C64 Assembly 250466

• Released in 1986.
• 8-pin board (Reduced Oscillator Circuit).
• Version: B-3.
• Schematic Number 252278.
• Last of the “Bread Bin” Models.
• Identical to previous designs except for the two 64 kilobit × 4 bit DRAM chips that replaced the original eight 64 kilobit × 1 bit ICs.

• CPU : 6510 @ 1.0227277143 MHz (NTSC) / 0.9852484444 MHz (PAL)
• RAM : 64kB DRAM
• ROM : 20kB ROM Total - 8K BASIC, 8K Kernal, 4K Character
• Graphics : VIC-II
• Sound : SID
• Interfaces : 2 Control Ports (CIA U1), A/V, Datasette Port (CIA U1), Expansion Port, Serial IEC (CIA U2), TV RF, User Port (CIA U2)
• Keyboard : 66 Keys (CIA U1)
• Power Supply : External Transformer (9V AC + 5V DC)

Fig. 1: C64 250466 Mainboard Fig. 2: C64 250466 Layout

Cap   -  Value   - Rating - Type
C13   -  10uf    -  25v   - Radial
C19   -  2200uF  -  16v   - Axial
C24   -  22uf    -  25v   - Radial
C88   -  1000uF  -  25v   - Axial
C90   -  470uF   -  25v   - Axial
C91   -  100uF   -  16v   - Radial
C200  -  2.2uF   -  50v   - Radial

C38   -  4.7nf   -   *    - Ceramic

* Replace the 51pf cap with a 4.7nf cap to restore soft-touch RESTORE key function. This is included in our kit.