Commodore 64 (C64C) SRAM replacement
This is a static RAM replacement for C64C chips U10 and U11 (motherboards assy no. 250469).
It may also work on assy no. 250466 (DRAM chips U9 and U10), but I have only tested it on a 250469 board.
It is based on Gerrit4's design, originally posted at the lemon64 forum.
You can use any pin headers you find suitable but I suggest 0.50 mm round pin headers so as not to put too much stress on the sockets. They are easy to find on Aliexpress as "gold round male pin".
You can solder all 36 pins of U10 and U11 as in the pictures below, however only these 23 pins are strictly needed:
- U10: pins 2, 3, 15, 17, 18
- U11: all pins required
For soldering convenience and better board support I suggest soldering the following:
- U10: solder pins 2, 3, 15, 16, 17, 18
- U11: solder all pins
Gerrit4 for the schematic design.