CPU (SNES)
The SNES CPU has many revisions of CPU, often labelled CPU-A, CPU-B and so on.
You can interchange all 2-chip CPU's as far as I have tested (although I haven't tested a 1-chip CPU on a 2-chip.
Below are a list of known symptoms I have discovered when repairing that are from a dead CPU.
- Super Gameboy won't load or shows glitched graphics
- Donkey Kong loads initial logo then black screen
- Super Ghouls & Ghosts loads CAPCOM logo, then black screen but audio works
A good test if the CPU or PPU are faulty is to use a Super GameBoy.
If you insert a Super GameBoy of the correct region into the SNES, with a known working game, then turn on, observe the results.
- No / Black Screen > Dead CPU
- Super GameBoy Border but no Game Load > Dead CPU
- Super GameBoy Fully Works > Bad PPUs
Of course no/black screen could be power, video encoder or AV output issus too, or even RAM, but in most cases it is the CPU.
If the Super Gameboy test still didn't work, try inserting Super Ghouls & Ghosts, or Donkey Kong. These games often show the initial CAPCOM or RARE intro screen, then black screen after, if the CPU is bad.
