Thompson Potentiometer (Pot) Adjustment

This is not for the novice, this tutorial assumes a certain level of knowledge and delicacy while working with the components.  As well as the good sense to not plug it in while opened.  Read the warning on the drive.  Do this at your own risk, 

Theory:  The pot on the laser unit itself tells the laser how bright to shine (think of it like a valve on a faucet, the further open the more water flows).  In the case of the DVD drive, the lower the number on the pot the brighter the laser shines.  The brighter it shines the shorter the life of the laser.  It seems the factory standard number is around 1700 the lowest number recommended to set the laser to 800.  (remember the lower you set the pot the shorter the life of the laser and beyond 800 can damage the media you put in the drive)  There is no one number to set it to for success, it varies from drive to drive I personally shoot for a number around 1000 and tweak from there.

Necessary tools

Phillips #1
2mm standard screw driver (like for glasses)
Torx T10
X-acto knife, and a pic (I have dental pic that works great)
Digital Multimeter (available for $9.99 here)

Start by disassembling your Xbox and removing the DVD drive Tutorital
Open your DVD drive Tutorial

Gain Access to the potentiometer by loosening the bottom circuit board enough so you can get a nearly straight shot at the pot.

For the purposes of this tutorial I have removed the ribbon cables to get better shots of the laser, this is not necessary for adjusting the pot.

Looking at the Pot we see 3 contacts. Position the drive so the single contact is on your left, the one to measure from on the right is the lower one. (you can also use the screw itself in place of the contact on the left, they are the same for our measuring purposes)

Get a measurement to start from, set your Multimeter to 2000 on the impedance setting, looks like little headphones 

Touch points 1 and 3 with the probes, you use red or black with either it makes no difference.  Get an initial reading, it should be over 1400 and not fluctuate.

Scrape away the epoxy on the screw, not always an easy task and probably the most likely chance to irreparably damage your DVD.  The epoxy sticks well and  you need to pick at it hard to get it off, I use an X-Acto knife.  Attempt to slice across the top of the screw until you expose silver across the surface then use a pick to remove the epoxy in the center of the screw.  (while removing this check to see that the contacts are not also covered with epoxy, this happens from time to time and makes it impossible to get a reading)

Now adjust this screw counterclockwise until it reads a lower number (suggest 100 unit increments).  A little goes a long way in adjusting this screw.  After each change completely re-assemble and test the drive.  Repeat until the drive starts working or you reach 800.  If it still does not work at 800 get a new drive.