Playstation F-Bias Adjustment

Disclaimer: I cannot be responsible for damages, monetary or otherwise, incurred by the use of this procedure. Anyone who attempts it does so solely at their own risk.

Playstation systems manufactured before December 1995 have a potential problem with their CD drives - the mechanism that moves the reader lens back and forth wears down quite easily, leaving to the lens unable to align properly with the CD. The most noticable result of this is "skipping" in video sequences and music. In extreme cases games will fail to boot altogether.

If a system with these problems is flipped upside down, gravity will realign the lens with the CD properly again, but this is hard on the system. Early Playstation systems have a dial on their motherboard that can be adjusted to bring the lens closer to the CD, temporarily alleviating the video skipping and other problems (until the drive mechanism wears down further, that is). Please be warned that this is a very delicate adjustment, and that a mistake could result in your Playstation becoming totally inoperable. If you still feel reasonably confident, however, read on...

When to attempt this fix
You should attempt this only if your Playstation displays the following symptoms:

  1. FMV sequences skipping on multiple games, even those free of scratches or other defects.
  2. Some games getting only as far as the black boot screen or not booting at all.
  3. The above problems disappear if you turn the Playstation upside down while the games are booting. (This will cause minimal harm to the system, although it shouldn't be done frequently.)

What you'll need

  1. Phillips-head screwdriver

What to do

  1. Find one or more games that will not boot or that have skipping video sequences when run on your Playstation. If necessary try running them now to verify the symptoms.
  2. Remove the five black screws on the underside of the Playstation.
  3. Turn the PS right side up and lift off the top of the plastic housing.
  4. There should be an ribbon of wires (probably orange) connecting the CD drive to the PS's motherboard. Look for a small dial labeled "F BIAS" near the spot this ribbon connects to the motherboard.
  5. Note the dial's current position so that you can return it to its original setting if something goes wrong. Using a screwdriver turn the dial exactly 1/8 turn clockwise (the dial has notches for a small Phillips-head screwdriver).
  6. Replace the system's plastic housing. (It's not necessary to reattach the screws until after testing the games.)
  7. Try booting the problematic games. If they don't run properly reopen the PS and readjust the "F BIAS" dial further clockwise. If that doesn't work return the dial to its original position and consult a repairman. If the games work, congratulations! You've just saved yourself a lot of money.

Unfortunately, even if this fix was a success, it's probably a matter of time before you'll have to start flipping your Playstation over again. The only permanent solution (aside from repairing the drive itself, which would require a great deal of technical skill) would be to replace your system's CD drive - replacement drives are available at

Copyright © 1997-1999 Jay McGavren. All Rights Reserved.