Two PAL PS1s: NTSC signal b/w only

[Xan]

So I have two modded PS1s lying here that I finally got around to test, a SCPH-5502 and a SCPH-5552. For some reason on both consoles NTSC games are only output in black and white when using composite. Of course RGB fixes this issue and I don't particularily care about composite, but I'm still curious about this as I can't remember having this issue on other PS1s that I've had for the longest time. Could this be related to the modchip?

On a side note, while the SCPH-5502 holds up really well the laser in that SCPH-5552 seems pretty much shot as it doesn't always read games. So far I've only tried backups and not original games, but still this isn't a good sign. I did clean the lens with some isopropyl alcohol but it didn't help... the previous owner was clearly a smoker and I imagine this might have to do a lot with it. Now I've never fixed any consoles myself, but would it make sense to order a replacement laser and try to fix it without any experience at all, just going by online tutorials?

[Fudoh]

That's normal. On the Playstation the games tell the system in which speed to run. So once you insert a NTSC game you get a 60Hz output, but since the video chip of the console cannot produce a NTSC signal, you get a b/w composite signal. RGB cables have been always been required for modded Playstations.

[Xan]

I did wind up buying a KSM-440ADM replacement part for that SCPH-5552 and it came in yesterday. Installed it, played some Wipeout 3 SE and no issues. Then after a while I returned to it to try another game, but suddenly all I got were some grinding noises and the game wouldn't boot. Upon opening the console again it seems as if the laser pickup is somehow stuck to the spindle... which doesn't spin properly anymore. I would have tried moving the laser manually but a hint on the invoice explicitly suggests against this.

What could have caused this? Anyone have experience with faulty replacement parts? There is some "Hong Lei" logo on the sticker on the box, but interestingly enough it's been blackened with a marker.