A500 keyboard on A2000

This is just a quick guide for anybody who wants to use an A500 keyboard on the A2000.

The main problem people have with this is the fact that pressing the ‘ Left amiga , Right amiga and CTRL ‘ keys will not reset the amiga!

To start with the A500 keyboard is designed to be inside the AMIGA and has direct access to the reset line and resets the computer and keyboard at the same time . When this keyboard is attached to the A2000 it cannot do this and just resets the keyboard cpu before it can pass the key presses to the A2000 , so it just resets the keyboard and not the A2000.

Now , to stop it resetting the keyboard , and not the A2000 we just need to make a mod to the keyboard reset circuit so that it does not reset and can pass the keypresses to the A2000. It would also be nice to have at least the power LED lit if not the Drive access LED.

The only schematic for the keyboard contoller that I have found so far is an ASCII drawing.

It is on a thread on the English Amiga Board. Here

I have now found a better schematic on GitHub. Here

The A500 keyboard I have to use is the one with dual ribbons on it for the keyboard membrane.

This is the part that we are interested in is this.

Now to start with I am going to lift the Collector and Emitter of the reset transistor and put a link between the top end of R3 and the top end of R6.

The Collector of the transistor is marked ‘C’ on the board and the Emitter is marked ‘E’.

Now the keyboard will reset the Amiga A2000 and the power LED will light.

The next step is to use the transistor to light the Drive LED to show when a reset ( A+A+CTRL ) is pressed.

I need to link the Collector to the top of R3 and the Emitter to the top of R5.

I have used some heatshrink sleeve to cover the transistor legs to stop them shorting to other components.

Now the Drive led lights ( albeit dimly ) when the reset keys are pressed.

As for the wiring there are plenty of resources on the web for this.

On my keyboard pin one is the black wire and pin 8 is the purple wire.

Keyboard —————- 5pin Din

1. –Keyboard clock— 1.

2. –Keyboard Data— 2.

3. ——–/Reset——- n/c

4. ———-+5v———- 5.

5. —-no cable ( key )—-

6. ———-GND——— 4.

7. Power LED————-

8. Drive LED————–

And now you can use an A500 keyboard on an A2000!!!

These mods are fully reversable , and i have not taken away , or added any components except for three link wires!

If you would like a case to house this project there is one available Here:-

https://www.checkmate1500plus.com/Products.aspx?searchkey=14

It is a bit too expensive for me , but a good quality case to really tidy up this project!

There is also a 3D printable one that i have not tried yet!

https://www.printables.com/model/294898-amiga-keyboard-case/files