[spooky]

in answer to you questions.

1. there are only a few mod chips used for PSX (PIC 12c508, 12c509 and 16c84) these numbers will be printed on the chip itself but WILL NOT tell you what Version of code is in them. The Pic series of chips are microcontrollers that can do almost anything you want provided you have the source code available to program them with. The chips also have internal fuses, so if you try to read the infomation (Source code) from them then the fuse will blow rendering the chip usless. So the only way you can find out what version of mod chip you have would be to ask the person who installed or programmed the chip in the first place (If the will tell you).

2. I agree with tif on this one, internal mods are much better, for a start with some of the external devices need to have the original disc to boot from, with an internal mod you dont.

3. It's not that difficult to install your own mod chips.. but use a 15 or 18 watt soldering iron with a very fine tip as some of the solder points are minute, dont use a 25 watt iron as you may end up burning the tracks of the PSX Motherboard. Tin the wires and pads first this will reduce the time the soldering iron is on the board.

the best site for diagrams i have found is www.paulmax.eng.net the diagrams can be trusted as well as the source code also downloadable from this site.

The only other this you will need is a good pic programmer, now you are talking money, £150 for a good one although you can find circuit diags to make you own but i spent £150 three year ago on a PICSTART PLUS DEVELOPMENT KIT for piece of mind.