about the Mitsubishi ML-G3 keyboard?.

Unlucky find a original loose keyboard is quite impossible (there is two hc-95 models: one with the same socket of the philips 9280, the other is mine). I've seen the ml-g3 and I don't think that could match...
http://www.museo8bits.es/fotos/main.php?g2_itemId=171

I post here some writing from my other thread, maybe someone could help me...

bateman82 wrote:

Here' the keyboard pinout of my hc-95:

and here's the keyboard of the 8280:

Do you think I can find a convertor one ebay maybe? Or just soldering a new cable?

Thanks to everyone!

By msxholder

Champion (369)

msxholder's picture

02-02-2013, 10:23

I got both hc 95 pinning is similar !
you need an 74ls145 for decoding 4 line to 10 line or 74ls154 4 line to 16

By jltursan

Prophet (2424)

jltursan's picture

02-02-2013, 13:39

That's it, no other keyboard can match yours as is!. You need to adapt the signals pin-to-pin. I'd mention F700 'cause looks the closest match to the HC-95 one. Keep in mind msxholder advices...

By RetroTechie

Paragon (1563)

RetroTechie's picture

02-02-2013, 14:12

bateman82 wrote:

it's strange because mine has this uber rare 20 pin connector:

Indeed! If you compare with RS232 connector, you'll see that pins are arranged like this:

* * * * * * * *
 * * * * * * *

While on the keyboard connector it's like:

* * * * * * * *
* * * * * * * *

That's very unusual for a sub-D connector; good luck finding one like that. Evil So unless an original keyboard can be found, you'll probably need to bypass that connector & add another one in the back of the casing.

What matters is not what the connector looks like, but what signals are on it & how they're used. If you compare with a few service manuals, you'll find it closely resembles keyboard signalling as used in Sony HB-F700 machines (see page 37 in that service manual). So I think

jltursan wrote:

That's why I find closer the HB-F700 pinout, they share the same YA-YD signals multiplexed over the X ones.

is correct. If you're lucky it's just a wiring job. If not, it might require some logic in between. Question

Finding NMS8250 keyboards is easier, but it would require some sort of decoder that turns 4-bit 'code' XA..XD into a set of 16 (well only 10 or 11 used), where only 1 is active at any time. 74LS145 or 74LS154 you say? Too lazy to check but sounds very possible. These IC's are easy to find & cheap, but Luca would have to figure out how to wire it all up.

Quote:

I suposse that Padial is still selling their keyboard carts...

Not a good option as that would occupy the only available cartridge slot. Crying (and probably expensive too).

Summarized: Philips 82xx keyboards will require electronics in between, are lower build quality but easy to find. Sony HB-F700 keyboard color match the case, are better build quality, and should be easier to connect. I'd go for that if one can be found. A build-like keyboard (read: one that uses same signalling / same connector) like one from HB-G900 or such should be okay too. Note there's different language versions of these keyboards (UK / German / French / Spanish) that have slightly different keys in places (QWERTY vs. QWERTZ for example) - doesn't matter for physical connection, but matters for how easy to use.

In either case there's some DIY coming up, and even some 74xx logic circuitry might be involved. Smile2 On the flip side: you get a 100% free choice on what connector to use for the keyboard (as long as there's enough pins on it).

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