PSX Modchip Identification

[causticsoda]

Hi all,

 

I recently purchased a couple of Playstation's on eBay. Turns out they both have modchips, I am looking for some help in identifying what kind of modchips my playstation's have, and also what these chips will allow me to do.

 

First PSX was a PAL 5502 model, the modchip is located on the backside of the psx motherboard

 

Close up of 5502 modchip

 

Second PSX was a PAL 7502 model, this one is located on the front side of the motherboard, and looks like quite a rough job, whoever installed it bent up the shielding to get access to the chips underneath, and left it that way

 

Closeup of 7502 modchip, wire in background seems to link 2 points on motherboard

 

There appears to be Blu-Tak on what I assume(?) is the reset button, any idea what the purpose of that is?

 

These playstation's need a damn good clean out, I think they have been in storage for a long time. I found spiderweb's in one of them!, but they both still work fine.

 

Thanks all for your help!

Edited July 10, 2010 by causticsoda

[+Stephen Moss]

Well the mod chip on the second unit is a one time programable PIC so it could be doing just about anything but the main reason I know of as to why people would mod it is the make it multi region so that they can play games written for say the Japanese market that were never released for the UK so that might by what the mods are but that is just a guess.

[Bruce Tomlin]

They all basically work on the same principle, which is to jam the appropriate code onto the line which carries the detected subcode. Depending on the chip used (PIC vs Z8) there were only a few various programs that people got copies of and would buy their own chips to burn.

 

Theoretically it might be possible to use a chip reader to read the first few bytes of the chip if they're "protected", and that might be enough to identify it. It's really not worth it, though. Normally all you need to know is if the chip is regular, stealth, or "imports only".

[causticsoda]

Thanks stephen and bruce.

 

I tried booting some backup PSX games on the units, and the backups booted on both, so I guess that is what they would be for, should these chips also allow me to play imports?

[R.Cade]

Thanks stephen and bruce.

 

I tried booting some backup PSX games on the units, and the backups booted on both, so I guess that is what they would be for, should these chips also allow me to play imports?

 

Not necessarily- some chips send all 3 region codes, some send only one. Most of them send all three.

[Rex Dart]

I'll add that I installed dozens of various modchips in playstations, and they've always allowed for backup CD-Rs from any region to be run. I've never held a PS1 chip that did one or the other. Not saying they don't exist.

[Bruce Tomlin]

Not necessarily- some chips send all 3 region codes, some send only one. Most of them send all three.

You've got it backwards. They would only need to send all three to work in all regions of consoles, not with all regions of games. And I'm not even sure that would work. Instead, the chip has to be programmed for the region of the console.

 

The copy protection works by a subcode constantly containing SCEA, SCEJ, or SCEE (?) burned into every sector of the disc. The correct code is required by the PS1 to start the game. Chips worked by intercepting this signal and simply spewing whichever one the console wanted. Later it was found that the output from the chip was strong enough to simply override the signal, reducing the number of wires needed.

 

Later, to detect chips, there would be special sectors without the code, and a game would read that. If it did have the code, a chip was being used. This led to the development of "stealth" chips which only sent the code for the first two seconds or so after reset.

 

An "imports only" chip which refuses to run bootlegs works by sniffing the codes coming from the disc. When it sees "SCE", it jams the appropriate next byte onto the line. Since it only changes the region of existing codes, it works with games that detect chips.

 

 

The problem Sony had was in making the region lockout dependent upon the bootleg lockout. If the console could have been region modded with just a switch (like the Saturn), much less effort would have gone into breaking the copy protection.