C64 Keyboard Connector to DB-25 Female Connector
Here, you can find the connection schema for C128D like keyboard. This keyboard is used in my tower-64 together with an AT-keyboard. So, you need this information if you want to have a seperate compatible C64 keyboard.
Separate C64 keyboard can be consist of three parts:
For the first part, you can use the keyboard's own cable with its connector, since it's hard to find those connectors. Simply desolder the wires from the keyboard and solder them to the DB-25 connector as described below.
For the third part, you need a 20 line strip cable (actually you only need 18 line but 20 is a standard, and since I'm not a native speaker of this language, I don't know the correct term for this cable, sorry). This cable must be soldered inbetween keyboard and the second DB-25 connector.
There are color codes in original C64 keyboard cables, this may help you for not being confused in wiring. If you follow the schema below, you can end up with a C128D compatible keyboard (without C128 specific keys of course).
Here is the wiring:
C64 MotherBoard Keyboard keyboard pins meaning DB-25 Label Cable Color --------------- ------- ----- -------- ----------- 1 gnd 1 I white 2 not connected 2 3 restore 3 8 black 4 not connected 4 5 r3 5 7 grey 6 r6 6 6 purple 7 r5 7 5 blue 8 r4 8 4 green 9 r7 9 3 yellow 10 r2 10 2 orange 11 r1 11 1 red 12 r0 12 0 brown 13 c0 13 H grey-white 14 c6 14 G purple-white 15 c5 15 F blue-white 16 c4 16 E green-white 17 c3 17 D yellow-white 18 c2 18 C orange-white 19 c1 19 B red-white 20 c7 20 A brown-white
As it's seen above, there is one-to-one connection from pins to DB-25 By the way, to make a keyboard, I cut the C64 case and mounted the connector to the one of the sides. Then I connected this keyboard to the C64-tower with a 3 meters data-switch-box cable. And it works fine.