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Adjusting the Laser Gain............
Adjusting the Laser Gain............ –
I'm certain that there is a tutorial for laser adjustments somewhere, but I thought I might redo one with a picture included.
First of all, let me get a few things clear before you do any adjustments:
* Increasing the laser gain, means decreasing the ohmage. Decreasing the gain, means increasing the ohmage.
Increasing the gain means that it allows more current to flow, which in turn drives the laser harder
* Version 7 machines no NOT need adjustments. The lasers in them are new enough not to require any tweaking, so if you have disk read problems with you mod chip install on these versions, then suspect your installation, the chip or a dirty laser lens. Do adjustments only if the PS2 has had some hard work
* Always measure each pot and note the original settings in ohms before doing any adjustments
* Adjstments should only be slight i.e. approximately 50 ohms each go and should never go more than 150 ohms in total, especially when increasing the gain
* Do NOT go bellow the 650 ohm threashold, otherwise you risk damaging the laser diode or shortening its life dramatically
* Always clean the laser lens with isopropyl alcohol or methelated spirits using a cotton bud before doing any adjustments, as there could be a chance that your disk read problems could be due to dust or other contaminants
Now for the laser adjustments:
First determine what your PS2 boots and what it refuses to boot. i.e. (Example) If it doesn't boot CD or CD-R's, but boots DVD and DVD-R's fine, then you only need to adjust the CD pot. DON'T adjust the other if its booting normally, otherwise your only degrading its life for no reason.
Another point I'd like to make before I continue, is the fact that, if your booting originals ok, but it goes to the red screen of death on backups, then its more likely that its your mod chip and/or poor quality media rather than a need for laser adjustments.
Also, the red screen of death usually means a mod chip problem rather than a weak laser, but there are some exceptions.
Laser adjustments should really be done only when games take ages to load, skipping intros or streaming video and/or sound.
A couple of good games to use for testing streaming problems are GTA3 and GTA: Vice City.
Now, dismantle your PS2 (you should know how to do this) until you expose the bottom of the ROM drve area. Set your multimeter to read 2k ohms (2000 ohms) and place the probes as shown in the picture to measure the CD pot. Don't worry about polarity, as it won't matter which probe is placed where.
Wait for your meter to give a steady reading. Now write the value of your reading on a piece of paper. Do the same for the DVD pot.
If your having problems loading CD media, but ok with DVD media, then just tweak the CD pot. Same goes if your having problems with DVD media, but CD stuff is ok, then adjust the DVD pot only. But if your having problems with both disk formats, then you'll need to adjust both.
Lets adjust the CD pot as our example. Some may find my method awkward, but its more acurate in my opinion:
Using one hand, place the probes onto the CD pot as shown in the picture. You may have to twiddle your fingers a bit to get a reading, but persist and you'll get it eventually. Wait for the reading to steady.
Now with the other hand, adjust the pot with the screwdriver clock-wise very slightly, and lower your reading by approximately 50 ohms.
If your DVD pot needs ajustment, then do the same as above, but on the DVD pot istead of the CD one.
Now partially assemble your PS2. Here's the best way to do it:
This applys to Version 4 machines or higher only, they DON'T apply to earlier versions. I'll explain those further down the page.
Remove the eject/reset switch from the lid of your case and place the lid to one side.
Insert all your ribbon and two pin connectors (V4 only), including the switch bank you just removed from the ROM drive into your motherboard with the heat sink metal work connected with it.
Don't connect your controller/memory port to the motherboard, you don't need it for testing, plus it will only get in the way.
Place the metal work (NOT the expansion bay metal) over your motherboard, but don't screw it together. Just make sure it clicks in with the ROM drive.
Install your fan assembly.
Place the insulation plastic that resides between the metal work and the power supply to where it should go.
Place the power supply over that and connect the mains connector to it.
Now flip the whole lot right side up so you can begin testing.
MAKE SURE YOU DON'T HAVE ANYTHING METALIC OR CONDUCTIVE UNDER THE POWER SUPPLY WHEN YOU FLIP IT OVER. i.e. your bench or table.
Now, connect your mains power and your AV connector to the assembly and begin testing.
Don't leave the unit on in this condition for too long, as it will cause the EE chip and others to overheat, thus shutting down the unit.
If you find you still have booting problems, then disassemble and try lowering the gain another 50 ohms. But before you flip it upsidedown again, be carefull with the power supply, as the main filter capacitor on it is more than likely still charged and will give you a nice zap if your not carefull. Also, make sure you've disconnected the mains lead. DON'T just switch it off at the power point, remove it entirely. Don't take a chance, as mains voltages can kill. You have been warned.
Keep adjusting the offending pot/s until you either get the games to boot ok or you've reached your 150 ohm total. If you find that 150 ohms still doesn't fix your problem, then there's a good chance your laser is on its last legs, so adjusting it further may improve things, but it will definately lessen its life dramatically. I'll leave it up to you if you want to go further.
Now for version 3 and earlier machines:
The great thing with the version 2 & 3 PS2's, is the ease at getting to the laser pots. You only need remove the bottom cover (six screws), the metal sheilding on the expansion bay cage and the motherboard. Then remove the cage and you'll see the laser bottom with the pots on it.
I can't help you with version 1 machines, as I'm not familiar with them.
The early Jap machines (10000 & 15000) require the removal of the ROM drive to get to the pots, but is much easier than V4's and above.
If your adjustments prove successful, then reassemble your PS2 and give it a good flogging. Hopefully you won't encounter any more read problems for a while.
I may have left some things out, but I'm certain that I've covered most bases.