Later fat models
Later Fat Models (SCPH-55xx–9xxx)
As the PlayStation matured, Sony focused relentlessly on reducing the cost of each unit. The later fat models, spanning roughly the SCPH-5500 series up to the SCPH-9000 series, look almost identical to early consoles from the outside but are considerably simpler inside.
Cost Reduction in Action
Each board revision from PU-18 through PU-23 folded more functions into fewer chips. Discrete components gave way to integrated packages, the number of separate parts dropped, and assembly became cheaper. The visible result is the removal of ports: the parallel I/O port disappeared first, and the serial I/O port followed on the very last revisions. By the SCPH-9000 era, the rear of the console was noticeably barer than on an early unit.
Practical Consequences
For modders, these changes cut both ways. Later boards are common and cheap, making them easy to source, but they lack the early ports that supported plug-in import and link devices. Component placement also differs from board to board, so guidance written for one revision may not transfer cleanly.
| Era | Board | Key Change |
|---|---|---|
| Mid | PU-18 | Increased chip integration |
| Late | PU-22 | Parallel port gone, highly integrated |
| Final | PU-23 | Serial port dropped; leanest fat board |
If you want maximum original functionality, choose an early unit; if you simply want a working, affordable console, a later fat model serves well.