How to expand the C16-memory from 16k to 64k



Warning: You should know what you do! You should know more than the end where the solder-iron is hot! I give no warranties for this instruction and your work!

Ok, let us begin

Remove all cables from the C16, open the case and removethe board from the case.

Remove now the CPU (U2: 8501) and the TED (U1: 8360).

You must remove the old RAM-chips (U5 and U6: 4416). The best way is to cut all pins and resolder each. 

Now you must clean the vias. I use a resolder-tool (pump) for this. I fix the board horizontal, heat the via from one side with the solder-iron and suck the tin from the other side.

After this take two DIL-sockets 18-pins and solder it in the empty places. Don't use the cheapest version of this sockets! Note the mark on the socket and at the board for the right direction.

Now you must cut two wires. One is located on the component side directly under a chip. This is a little bit difficulty, but with a small screwdriver you can do it. Look under U7 (LS257). There is a wire from pin 16 to pin 2. Cut it directly in the near to pin 16. You can use a universal mesurement with resistor-check to check your work.
The other wire is from a fat +5V-wire to pin 14 of U8 (LS257) at the back-side of the board. The cut is easy to do.

Now you must use 2 small wires to connect A14- and A15-adress-signal with U7 and U8 (LS257). Connect pin 26 of U16 (PLA) with pin 2 of U7 (LS257) at the back-side with one wire. Connect pin 7 of U16 (PLA)
with pin 14 of U8 (LS257) at the back-side.

Now plug the new RAM-chips xx464 (64k*4) in the DIL-sockets. Note the mark at the socket and the chip!
Plug the TED and CPU in their sockets. Install the board in the case and connect TV or monitor and
the power supply. Switch on the C16. Now you should see, that you have 64k. Switch the power off, close the C16 and ready!

Instruction 1999 by solder/synergy