PS1 Laser Repair.

I'll give it 4 or 5 days before he comes back saying his laser is fried or something

 

The right equipment is not a multimeter, but an oscilloscope/jitter meter.
A lot of guides mention multimeters because that is the only cheap thing that people have out there.

Just look at the earlier PlayStation service manuals. The earlier ones have diagrams for adjusting and testing the CD-ROM subsystem. They do not mention voltages, but show waveforms.

But if I am wrong here, please correct me. We ought to sort out this misconception.

 

Correct equipment is the real test CD, oscilloscope, jitter meter and a manual for the service routine.
You can get away with just the oscilloscope. Optimize the RF pattern with a pressed CD and hope the jitter isn't too bad.
If it was, there's nothing you can do except replacing the optical block anyway.

A multimeter is useless. You could tweak the bias all day and never notice if your RF level was totally off.
At least you can hear it when it's too high. The squealing coils don't sound healthy ;p

Edit:
With PSX drives, I usually find the problem is mechanical anyway.
Taking the drive appart and replacing the old grease often ressurects even the worst examples. Cleaning the turning mirror sometimes improves the RF level by 20%.
The spindle motors are often bad. Replacing those also helps a lot.

 

Rama, I have 2 PSX's that both have iffy lasers (FMV's skip, but ingame loading is fine)
Would greasing the gears and cleaning the mirror help to improve that?

 

Don't attempt to clean the mirror. It requires the right tools and technique to get to it.
But cleaning the slide rails and regreasing them is doable and I recommend trying it.
It's definitely necessary if the old grease is gone, dried out or some other kind of "crusty" ;p
The gears don't need greasing. Typically they work worse if gunked up.

 

Notice any differences between the PU-8-11 (Early US 1995 PU-8 with old GPU) and PU-8-21?
Because i did notice a difference. On the PU-8-11, The SCEA screen will instantly disappear as a Incomplete Startup and when was at the white Sony Logo, It instantly started going to 2x. On the PU-8-21 like i have and up and running, The SCEA is extended. Probably a change of chips from the production line?

 

Today i bought another SCPH-1001 made August 1996 and i noticed it has the more reliable metal KSM-440-ACM lens assembly instead of plastic since it doesn't sit lower. Is the metal ACM reliable the same way as the BAM? As long it has good lubrcation. Mine also has a metal spindle in it.

 

No it's not but couldn't you just purchase a PSOne console or the BAM laser itself and swap it? I mean, the ribbon cables are a direct swap with a SCPH-1001... I successfully desoldered the laser that came with my SCPH-7500 and swapped ribbon cables with the BAM model but not even that is necessary here... Also what I did wasn't even required because I had no clue about the cable extenders.

 

I used a BAM laser in my 1001 and after using that image rama posted it now runs great. I used a mutimeter guide a while back thinking that would work. Glad I didn't go nuts with adjustments just had to dial them back a bit. I'm curious what is that potentiometer that isn't circled used for?

 

Glad it helped
The uncircled pot's use is uncertain, as far as I know.
It affects the ability of the console to read the license wobble. Too far on either side, and original games do not boot on unmodified consoles anymore.
I could not detect any other effect and thus I believe it is solely for the wobble detector.

 

I have an SCPH-1001 from August 1995 that i accidentally touched the BIAS AND GAIN pots on. It's the one with the pots from a PU-7 which can be confusing. Here is a picture on what i mean on those type of pots:

Early POT from PU-7/SCPH-1001 PU-8-11


This is the POT of a later SCPH-1001 which is so easy to work on:

What does the green mean? What does the yellow mean? What does the red mean?


Does anyone know the original position where i can reset the older pot on the first picture back to. If you got a picture and mark it with a color. I would apperciate it, because it is working very poorly with very rough skipping.

 

If the position of the pot was the same on all consoles, they wouldnt put a pot there in the first place.