Repair Success Dell XPS M140

[jakdedert]

I'm always a sucker for a bargain, sometimes going way out on a limb
only to watch it be chopped off.

Picked up the above today fairly cheap off Craigslist. Symptom was that
battery wasn't charging, and backlight intermittent (it almost never
worked).

Battery issue turned out to be due to aftermarket power supply. Fixed.

Symptom: backlight came on upon power up, but only lasted a few seconds.
Would again come on after return from hibernate mode. External
display worked fine. Visible image on the internal LCD.

Web research indicated this model had an issue with display, most often
due to a defective magnetic reed switch which signals lid closure.
Diagnostic test for this is to put a small magnet near the location of
the switch and observe. I did that, except I used a hard drive magnet.
Sure enough, the screen lit momentarily, and the machine went into
standby...as if the lid was being closed.

Further experimentation produced longer 'on' times, so I thought I might
be 'on' to something. Sure enough, exercising the reed switch
repeatedly with the powerful hd magnet apparently 'unstuck' the switch,
and it's working fine now.

I wonder if it will last....

jak

 

[hr(bob) [email protected]]

I'm always a sucker for a bargain, sometimes going way out on a limb
only to watch it be chopped off.

Picked up the above today fairly cheap off Craigslist.  Symptom was that
battery wasn't charging, and backlight intermittent (it almost never
worked).

Battery issue turned out to be due to aftermarket power supply.  Fixed.

Symptom: backlight came on upon power up, but only lasted a few seconds.
  Would again come on after return from hibernate mode.  External
display worked fine.  Visible image on the internal LCD.

Web research indicated this model had an issue with display, most often
due to a defective magnetic reed switch which signals lid closure.
Diagnostic test for this is to put a small magnet near the location of
the switch and observe.  I did that, except I used a hard drive magnet.
  Sure enough, the screen lit momentarily, and the machine went into
standby...as if the lid was being closed.

Further experimentation produced longer 'on' times, so I thought I might
be 'on' to something.  Sure enough, exercising the reed switch
repeatedly with the powerful hd magnet apparently 'unstuck' the switch,
and it's working fine now.

I wonder if it will last....

jak

Reed switches are problematic at best. I worked at Bell Labs for many
years, one of our switching systems used reed relays as the actual
switches in the voice path. It was as much an art as a science to
produce reed switches that would hold up for the projected lifetime of
40 years of use. so, keep that magnet handy, you may have to use it
again.