Dell E7440 turns on for 10-15 seconds then turns off

[Zilicon]

Re: Dell E7440 turns on for 10-15 seconds then turns off

It was the original issue and it would not start even after changing the CMOS battery. Like as if the BIOS "forgot" its stuff when the CMOS battery died. I reflashed the BIOS and then it started to boot properly.
But then it died again after not using it for a while, and the CMOS battery is fine at 3V this time. I believe it should start even without the CMOS battery, just taking longer to boot, but this one doesn't and the LED pattern is always the same, with or without the CMOS battery.
The charger is tested fine, and there are no shorts on the mobo. Looks like some some "Management Engine" related shite that fails on powerup.
Does the BIOS at U7 control the boot process? I haven't flashed that one.

PinGuy what's the update?

[Zilicon]

DELL E7440 NO POWER VOLTAGE IS OK. WHEN I PRESS POWER BUTTON JUST LIGHT ON POWER BUTTON LED FOR 15 SECONDS
I HAVE SAME ISSUE MORE THAN 10 PIECES

Magnusa2 it will be good to start another thread stating the problem. Avoid using upper case

[Magnusa2]

Magnusa2 it will be good to start another thread stating the problem. Avoid using upper case

ok

[Zilicon]

ok

With that being said. I think the problem is from the BIOS.
Fetch a confirmed working BIOS and write it on the chip. remember to make a backup,

[Magnusa2]

With that being said. I think the problem is from the BIOS.
Fetch a confirmed working BIOS and write it on the chip. remember to make a backup,

allready did

[mon2]

Continue to measure the voltage to ground on the mosfet @ PQ700 (source / gate / drain pins to ground). Post each measurement.

Also interested in the voltages on PU700 for:

VCC (pin #20)
ACDET (pin #6)
BQ24715_REGN (pin #16)
ACOK (pin #5)

[Magnusa2]

Continue to measure the voltage to ground on the mosfet @ PQ700 (source / gate / drain pins to ground). Post each measurement.

Also interested in the voltages on PU700 for:

VCC (pin #20)
ACDET (pin #6)
BQ24715_REGN (pin #16)
ACOK (pin #5)

PQ700 S = 19.4v D = 1904v G = 0
PU700,, pin20 = 19.3v ,, pin 6 = 3.1v ,, pin 16 = 6v ,, pin 5 = 3.2v

[mon2]

These are good measurements. The referenced p-channel mosfet is being enabled to power the logic board. Are these measurements after 15 seconds?

Do test after the power led goes off after 15 seconds. Also check the voltage to ground of each onboard inductor. Report any low or odd voltage measurement. This can mean a short on that power rail. Be careful since power is on.

[Magnusa2]

These are good measurements. The referenced p-channel mosfet is being enabled to power the logic board. Are these measurements after 15 seconds?

Do test after the power led goes off after 15 seconds. Also check the voltage to ground of each onboard inductor. Report any low or odd voltage measurement. This can mean a short on that power rail. Be careful since power is on.

sorry sir idid't get time today .i will inform you latter