HP Envy 17-ce009nf laptop that won't start

[Christian0734]

Re: HP Envy 17-ce009nf laptop that won't start

What are the top side markings of PU4401 ic in this last picture? This is the square ic with pins on each side and close to the memory socket.

It's an 'Intersil 9538BH' battery management chip. The first thing I need to do is to fix my big mistake before addressing the initial problem! I've ordered the 3.2v/5v chip that is overheating, but it's not guaranteed that something else isn't causing the fault.

[Christian0734]

Re: HP Envy 17-ce009nf laptop that won't start

I believe it is essential to find the schematic or the boardview of this motherboard. I can't even locate the main power lines. I observe that after removing the 3.2v/5v chip, which was heating up a lot, now there are two mosfets that heat alternately. That is, when I send current to the power connector, it's the one on the right that heats up first, and then possibly the one on the left. I'm a bit lost...

[SMDFlea]

Re: HP Envy 17-ce009nf laptop that won't start

I believe it is essential to find the schematic or the boardview of this motherboard. I can't even locate the main power lines. I observe that after removing the 3.2v/5v chip, which was heating up a lot, now there are two mosfets that heat alternately. That is, when I send current to the power connector, it's the one on the right that heats up first, and then possibly the one on the left. I'm a bit lost...

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

2. What not to do
2.7. Don't apply power to the board with missing components
As a general rule, if a component is on the board, it's because it's useful for something. Engineers don't like adding a bunch of useless components on the board, it's harder to draw the schematics and route on the PCB.
Some of them can be removed without creating problem if power is applied, but others can kill the board with no possibility of repair.
For example, if you remove a buck controller or a MOSFET driver, the MOSFET gates will be floating. They'll charge up enough so that the MOSFET turns on. Of course, you don't want the 19V from the main power rail to go straight through the CPU VCore MOSFET to the CPU.

[Christian0734]

Re: HP Envy 17-ce009nf laptop that won't start

I understand your message well. I still wanted to know if it was the 3.2v/5v chip that was short-circuited, but thank you for your warning.

[Sephir0th]

Re: HP Envy 17-ce009nf laptop that won't start

No, you have not understood. "First do, then think" is the opposite of systematic troubleshooting.

Meanwhile you made the issue worse two times in a row. The first time by injecting 13Volts into what I assume is a 5Volts rail and the seconds time you powered the device with High-Side Gates of 3Volts and 5Volts left floating. The Mosfets are heating up because you probably send 13(?)Volts through the High-Sides into the 3.3V and 5V rail (again) which most likely leave this board as no-fix from here.

Curiously enough you did not took even one single resistance measurement so far.

This all is no problem. That the first three or four boards you're trying to fix end up as no-fix is simply normal. However, i don't know who taught you to do how you do, but if you proceed like that with future repairs, you'll kill many boards without realising.

[Christian0734]

Re: HP Envy 17-ce009nf laptop that won't start

That's not exactly the sequence of events. Originally, I had a problem with the main power supply, all my voltages were there, I had no short circuit and the computer was running only on battery.

Without the battery and with the main power supply, it would try to start and stop after 2 seconds, looping 2 or 3 times then nothing. Then inadvertently, I took the probe that I used to power the computer through the battery connector (13v) to measure the 3.2v tension on a fuse. This was a big mistake, I admit, usually I don't connect my multimeter probes to the stabilized power supply, I have other probes for that! I don't know why I made this mistake, but it's too late. I'm not used to injecting current at random, I already knew that the computer was working on the battery, this was demonstrated by a partially charged new battery. Then yes, I briefly powered on with a 3.2v/5v chip desoldered from the board to check with the thermal camera which other component could be heating up, second mistake...

Currently I'm waiting for your ideas before replacing the 3.2v/5v 1285B chip that was heating up after my unfortunate short circuit. Thank you for your attention and your time.

Here are the measurements on the inductors.

[Sephir0th]

Re: HP Envy 17-ce009nf laptop that won't start

One coil with 0.2 Ohms to GND which I assume is the +3.3VALW and another dead short to the left of the CPU which I assume is the +1.05VALW.

If this is true, and unfortunately this outcome fits pretty good to the history, then there is nothing to do for this poor board anymore.

[Christian0734]

Re: HP Envy 17-ce009nf laptop that won't start

What does 'VALW' mean? The measurements were taken with one less 1285B chip, I don't know if that changes anything.

[mon2]

Re: HP Envy 17-ce009nf laptop that won't start

VALW = always on voltage

[mcplslg123]

Re: HP Envy 17-ce009nf laptop that won't start

Dont waste your time and money on this board and go by @Sephir0th's suggestion. He'is pretty experienced man and you should take his criticism in good spirit to upgrade your understanding of laptop motherboard repair.

[Christian0734]

Re: HP Envy 17-ce009nf laptop that won't start

Dont waste your time and money on this board and go by @Sephir0th's suggestion. He'is pretty experienced man and you should take his criticism in good spirit to upgrade your understanding of laptop motherboard repair.

yes of course, thank you.