Problem with a 50004

[madmax4]

i have a SCPH-50004 chip moded with read disc error problem.
this happened suddenly. i have tried to adjust the laser head using the pots based on some ps2 repair guides from the net. why there isn't any guide for 5000x versions? can i find one?
i don't know where to measure the laser signal on the board with an osciloscope. can anyone help on how to adjust the laser head?
any other help will be appreciated!

[lufcfan]

I'd find a pro if I were you mate to take a look at it. Where abouts are you based?

[madmax4]

i have knowledge on electronics but i'm not a ps2 specialist!
i use "ultimate ps2 repair guide" and i can see some pictures on how to measure the laser signal with an osciloscope.However, the book doesn't include SCPH-5000x versions so i don't know where to measure.Anything that you suggest and covers SCPH-50004?
i want to try all the possible solutions before i change any parts. i.e:laser beam or mod chip.(i supposed that one of these is fault).
But i need some suggestions.
i have also change the angle of laser head to make it totally horizontal(it wasn't) .is it right? any way on how to adjust the angle of laser rather than doing it in blind?

[lufcfan]

It doesn't need to be horizontal - you'll probably find that that will cause more problems, and adjusting the angle of the laser to read both types of media perfectly is a time consuming process, which is why for me it's a last resort. :(