PSX (mod)chip help...

[tmcw]

Hi, hope someone can provide some guidance.

Have a PSX, got it a few years ago on eBay, was advertised as a PSX, nothing about a modchip or anything, I was only looking for a stock PSX at the time. Anyway, I acquired a PS2 a short time later, so the PSX didn't get much use after that.

FFWD to now, and I was having a look at it, thinking of getting a chip for it, open it up, and see that some work has already been done to it at some stage. Here are the details:

- PSX is a PAL SCPH-7502
- An extra 8 legged chip found under the motherboard
- On it, the number "120508A"
- 3 wires from it going to various points on the motherboard
- Pin 1 goes to a point near L111 (red wire)
- Pin 6 goes to point near a mark "53" (white wire)
- Pin 8 goes to pad CL706 (black wire)
- Pin 5 looks like it had a wire connected at some stage, but is now gone
- Another connection (yellow wire) connects another 2 points on the board

I'm hoping someone might be able to tell me what this chip is? Is it a modchip, or something else? Any good starting points would be great.

Also, should there be more wires wired up? Or would it have some (possibly limited) function as it is? As far as I recall, there were no issues with any retail games I tried. I never tried backups or games from other regions.

Finally, if the chip should be functional as it is, is there any special procedure to make it work, or activate it? Or what should I do to check it out, test it?

I'll be grateful for any helpful pointers. Thanks.

[LopoTRI]

Yes it´s a mod-chip. But if you can´t play backups, then maybe something is damaged....

Your picture is to small, so i can´t see where it is soldered.
Here you can find your model and the different chips for PSX. Take a look...

http://psx-scene.com/forums/f10/coll...72/#post480509 (Collection of wiring diagrams for the PS-One system)

[tmcw]

Thanks for the reply...

Between your link and some images I found on a modchip shop website, it seems like it's a Stealth Classic, but not quite.

The chip in mine has only 3 wires used, so is nearly like the following photo:



Link wire (green) and Pin 6 are the same. Pin 8 is connected elsewhere, but continuity says it's the same spot (actually Pin 8 in the next photo below).

Pin 1 is different though, more like Pin 1 in the photo below, which is how a Stealth 2 would be wired for my SCPH-7502.



I'll keep looking for an explanation as to why this chip might be wired slightly differently, but if anyone has any info to chip in, feel free.

Anyway, I downloaded a few ISOs, burned them, and they are working to an extent. My unit is a PAL, and the PAL ISO I tried worked fine. The two US ISOs I tried also booted up, but are in B&W. Not sure if it's a limitation of the chip, or my TV. Need to pull the TV remote to get into menus, etc., so will see if it's capable of utilising an NTSC signal, which I presume the PSX is trying to output.

Again, if anyone has any good info or ideas, I'd be grateful.

[LopoTRI]

The two US ISOs I tried also booted up, but are in B&W. Not sure if it's a limitation of the chip, or my TV. Need to pull the TV remote to get into menus, etc., so will see if it's capable of utilising an NTSC signal, which I presume the PSX is trying to output.

I have bought a RGB-Cable for years ago, and my TV has 2 "SCART". The 1. SCART-slot can handle RGB, the 2.nd not.
So i connected my PSX with the RGB-Cable in SCART-slot 1 and all games (PAL & import) played in colour...

[tmcw]

Don't have a SCART cable for the PSX, so I was trying a RF cable and a composite cable.

Couldn't get colour with the US ISOs on the newer TV, so I pulled out an old Philips 21" CRT, and it must support NTSC as I'm now getting colour.

Nice result so, have had a chipped PSX in my possession for several years without realising it. The games probably look better on CRT anyway.