Hp pavilion 14 - No display

[Nagyesz]

So this is why the computer won't turn on? Are you sure this is the source of the problem? Can I measure it somehow?

[mon2]

Certainly do wait for feedback from other techs but to me, this IC is defective. It is deformity that is not present on a normal IC and often indicates that a transient went through this device -> caused internal damage to the semiconductor die and the same pressure caused the packaging to bubble up. Also, moisture combined with rapid heat can also cause such micro cracks / bubbles which in the PCB production world is named as 'popcorning'. This is a key reason that parts are gently baked before mounting through SMD ovens and that is to draw out or bake out the moisture.

Can also be caused by reflowing with a hot air tool with too high of a temp and heating of the component at a too high rate. The moisture expands on the inside and as no escape.

What is Popcorn Effect in PCBA Process (pcbonline.com)

[Davi.p]

Hi..
That can't be a popcorn effect as there is no BGA die on a substrate, the popcorn name refers i guess to the tin balls that pops out the side glue between substrate and bga die..

to the O.P., scratch it away and see if a hole remains or is only a rosin drop.. bye

[Nagyesz]

Thank you for the responses so far. I scraped it, and I don't see a hole anywhere.

[mcplslg123]

Post#17 indicates ,you've missing enables(PM_SLP_S3/PM_SLP_S5). These enables will come from PCH. Check the SIO for short as mon2 has suggested(both these enables will go to SIO also).

[Nagyesz]

Thank you for the response. Unfortunately, I am not very skilled, especially when it comes to SIO chips. Where should I look for the short circuit? On which components or which pins on SIO?

[Nagyesz]

Edit: I injected 1.2V into the PL8300 inductor, and nothing really heated up.

[Davi.p]

Has it got a double chip cpu with integrated graphics? I suspect bad bga, try hard freezing it,.maybe in the freezer in a bag and then test it when frozen..

[Nagyesz]

Thank you for the idea, to be honest, I'm not sure how well this might work, I will wait for someone response because the 1.2V RAM line is still missing, and I have no idea what to do next. ( It has integrated graphics, yea )

[Nagyesz]

Here's a little status update: I got a 135W charger, but unfortunately, the 1.2V for the RAM is still missing.
What else should I try experimenting with? Where should I inject the voltage? The 1.2V is missing at RAM IC controller.
Would replacing the SIO chip solve the problem?

[Sephir0th]

Check PL8400 voltage and resistance to GND please

[Nagyesz]

PL8400
2.8 ohm to gnd
1.8V power on state

[Sephir0th]

You realized that 2.8 Ohms is a partial short-circuit on the 1.8V rail?

[Nagyesz]

I thought that low resistance was acceptable on low voltage lines.
What does it mean if the 1.8V line is shorted? What should be done?"

[Sephir0th]

The Classic 1.8VALW is supposed to read in KiloOhms.

Voltage injection is the next logical step.

[Nagyesz]

Will injecting 1V and say 2-5A into the 1.8V line be sufficient?

Thanks for the tip, by the way.

[Sephir0th]

1 Volt is a good starting voltage. The taken current will tell us whether we have to raise the voltage or not.

Good luck

[Nagyesz]

PL8400
On 1V taking 0.4A

Should I raise the voltage?

[Sephir0th]

If you have a thermal camera there might already something to spot.

And don't forget to remove the heatsink and to clean the CPU/PCH BGA package, since the PCH is a suspect too.

If you can't feel anything you're allowed to raise the voltage to 1.8 Volts max(!).

[Nagyesz]

I checked at 1V and nothing was heating up at all, not even at 1.8V. However, after a few minutes, there was a slight warmth coming from the processor, but nothing serious. What should I do now?

On 1.8V taking 0.69-0.73A