PPU Chips (SNES)
The SNES has two PPU chips (except on the rare 1 chip variant).
The Picture Processing Unit (PPU) consists of two closely tied IC packages. It contains 64 KB of SRAM for video data, 544 bytes of object attribute memory (OAM) for sprite data, and 256 × 15 bits of color generator RAM (CGRAM) for palette data.
The PPU chip labelled PPU1 is responsible for overlaying typically character sprites as well as other items.
When the PPU1 is faulty you will usually find symptoms such as Super Ghouls & Ghosts will be missing the player sprite but still has the background sprites.
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.