msx keyboard changing

Master (179)

10-06-2005, 12:06

hello i have a msx nms 8250 en hb-700p , but i would like to use my sony keyboard at my msx nms 8250. how i can change the connector for my sony keyboard, or the philipskeyboard connector. the reason, the quality of my sony keyboard is much better tehn a philips keyboard. who has a schematics for changing connectors.

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Par NYYRIKKI

Enlighted (6067)

10-06-2005, 12:50

If I remember correctly Phillips keyboard has connector with lots of pins and Sony has only few pins.
So... I think, there is no electronics inside Phillips keyboard, but Sony keyboard must have some kind of keyboard encoder chip.

This means, that it is not just changeing connector, but you also need to add some electronics.

Par BiFi

Enlighted (4348)

10-06-2005, 14:45

Sony also has a lot of pins... only in a different connector. I think it's possible when somebody can make a conversion cable.

Par Manuel

Ascended (19462)

11-06-2005, 12:25

Depends what you mean with 'lots'. The Sony has about 8 pins, the Philips about 26.

Par POISONIC

Paladin (1012)

15-07-2005, 04:24

haha the nms8250 has a small print in the keyboard so if.... the keyboard matrix is the same it could be done but i doubth that

Par Repair-Bas

Paragon (1174)

15-07-2005, 05:57

sony has 13 pins

Par Manuel

Ascended (19462)

15-07-2005, 10:40

13? OK, 8 comes close enough Anyway, much less than the 26 of the Philips, which I actually counted

Par GerhardT

Supporter (6)

15-07-2005, 15:32

Hi all!

Inside the Sony keyboard, there is a circuit with four ICs. The connecter is as following:
Pin2 CAPS LED
Pin3 ... Pin 10 keyboard row
Pin7 ... Pin 10 keyboard column selection (by using flipflop and decoder ICs)
Pin11 switching between column and row
Pin12 +5V
Pin13 GND
Pin1 is not used in the keyboard, but called "KANA" (?) on the mainboard of the computer.

Inside the keyboard of my 8280, there exists no such circuit (there is nothing but some diodes and the keys). Thus, the Philips keyboard needs more lines. 11 separate lines for column selection, 8 lines for the keyboard row, one for CAPS LED and one for +5V. 3 lines are GND, one line is NC. One line "KANA" is not used in the keyboard. Makes 26 lines.

You can find the schematics of the keyboards inside
http://www.funet.fi/pub/msx/mirrors/hanso/service_manuals/philipsnms8280sm.pdf and
http://www.funet.fi/pub/msx/mirrors/hanso/service_manuals/sonyhbf700psm.pdf

You see, compared to the Sony, the NMS communicates with the keyboard in a very different way.
If you really want to use a Sony keyboard on the 8280, you will have to change the circuit inside the Sony Keyboard.
:-(

Regards,
Gerhard

Par Manuel

Ascended (19462)

16-07-2005, 00:26

KANA is for an optional KANA led. The only European MSX computer that has it is the Philips VG-8000/8010, AFAIK.
(Where it is labeled CODE...)