Most revisions of the PlayStation were made to fix known hardware issues or lower production costs and time, while others featured substantial external changes.

Late KSM-440ACM drives had the sled replaced with a die-cast one with hard nylon inserts in order to address the issue.

The CD player also included reverberation effects unique to those systems until the release of the PS one in 2000, which featured a slightly modified version of the BIOS.

C hardware (same as late 1001/1002 units) with some upgrades to flawed components from previous models and a reduced retail price.

Also, shielding and PSU wiring were simplified, and from the SCPH-5001 on the RCA jacks and RFU power connectors were removed from the rear panel and the printed text on the back was changed to reliefs of the same.

Starting with the SCPH-550x series, PAL variants had the "power" and "open" buttons changed from text to symbols, something that would later appear on the redesigned PS one.

Originally, the PlayStation was supposed to have provision on Video CD support, but this feature was only included on the Asian exclusive SCPH-5903 model.

While watching these visualizations, players could also add various effects like color cycling or motion blur and can save/load their memory card.

The only real difference is that the CD controller was reprogrammed so that it would identify any disc that had a data track as being "licensed", rather than requiring the region code in the lead-in that was present on pressed PlayStation CDs.

The reason for the two different case colors was a hardware change that Sony had made fairly early in the PlayStation production cycle - the original machines were built using Rev.

C version was significantly faster at doing alpha blending, and hence the PS "semitransparent" writing mode - it was also rather slow at certain screen memory block moves (basically, ones involving narrow vertical strips of the display) on top of this there were some minor hardware bugs in the older silicon that had been addressed by including workarounds for them in the libraries - the later library versions checked the GPU type at startup time and disabled the patches if they were not needed.

[citation needed] Programmers were also limited by the 2 MB of total game space that the Net Yaroze allowed.

[4] The amount of space may seem small, but games like Ridge Racer ran entirely from the system RAM (except for the streamed music tracks).

In 2002, Sony released a bundle set called the Combo that included the 5-inch (130 mm) LCD screen attachment (SCPH-131).

SCPH-7000W:Available in Midnight Blue as a promotional item to commemorate the 10 millionth PlayStation sold, this is a Japanese-region console that has a unique BIOS based on the USA NTSC-U/C version that allowed imported games from any region to be played.

The placement of the laser unit close to the power supply accelerated wear because of the additional heat, which made the plastic even more vulnerable to friction.

Sony first addressed the problem by making the tray out of die-cast metal, and additionally also placed the laser unit farther away from the power supply on later models of the PlayStation.

Some units, particularly the early 100x models, would be unable to play FMV or music correctly, resulting in skipping or freezing.