Fix a 1200 keyboard with a 500 keyboard

[_yak_]

When I was moving my A1200 to an ATX tower I've adapted A500 keyboard for this setup. The signals generated by the A500 keyboard interface can be found on the A1200 mobo. I simply connected them there and it was working flawlessly. However, I used it as an external keyboard so there may be some problems puting it into the A1200 case, there will be problems with A1200 LEDs for sure.

[_yak_]

I forgot to mention that it was long ago and I don't have access to this Amiga now so I cannot provide you with any photos.

However, I've just collected some info found on the www. If you're going to do it then do it at your own risk, I cannot take any responsibility for any damage you may make.

So, the A500 keyboard pinout is listed on Amiga-Hardware site:

http://www.amiga-hardware.com/showhardware.cgi?HARDID=651

All you have to do is to connect the +5V, GND, CLOCK, DATA and RESET lines to the A1200 motherboard. The +5V/GND part is simple. You can get it from diskdrive power connector for example. Make sure you connect it to 5V, not 12V (!) as this would blow up the A500 keyboard controller (and maybe even more).

The other three signals, CLOCK, DATA and RESET, should be called KB_CLOCK, KB_DATA and KB_RESET and can be found on the chip marked U13 (KEYBOARD MPU) on the A1200 motherboard.

Here you can see the chip, it is located near the keyboard connector:

http://www.amiga-hardware.com/download_photos/a1200mb_rev1d4.jpg

The apropriate lines can be seen on the A1200 schematics found here:

http://www.amiga-hardware.com/downloads/a1200schem.lzx (page 9).

Here is the pin assigment (taken from the schematics):

KB_CLOCK - pin 14
KB_DATA - pin 13
KB_RESET - pin 38

If you're good at soldering you can do it yourself. If you're not, better ask someone who is as A1200 is made in SMD technology and the pins are very small.

Good luck!

[_yak_]

Piru may be right, I did it a long time ago so I could forgot that you have to separate the KB_DATA and KB_CLOCK lines from the A1200 KEYBOARD MPU so it does not disturb the transmission.

Of course you don't have to solder to the chip. In fact, I remember soldering it to some other points. Take a multimeter, schematics and see where the signals go, on their way you may find some better place to solder and to cut them.