Hello all, my introduction to this forums was quite informational, I was surprised at the depth of information I was able to find for other problems, but no (exact) information ws available on this particular problem.

I am a local computer technician, and I have been working on this clients computer for several days now, and the problem is driving me bonkers . Not that I wasn't before, but that's besides the point.

Situation:
Customer complained of having a faulty power cord, but upon further inspection, the power cord was fine, but the power jack inside the laptop case (Dell Inspiron 5150) had broken of two connectors and was faulty.
Took apart the computer very carefully as per the norm, had it all sectioned out, and found the bad power jack.
Soldered a new one in place, and figured it was good to go.
After putting it all back together, I attempted (note that word) to turn it on to prove that it was working normally.
Nothing....
Well, I checked with and without the battery, and with and without the Power Adapter.
Battery/Adapter in: The LED for Battery blinks orange a couple times indicating that there isn't enough battery power to start the laptop.
Battery in/Adapter out: Nothing happens at all
Adapter in/Battery out: When plugging in the adapter, for a brief second, the Power and Battery LED flash green, and then nothing happens, even after pressing the power button.
After this all happened, I took it apart again, to make sure everything was in it's proper place, and it all was.
I checked the Power Adapter by using a Plug voltage monitor, it's pulling power.
I used a adapter that we have in the office with multiple heads on it, with enough Volt/Amp to carry the laptop specs, and that has same results as the customer's power cord.
I have checked the RAM incase there was a problem there (without working RAM, won't turn on). It was a longshot fix, but not surprisingly , it didn't work.
And then, I used a fully charged battery of the same make/model, AND IT BOOTS UP.

My guess is Bad motherboard (bad circuitry in between the AC input and battery intake)
If anybody here can shed some light on the (troublesome) situation, I would be most appreciative.

Ja Ne!
Rauchster.

Greetings Rauchster

I wonder if you are getting a short somewhere and computer is kicking out a breaker on AC ?

Found this on 5150's



Maybe a crack in the motherboard on or near the power jack?
With 6- to 8-layers and fine trace pitch of modern PCBs, it would be easy for a narrow inner trace to blow like a fuse, very difficult to find.

As a side note there was a Lawsuit concerning this model for power issues a few years ago. Law suit link
But you are at least a year too late.

Looks like a mb replacement in this computers future.

Regards

Kaz.

Hi, i have the same problem.
Battery won't charge at all.
With the AC adapter connected and the Battery removed the laptop does not boot up and the power led and battery led flashes every 7 seconds.
When i insert the battery, the leds stops flashing but the laptop does not power on the same.
With a charged battery the laptop should boot.

Studing the charging circuit i discovered that this circuit is not activated by the MB logic. The core of the charghing circuit is the fujitsu 3887 smd. The CS on pin 22 is ever on 0V. should be +5v.

Looking around i discovered a short circuit on the +5V generated by the max1632 (dc/dc). Due to this short , the leds flashes because the IC is restarted every time the short is detected. i think.
i am not able till now to find the short and remove it but in my case seems to be on the +5v side.
The inductor on +5V became hot after some minute and so i think there is a short somewhere.
If i connect the battery the short seems to be reduced. the inductor is not so hot anche the max1632 in not restarted everytime.
So may be that with a charged battery the laptop should work even if the problem is till present and so dangerous.

i'm investigating yet the problem.
let me know if you have some useful tips.
all my test are now done with the MB removed from the laptop case.


i hope my english is fine.
regards.

Fujitsu 3887 Pin 20 should control "on" "off" function of an insulated gate P-ch FET VFET simular to Vishay Si4435DY. Drain of this FET should connect to Power Adapter Voltage and and the Source should connect to the battery positive after filtering and voltage protection circuits used for hot swap protection. The output of pin 20 should be analog waveform from an internal operational driver amplifier. The pin 22 CS has internal connections to a voltage reference and should only have an external bypass capicator. Internal connected to this pin 22 is a 10 uA constant current source - ie pin 22 is an output if I read the diagram correctly. I would look for a problem with the Power FET...
Pin 18 is a control voltage AND this works on my defective board.... it indicates charging in Windows XP Battery Status... BUT does not charge. I am voting on a defective FET but I will not disassembled the piece of junk anymore today. My attitude is defective for the moment...Need more scotch...