PS1 read errors

[BetaWolf47]

So, I managed to buy a THIRD non-working PS1 in a row.

I own an SCPH-7501 that has graphics and sound glitching during gameplay. It always loads fine, however. The glitches go away when I put the system on its side.

Frustrated by that, I bought an SCPH-7001 on craigslist. The unit is physically in fine shape, almost in a near-mint condition. I was assured that the unit worked fine. It doesn't. Games will occasionally crash (so to speak) at loading screens. I confirmed this to be a problem with the laser by putting the laser in the previous system.

Really annoyed at this point, I tracked down an SCPH-9001, which is documented to have an improved laser. Lady at the flea market assured me it had been tested. Bought it home to try. FMVs and music are failing to load. There are grinding noises during loading screens.

What can I do at this point? I have 3 systems and none of them work right. Which would be the easiest laser to fix?

[Polygon]

I don't know anything about the different revisions of the PS1. However, the last one sounds like a gearing issue. Open it up and take a look. It might just need to be greased.

[BetaWolf47]

Where do I apply the grease?

[Gameguy]

You have to take out the laser from the console, open up the plastic case that encloses the laser, and grease the rails. I've previously seen guides online showing how to do this, but I haven't been able to find any now for some reason.

If that still doesn't work you might need to adjust the lasers. There are guides for this online as well.