When socketing chips on a Commodore 64 breadbin (250407 board), these are the parts I reach for. All standard through-hole DIL sockets at 2.54mm (0.1") pitch. For which chip is which size on the board itself, see the 250407 visual parts locator.
Machined-pin, not stamped-pin
Always machined-pin sockets, never the cheap stamped-pin (dual-leaf) kind. The stamped sort work, but the contact is a bent leaf-spring against a flat pin. It loosens, it oxidizes, it isn’t a 30-year part. Machined-pin sockets have a turned barrel that grips the chip lead all the way around; the chip seats with a positive feel and the contact stays gas-tight. The whole point of socketing is that you might pull this same chip again decades from now, so buy the socket that’ll be there for it.
The trade-off: machined-pin sockets are less forgiving on insertion than stamped-pin. The barrel grips firmly enough that a pin off-axis by even a millimeter will fold under the chip instead of dropping into the hole, and you won’t necessarily notice. That happened to me on a Kaypro II hex inverter that I was sure had failed, two weeks of debugging for a pin that was bent flat under the chip the whole time. The Kaypro wasn’t even a machined-pin socket; the same mistake on a machined-pin socket is at least as easy to make. Inspect every pin before you push the chip down, and look at it from two angles.
DIP sockets
The four DIP sizes you’ll use on a 250407, with the count you’d buy if you were socketing every interesting chip on the board:
- 4 × 40-pin DIL (15.24mm row spacing) —
Mouser part
649-DILB40P223TLF, FCI manufacturer partDILB40P-223TXX - 2 × 28-pin DIL (15.24mm row spacing) —
Mouser part
649-DILB28P223TLF, FCI manufacturer partDILB28P-223TXX - 3 × 24-pin DIL (15.24mm row spacing) —
Mouser part
517-4824-6000-CP, 3M manufacturer part4824-6000-CP - 8 × 16-pin DIL (7.62mm row spacing) —
Mouser part
517-4816-3000-CP, 3M manufacturer part4816-3000-CP
2114 color SRAM (U6)
The C64’s color SRAM at U6 is a 2114-class part. The original Commodore unit is marked MN 2114-2 (Matsushita); modern second-source equivalents from any manufacturer that still makes 2114s will work.
2114 family background covers the variants and second-source equivalents.