Compaq 486 Maintenance And Service Manual page 83

13. Using a Torx T-15 screwdriver, remove four screws securing the power
distribution board (Figure 5-27).
14. Carefully pull the I/O cables, diskette drive cable, fixed disk drive
cable, and power cable through their respective slots and remove the
power distribution board (Figure 5-27).
To replace the power distribution board, reverse the steps in the above illustrations.