HP Envy 17-j053ea dead. What to look at next?

[rich555]

HP Envy 17-j053ea laptop. The only sign of life is the power LED.

I've taken out the power button and the ribbon to the mainboard that that checks out ok.

No obvious burnt components.

Not sure what to look at next.

The machine was working 100%, switched off, 2 days later, dead.

I've had the memory and motherboard out and reseated all the ribbons and connectors. Still no dice.

I'll check whats on the DC power connector on the motherboard.

Just wondering if there is a hall effect device on the power switch board that detects the lid being closed and if this failed, would the machine fail to power up?

[SMDFlea]

Re: HP Envy 17-j053ea dead. What to look at next?

Test and post the voltages on all large square grey coils

Beginner's guidelines https://www.badcaps.net/forum/showthread.php?t=88758

[rich555]

Re: HP Envy 17-j053ea dead. What to look at next?

Test and post the voltages on all large square grey coils

Beginner's guidelines https://www.badcaps.net/forum/showthread.php?t=88758

OK, will do. Thanks.

[rich555]

Re: HP Envy 17-j053ea dead. What to look at next?

Had a poke around with the scope. 20v is present at the mainboard connector. 2.8v on the nearest inductor. nothing on any of the others.

There is 3.3v on 3 of the pins on the power switch connector (6 pin).

When I press the power button, pin 1 pulses once, for 1ms.

Pin 2 stays at 3.3v

Pin 3 goes to 3.3v and stays there for 6.7 seconds then drops back to zero.

Pin 4 sits at 3.3v and drops to zero for as long as the button is held down.

Pin 5 sits 3.3v

Pin 6 sits at zero.

I assume there is a signal to the PSU to start up and for some reason its not starting.

[mon2]

Re: HP Envy 17-j053ea dead. What to look at next?

Post any pics with silk screen markings on the logic board with hopes we can locate a schematic. Not impossible to repair without one but saves time if possible.

The 20V is likely from the DCin connector and then there should be 2 x DCin mosfets.

These mosfets will be enabled via the gate pin # 4 of each by the ACDRV of the charger IC. We need to know which charger IC is onboard.

The 3v3 you are measuring could be the always on rail (or not).

[rich555]

Re: HP Envy 17-j053ea dead. What to look at next?

Post any pics with silk screen markings on the logic board with hopes we can locate a schematic. Not impossible to repair without one but saves time if possible.

The 20V is likely from the DCin connector and then there should be 2 x DCin mosfets.

These mosfets will be enabled via the gate pin # 4 of each by the ACDRV of the charger IC. We need to know which charger IC is onboard.

The 3v3 you are measuring could be the always on rail (or not).

The battery charger is a BQ738.

I assume there is a chip than manages the power button and fires up the main psu? I have found plenty of Ti voltage regulators scattered around.

The mainboard has This on the silkscreen: Dynamic KM-VO E25540094V 1346K if that helps.

[rich555]

Re: HP Envy 17-j053ea dead. What to look at next?

on the underside, the mainboard has: 17SBGV2D-6050A2549801-MB-A02

[rich555]

Re: HP Envy 17-j053ea dead. What to look at next?

Found schematics for HP Envy 15SBGV2D-6050A2548101 and it looks to have a lot of the same parts.

There's a nice power up sequence chart and a block diagram of the power supply.

Got something to go on now!