Lenovo V14 G2 heating component

[Nagyesz]

I haven't downloaded the schematic yet, as I still want to master the bv for now, but I'm increasingly seeing that knowledge of both will unfortunately be necessary very soon

So, should I start by injecting 1V into PJ6003 first, regardless of which rail? (+3VLP, +3VL)

To be honest, I've looked at the schematic, but my eyes aren't quite adjusted to it yet. What will my next will be?

[mon2]

Boardview for the NM-D521 appears to be a match to your board. Therefore we have access to the schematics as well.

[mon2]

Yes, if you have a variable power supply, inject 1 volt onto this rail and whomever is shorted will heat up. You can use the thermal camera or IPA to hunt down the part.

[Nagyesz]

I had to take a closer look a few times.
Unfortunately, I don't have a thermal camera yet, so I used basic methods,
I did find something that was heating up, but it was far from hot. It was drawing 0.2A at 1V, and it was UE1 that I felt was getting warm. Is there a way to be sure that this is where the problem?

[mon2]

Hunt for RE5. This should be a solder blob or a 0 ohm resistor. If you remove this 'short' then you will be removing UE1 from this common power supply as a load. Afterwards, test the resistance again to see if it is higher or not.

Recommend to source IPA (pharmacy grade is recommended) alcohol as it is more pure. Then pour over the parts you suspect. The heat will make the IPA evaporate faster than the cooler parts.

[Nagyesz]

I'm sorry for asking again, I found the RE5 +3VL_EC is OL, while the +3VL is 4.6 ohms. These two are blob, how can I 'remove short', or what to do with the blob?

[mon2]

Post a clear picture of RE5. From the schematic, this should be a short on the trace or a 0 ohm resistor. Either way, if this part is present, you should have 4R6 ohms on each test point.

With no power to the board, meter in resistance mode. Place one meter probe on +3VL and other meter probe @ +3VL_EC. What is the resistance? It should be ~0 ohms (Not OL = over limit).

[Nagyesz]

Not entirely, if is it RE5 (pic) is likely the pin 1 with 0.05 ohms to the PJ6003. However, pin 1 and pin 2 show OL to eachother when measured in 20k ohms.

[mon2]

My bad. RE5 has '@' symbol = 'do not stuff' on these schematics so this part will not be populated.

Can you confirm that the WLAN card is removed from the long black socket in the above pic? If not, remove it and check if the short remains. The WLAN card is one of the loads on this same power rail.

[Nagyesz]

I'm sure there is no wlan card.

4.6 ohms is still on the line.

So what we know for sure is that something on this line is shorted, and when 1V was injected, only the UA1 heated up.

What should be done now?

[mon2]

What are the topside markings on UA1? Share a pic. Is it the sound card IC = ALC3287?

[mcplslg123]

PJ6003 solder blob must be removed to proceed further. You need a soldering iron,de soldering wick,good quality flux to remove the excess solder to separate the jumper and then inject 1V to the shorted side. If nothing significantly heats up increase the voltage to max 1.2V/5A. Most likely its SIO which will heat up a bit.

[Nagyesz]

Pic about the ic which was warming: (IT8227VG-128)
Also a pic about PJ6003, do I need to further remove everything?

[mcplslg123]

To me,it seems like the jumper is not separated.A beeter quality picture of the jumper area will clarify.

[Nagyesz]

I did it. PU6001 13 pin OL, but the other line still shows 4.6 Ohms, so I'll start experimenting with the PSU on 1-1,2V

[mon2]

PJ6003 looks to be still shorted. Can you confirm?

[Nagyesz]

Yes, that is, the +3VL line remained at 4.7-4.6 ohms, and with the PSU at 1.2V, the line drew 0.25A. Nothing really heated up again, maybe the UE1 where a temperature change could be felt.

I believe it can now be the +3VL line is the main suspect. However, there was only very slight heating at UE1.

[Nagyesz]

So, is the motherboard faulty because of the SIO? Is there anything else I could check on the motherboard?

[tandoori]

So, is the motherboard faulty because of the SIO? Is there anything else I could check on the motherboard?

Did you find out something new? I got a V15 G2-ALC and the same problem.

Cheers, tandoori

[Nagyesz]

Bad SIO

I'm almost certain about this, but what's even worse is that there's no pre-programmed SIO available for sale anywhere, and I'd also need a bga machine...