Acer Aspire 5750 – 6866 will not turn on

Hi Folks,

This is a troubleshooting entry to help those DIYers and other techs working on this laptop (or one like it.)

Here are some of the symptoms this laptop has exhibited:

• Laptop starts up intermittently (Sometimes will start and go to Windows.  Sometimes will not even POST.)
• Battery will not charge
• Power and battery light flash 5 times
• Power and battery light flash continuously
• Powers on then shuts off 2 seconds later

This laptop has a replacement power supply (Lite-on) and a replacement battery (new Duracell).  After doing some research, I have determined that neither of these replacement parts should cause any of these issues unless they are defective.

Here is what I did to eliminate possible causes and the results in sub bullets below:

• Remove the battery (AC adapter only)
  • intermittently starts up or…
  • starts up and then shuts down after 2 seconds.
• Run with only battery
  • will not start up and…
  • only blinks power light and power indicator on front edge (dead battery)
• Run with both AC and Battery
  • intermittently starts up AND…
  • blinks power indicator, power button (blue) and blinks battery indicator (orange)
• Visually inspected the motherboard without removing power jack connection and power jack connection to the motherboard
• Visually inspected the power jack without removing.
• Changed out the CMOS battery (to no avail)
• Charged overnight
• Discharged overnight and recharge without turning on the power.

None of this worked.

Here is how I finally found the issue.  I completely removed the power jack cable and inspected it.  Though it looked intact from a cursory visual inspection after removing the top panel, the real problem was that the ground wire had become dislodged.  However, it remained in place in such a way that a visual inspection without a continuity test would not find out that the ground wire had become disconnected from the solder point.  So, a technician, doing a visual inspection, would not have found the problem.

I had to completely remove the left speaker, lcd panel and hinges before I could get to the motherboard, disconnect all cables, antennae, and wires, to finally flip it over and remove the motherboard connection to the jack and finally the jack itself from the case which was attached with adhesive tape.  After doing a continuity test and finding that the ground connections were both intermittently working, was I able to check the solder point which was under shrink tubing and thus not visible to reveal the problem.  Also, this created a lot of false positives and could have damaged the motherboard due to power issues.

So, gentle reader… please test the power jack continuity if you have any of the issues above.  Or, you can just replace the power jack and see if that was the cause.