PlayStation models

The original Japanese launch model (SCPH-1000), released on 3 December 1994, was the only model to feature an S-Video port. All subsequent models removed the S-Video port and incorporated revised internals. This led to a discrepancy in model numbers between Japanese units and launch units in other regions. The part numbers of launch units released in the US and Europe used the same numbering (SCPH-100x) as the Japanese launch units, but had different hardware (Rev. B silicon and no S-Video port). The hardware was equivalent to the revised Japanese SCPH-3000 model; had their numbering been consistent, they would have been SCPH-3001 and SCPH-3002. Inconsistent numbering was also used for Net Yaroze machines, which were based on SCPH-5000 and later 1001/1002 hardware, but numbered DTL-H3000, DTL-H3001, and DTL-H3002. Early machines were known for having issues with their CD drives. The original optical pickup sled (KSM-440AAM) was made of thermoplastic and positioned too close to the power supply. This caused uneven wear, which made the laser misalign with the disc surface. Later, the KSM-440ACM drives solved this problem by using a die-cast sled with hard nylon inserts. The original hardware design used dual-ported VRAM for graphics memory. However, due to a parts shortage, Sony redesigned the GPU to use SGRAM, which could simulate dual-porting by utilizing two banks. At the same time, the GPU was upgraded to support smoother shading, improving image quality compared to earlier models that were more prone to banding. Transparency effects were also enhanced, reducing slowdowns in scenes that heavily used them. This updated Rev. C hardware was introduced in late 1995. Unlike in Japan, the revision didn't receive a model number change in NTSC-U/C and PAL regions. Both SCPH-1001 and SCPH-1002 systems could have either revision, as the change occurred between revisions of the PU-8 mainboard. The PAL region consoles from SCPH-1002 up to SCPH-5552 were different from the systems released in other regions in that they had a different menu design; a grey blocked background with square icons for the Memory Card (an icon showing a PlayStation with 2 memory cards inserted) and CD player (an icon with musical keyboards) menus. 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. With the release of the SCPH-5000/5003 series being produced only in Japan and Asia, it followed the same exterior design as the Japanese SCPH-3000/3500 series, its only differences being that it was switched to Rev. C hardware (same as late 1001/1002 units) with some upgrades to flawed components from previous models and a reduced retail price. This was followed by the first major consolidation, SCPH-550x/5001 and PAL-exclusive SCPH-5552 units, released in April 1997. This model further addressed the reliability issues with the disc drive assembly by placing the drive further away from the power supply in order to reduce heat; the chipset was also redesigned to use digital servo for focus/tracking and also to auto-calibrate the drive, as opposed to manual gain/bias calibration on earlier models. 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. These were followed by the SCPH-700x and SCPH-750x series, released in April 1998. They are externally identical to the SCPH-500x machines, but have internal changes made to reduce manufacturing costs (for example, the system RAM went from 4 chips to 1, and the CD controller went from 3 chips to 1). In addition, a slight change of the start-up screen was made; the diamond remains unchanged but the font used for Sony Computer and Entertainment is now consistent, making the words appear smaller than the diamond overall, and the trademark symbol is now placed after "Computer Entertainment" instead of after the diamond, as it was on the earlier models. New to the SCPH-700x series was the introduction of the "Sound Scope"light show music visualizations. These were accessible by pressing the Select button while playing any normal audio CD in the system's CD player. While watching these visualizations, players could also add various effects like color cycling or motion blur and can save/load their memory card. These were seen on the SCPH-700x, 750x, 900x, and PS one models. The final revision to the original PlayStation was the SCPH-900x series, released in May 1999. These had the same hardware as the SCPH-750x models, except the parallel port was removed and the size of the PCB is further reduced. The removal of the parallel port is partially due to the fact that Sony did not release an official, consumer-facing add-on for it; it was used for cheat cartridges and software development hardware, and for the parallel port to defeat the regional lockouts and copy protection. The PlayStation Link Cable connection was supported by only a handful of games. The SCPH-900x was the last model to support it, as the Serial I/O port was removed on all PS one models. The PS one, released on 7 July 2000, was originally based on essentially the same hardware as the SCPH-900x; the serial port was removed, the controller/memory card ports moved to the main PCB and the internal power supply replaced with an external 7.5VDC power adapter with the other required power rails being generated internally on the main using a mixture of regulators and DC/DC converters for the various rails. It also incorporated a slightly modified version of the menu design previously used only on PAL consoles. The later revision (still designated as SCPH-10x but with a different PM-41(2) main circuit board) was functionally identical, but reduced manufacturing cost for a last time by moving to more highly integrated chips, namely the replacement of external RAM with on-chip RAM, which both reduced the parts count and allowed the use of smaller and cheaper packages by reducing the number of pins required. ==Debugging units ==

There were also debugging consoles - these were generally in either blue or green cases, although there were some special production units (mostly intended for use as show demo units) that were grey, the same as the retail consoles. The debug units were designed to be as close as possible to retail consoles, so they only had 2 MB of RAM (the developer boards had 8MB) and had standard retail boot ROMs. 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. This was done to allow developers to burn games to CD for testing. A side-effect of this was that most debug consoles would also boot discs from other regions (one notable exception being the later NTSC-J debugs, which only boot Japanese titles), although this was not officially supported. Sony made specific debug consoles for each region, and the TRC (technical requirement checklist) provided by Sony for each region required testing the title on the correct debug stations. 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. A (early Japan market units) or Rev. B (later Japan units, US and Europe) hardware, both using the same GPU with VRAM to store the video data. Later models used Rev. C silicon and SGRAM - although the two chipsets had very similar performance, and Rev. C was explicitly designed with compatibility in mind, they were not identical - the 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. Because this made the two machine types quite significantly different from each other, the developer had to test the title on both machines before submitting. The blue debugs (DTL-H100x, DTL-H110x) had the old silicon and the green ones (DTL-H120x) had the new silicon. ==Net Yaroze==

In 1997, Sony released a version of the PlayStation called the Net Yaroze. It was more expensive than the regular PlayStation ($750 instead of $299 for the original PlayStation) and also harder to obtain as it only came via mail order. It had a matte black finish instead of the usual gray, and most importantly, came with tools and instructions that allowed a user to program PlayStation games and applications without the need for a full development unit, which cost around $5,000 at the time. The Net Yaroze lacked many of the features the full developer suite provided to licensed developers, such as on-demand support and code libraries. Programmers were also limited by the 2 MB of total game space that the Net Yaroze allowed, which was otherwise not an issue for games like Ridge Racer that ran entirely from the system RAM (except for the streamed music tracks). It was unique in that it was the only officially retailed PlayStation with no regional lockout; it would play games from any territory. It would not however play CD-R discs, so it was not possible to create self-booting Yaroze games without a modified PlayStation. ==PS One==

The PS One (officially stylized as PS one and alternatively spelled PSOne and PSone) is a smaller, redesigned version of the original PlayStation platform. and went on to outsell all other consoles throughout the remainder of the year—including Sony's own PlayStation 2. The PS One is fully compatible with all PlayStation software; compatibility with certain peripherals may vary, however. The PS One also had additional changes, including the removal of the parallel and serial ports from the rear of the console, and the removal of a separate reset button (the power button is also labeled as a reset button, executed by double-pressing the switch in quick succession). On 2 January 2002, Sony released a bundle set called the Combo that included a LCD screen attachment (SCPH-131) which was initially offered as a separate attachment for the PS One on 19 September 2000. The screen itself included built-in stereo speakers, volume and brightness controls, passthrough ports for power and AV outputs and had a headphone jack as well as an AV mini jack for connecting camcorders or other devices. ==Comparison of models==

Region codes The last digit of the PlayStation model number denotes the region in which it was sold: • 0 is Japan (Japanese boot ROM, NTSC-J region, NTSC video, 100 V PSU) • 1 is USA/Canada (English boot ROM, NTSC-U/C region, NTSC video, 120 V PSU) • 2 is PAL regions (English boot ROM, PAL region, PAL video, 220-240 V PSU). Sub-models exist differing in bundled accessories: • 2A is Australia. Australian mains cord and composite (RCA) cable. • 2B is United Kingdom and Ireland. BS 1363 domestic mains cord and RF modulator instead of composite cable. • 2C is for other PAL countries such as the rest of Europe. Europlug mains cord and composite cable plus RCA to SCART adapter. • 3 is Asia (English boot ROM, NTSC-J region, NTSC video, Wide range 110-240 V PSU) Quality of construction Some units, particularly the early 100x models, would be unable to play FMV or music correctly, resulting in skipping or freezing. In more extreme cases the PlayStation would only work correctly when turned onto its side or upside down. The first batch of PlayStations used a KSM-440AAM laser unit whose case and all movable parts were completely made out of plastic. Over time, friction caused the plastic tray to wear out—usually unevenly. 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. Eventually, the tray would become so worn that the laser no longer pointed directly at the CD and games would no longer load. Sony addressed this issue by making the tray out of die-cast metal and additionally placed the laser unit farther away from the power supply on later models of the PlayStation, which also indirectly fixed FMV skipping and freezing issues completely. ==See also==