Smooth L7250 chip family
Smooth (L7250 series) chips are in common use. On hard drive controller
boards, they are considered as the "muscle" chip of the
whole hard drive PCB system. Many mechanical & electronic power
functions are governed by this chip, or it's equivalent on other drives.
It has the following main functions:
- Spindle motor driver and speed servo-control
- Head assembly positioning coil driver and servo-control
- To generate a minus signal (usually -5V) power for heads-arm-mounted
preamplifier
Causes of failure
- Electronic failure of chip
- Overstressing of the chip eg. by continuous drive recalibration
or heads spanning / knocking (often due to heads / platter failure)
- On external drives, the same symptom is caused by the spindle
bearing overheating (very common), power surge, or wrong power supply
Other candidates for component failure are often:
- Q500 - FDS2P102A (a double general purpose NPN mosfet) and associated
circuitry
- C508
- CR501
- some ancillary passives
On boards with severe damage, the board power traces (on buried layers)
can blow and even the main chip (Ardent C8-C1, the disk "brain",
can be involved through the serial interface pins used for Smooth
programming.
> Back to the Maxtor
hard disks: Data Recovery section
> Back to the MAIN
data recovery
page
Please note that all modern hard
disk drives are manufactured to very high standards, fail infrequently
and have very similar rates of reliability.
