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Strange problem with HP Compaq 6910

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LAN_403

Chip Fixes

Mon Dec 26 2011, 08:57PM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

I have this laptop:

and it will not start up. But wait there's more! When you take out the battery and reinsert it, it immediately powers on for a approx. 7 seconds (fan spins, power button light is green, the indicator lights for power, wifi, and battery all stay off, cd light is red, screen is unresponsive) then it shuts down and then the fan, power button light, and red cd light, alternate between on and off about every second. this lasts about 5 seconds. When that's done it just stays off. It won't respond when the power button is pressed. Any ideas?

EDIT: I tested the battery with a voltmeter. It's fully charged

The Lightning Stalker

Tue Dec 27 2011, 04:57AM

Registered Member #4230 Joined: Sat Nov 26 2011, 05:50AM
Location: Socketville
Posts: 53

Have you tried powering it from the brick? If that works, then I'm guessing it's a dead battery. Try plugging it in and taking out the battery.

Chip Fixes

Tue Dec 27 2011, 05:55AM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

yeah, it's unresponsive. The battery is fully charged anyway

krenshala

Thu Dec 29 2011, 10:55PM

Registered Member #143 Joined: Sat Feb 11 2006, 04:25PM
Location: Austin TX, NorAm, Sol III
Posts: 28

Find the user/service manual for that model and check for LED POST codes. The blinky lights are most likely giving you at least a hint as to what is happening.

Pulling the battery and running it from power cord only is a good test as well, but it sounds like you've tried that with no change.

When I did notebook support the next step I would usually take would be to pull all customer removable parts (for the ones I worked on that would be hard drive, optical drive, modem, wifi, bluetooth, and memory) and see if the symptoms change. If they do, then the problem is most likely with something that was removed. If they don't change, its probably the motherboard or processor. Normally you get an error when you boot with no memory, but getting that error instead is actually a good thing normally.

If the symptom changed with all that out, start putting parts back one at a time to see when the problem shows up; the last part you put in is almost always the culprit.

Chip Fixes

Fri Dec 30 2011, 07:45AM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

Thanks for the detailed reply! I could only find beep codes and there aren't any beeps... Good idea about removing everything, I did all that and still had the same problem so I think you're right and the CPU/GPU is the problem. I got a very nice Weller soldering iron/heat gun with an adjustable thermostat for Christmas so i'll try a reflow. One question, should I use the heat gun at 200 or 250 Celsius? or a temperature in-between?

Chip Fixes

Tue Jan 24 2012, 10:23PM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

Sorry to bring back this thread but I'm still having trouble. The guy who gave me the laptop gave me $40 to figure out exactly what's wrong and fix it if possible. I found out that no power was getting from the charger to the battery to charge it. So I think the problem lies in the motherboard somewhere... I took the laptop completely apart and tested out the jack with a DMM, it's transferring voltage fine so no problem there. Is there an easier way to figure out what's wrong than checking each component along the path from the jack to the battery?

EDIT: A fried motherboard isn't the answer I'm looking for haha. I'd like to figure out the problem.

Conundrum

Wed Jan 25 2012, 11:09PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

Same problem here, have an HP Compaq which rapidly blinks the power light when you try and power it up.

I did find that "powers up then shuts down" can be caused by a faulty screen cable, seems that it powers on but then something detects the short across the Vcc and shuts everything off again.

Chip Fixes

Thu Jan 26 2012, 01:55AM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

alright well I took the motherboard out of the case and detached everything except the fan (So I could know if it would power up) then plugged in the battery and it did the same thing as usual haha. So definitely a motherboard problem. I'll let you know if I figure anything else out

Conundrum

Thu Jan 26 2012, 06:35PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

Could be BIOS, also I'd have left the speakers connected.

Another "if all else fails" method which has worked for me is to reflow the GPU and chipset with a heat gun.
Ideally using an infrared thermometer to verify reflow temperature is reached, however you can also use a thermocouple from a broken soldering iron element.

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