PlayStation (console) - Variants

Variants

The PlayStation went through a number of variants during its production run, each accompanied by a change in the part number. From an external perspective, the most notable change was the gradual reduction in the number of external connectors on the unit. This started very early on—the original Japanese launch units (SCPH-1000) had an S-Video port, which was removed on the next release. This also led to the strange situation where the US and European launch units had the same part number series (SCPH-100x) as the Japanese launch units, but had different hardware (Rev. C silicon and no S-Video port)—they were the same as the Japanese SCPH-3000, so for consistency should have been SCPH-3001 and SCPH-3002 (this numbering was used for the Yaroze machines, which were based on the same hardware and numbered DTL-H3000, DTL-H3001, and DTL-H3002). Also, the first models (DTL-H1000, DTL-H1001, DTL-H1002) had some problems with printf function and developers had to use another function instead. This series of machines had a reputation for CD drive problems—the optical pickup sled was made of thermoplastic, and eventually developed wear spots that moved the laser into a position where it was no longer parallel with the CD surface—a modification was made that replaced the sled with a die-cast one with hard nylon inserts, which corrected the problem.

SCPH-100x models are notable for being sought after and modded by audiophile enthusiasts, because most consoles from this line featured a DAC by Ashahi Kasei Microsystems (AKM) and had RCA output.

With the release of the next series (SCPH-500x), the numbers moved back into sync. A number of changes were made to the unit internally (CD drive relocated, shielding simplified, PSU wiring simplified) and the RCA jacks and RFU power connectors were removed from the rear panel. This series also contained the SCPH-550x and SCPH-555x units, but these appear to have been bundle changes rather than actual hardware revisions. Starting with this series, PAL variants had the "power" and "open" buttons changed from text to symbols and the printed text on the back was changed to reliefs of the same.

These were followed by the SCPH-700x and SCPH-750x series—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). A slight change of the startup screen was made. The diamond is seen as longer and thinner and the trademark symbol (™) is now placed after "Computer Entertainment" instead of after the diamond, as it was on the earlier models. Also new to the SCPH-7xxx 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. These music visualizations were kept in all future PlayStation 1 models.

The final revision to the original PlayStation was the SCPH-900x series—these had the same hardware as the SCPH-750x machines with the exception of the removal of the parallel port and a slight reduction in the size of the PCB. The removal of the parallel port was probably partly because no official add-on had ever been released for it, and partly because it was being used to connect cheat cartridges that could be used to defeat the regional lockouts and copy protection.

The PSone was based on essentially the same hardware as the SCPH-900x, but had the serial port removed, the controller / memory card ports moved to the main PCB and the power supply replaced with an AC/DC converter that was also on the main PCB. Also the overall system menu received a graphical overhaul, along with a surround sound/echo effect being added to the CD player menu.

Earliest series had potentiometers on the board for adjusting the reading mechanism, named BIAS, GAIN and an unknown one. By connecting a voltmeter between the upper-most metering point near the BIAS potentiometer and the chassis, the resulting voltage could be read. The supposed right values are 1.70 V when a CD is spinning at 1x speed and 1.85 V when a CD is spinning at 2x speed. Further tuning was also possible on the unique potentiometer present on the CD drive. Later series featured an automatic laser calibration mechanism.

Another version that was colored blue (as opposed to regular console units that were grey in color) was available to game developers and select press. Later versions of this were colored green—on a technical level, these units were almost identical to the retail units, but had a different CD controller in them that did not require the region code found on all pressed disks, since they were intended to be used with CD-R media for debugging. This also allowed the use of discs from different regions, but this was not officially supported; different debug stations existed for each region. The two different color cases were not cosmetic—the original blue debug station (DTL-H100x, DTL-H110x) contained "Revision B" silicon, the same as the early retail units (these units had silicon errata that needed software workarounds), the green units (DTL-H120x) had Rev. C hardware. As part of the required tests, the user had to test the title on both. Contrary to popular belief, the RAM was the same as the retail units at 2 MB. The firmware was nearly identical—the only significant change was that debug prints got sent to the serial port if the title did not open it for communications—this used a DTL-H3050 serial cable (the same as the one used for the Yaroze).