Dell E7470 - Do I need a programmer?

[Fr4gz0n3]

Hi everybody. I'm working on a Dell E7470 that does not power up.

I've found:

• A destroyed P mosfet (PQ804) connected to the docking station port power line

• A shorted IC that if I'm right it should be the super IO (UE1)

I want to ask you if it's the super IO indeed and if, as I suspect, a new IC has to be programmed.

As always thanks.

Note: At first I thought that maybe a shorted capacitor caused the IC to heat up but it's not the case and after the removal of the IC all the shorts around the board disappeared.

[khaahk]

Re: Dell E7470 - Do I need a programmer?

ECE5048 does not need reprogramming, only MEC5085.

[Fr4gz0n3]

Re: Dell E7470 - Do I need a programmer?

Good news! Thank you very much

I ordered the new IC, let's hope the board is salvageable. The old one fused with the board because of the heat caused by the short, so had to push the hot air temperature quite a bit and for long time to be able to remove the IC.

The p mosfet is not replaceable as is because the pads burned and lifted. I'm thinking of removing both PQ804 and PQ805. I'm not interested in the docking station so it shouldn't be a problem. I'm just worried this action can cause problem on the board. What do you think?

Thanks

[Fr4gz0n3]

Re: Dell E7470 - Do I need a programmer?

Today I received and soldered the IC (ECE5048).

I also remove the 2 mosfets connected to the docking station power lines (PQ804 and PQ805). PQ804 was the one burned and pads at its location are missing due to the original short.

The good news is that now the laptop boots up and passes all the diagnostics, the bad one is that the AC adapter tests failed.

Now the machine goes in energy saving mode and show me the "infamous" warning: "Alert! The AC power adapter wattage and type cannot be determinated...".
I know that usually this is caused by a compatible AC adapter, but this is not the case, because I have a genuine Dell 65W AC adapter.

My first thought is the removal of the 2 mosfets caused something, but I'm not superconfident in the circuit schematics analysis. I uploded the an extract of the documentation where I marked the 2 mosfets removed.

Does someone have any idea?

EDIT: In windows the battery reports 0% charge. Don't know if there is a "physical" missing connection or is just some kind of software lock.

[Stevedb]

Re: Dell E7470 - Do I need a programmer?

What abouth pin bat pres and acdet how much voltage do you have. Did also check pq802 not shorted.

Regards

[Fr4gz0n3]

Re: Dell E7470 - Do I need a programmer?

Thank you for the reply.

• PQ802 seems fine. No shorts between source, drain or gate.

• The battery is dead: 0v reading. On the 3 control pins I have:
  PBAT_SMBCLK_C -> 3.3v
  PBAT_SMBDAT_C -> 3.3v
  PBAT_PRES#C -> 0v with battery | 3.3v without battery

I think the battery is detected correctly because if I remove it the system correctly reports that there is no battery. Do you think it can be simply a dead battery problem?

Can the dead battery problem be the reason behind the AC charger identification problem?

EDIT: I checked also the charger connector and at the center pin I have 3.3v

[Stevedb]

Re: Dell E7470 - Do I need a programmer?

Did you already checked double diode pd6 ? For short. Psid line check that line if everything is good there.

[Fr4gz0n3]

Re: Dell E7470 - Do I need a programmer?

I've made few tests with the AC adapter connected and without battery.

PD6 seems ok. I also tried to swap it with PD7 but nothing changed.

PQ3 and PQ4 also seem to be ok:

PQ3:
S -> 3.2v
D -> 3.2v
G -> 5v

PQ4:
E -> 0v (GND)
C -> 5v
B -> 0.4v <-- not sure about this

Readings of the resistors are correct. I cannot find one PR9 (or PR11) and PR10. It can be easier if I have the boardview file.
If it's not a problem with this part of the board my guesses are:
- A faulty AC adapter
- A Problem with UE1 which I replaced because the ID lines go to this IC.

What do you think?

[khaahk]

Re: Dell E7470 - Do I need a programmer?

PQ3 seems ok, so should PQ4 because it is giving 5V to PQ3 gate. Check PR7 for 33 ohms and if it is ok then next is PU1. I have seen both of them fail. Of course it is possible that the UE1 did not seat correctly (they are tricky to solder). You can check connection between UE1 B24 and PU1 pin 4. (the B contacts are the ones without external solder leads to the edge but they are visible between the A contacts.)

[Fr4gz0n3]

Re: Dell E7470 - Do I need a programmer?

Thanks for the reply. I'll check them ASAP.

Unfortunately the original PU1 melted into the first board layer, so the heatsink central pad surface is everything but even. After the soldering I also performed a reflow to have more chances of success.

Another problem I noticed is the M2 wifi board not detected by the bios. But I don't think the issues have something in common.

[khaahk]

Re: Dell E7470 - Do I need a programmer?

You mean UE1 not PU1 i presume.

The way i solder them is that i tin the contacts on the mainboard and on the chip and then reflow. Pressing down while doing reflow is not recommended because then there might be short circuit between the B contacts and you can't see it. If the surface is not even then the task is much more difficult.

Thanks for the reply. I'll check them ASAP.

Unfortunately the original PU1 melted into the first board layer, so the heatsink central pad surface is everything but even. After the soldering I also performed a reflow to have more chances of success.

Another problem I noticed is the M2 wifi board not detected by the bios. But I don't think the issues have something in common.

[Fr4gz0n3]

Re: Dell E7470 - Do I need a programmer?

You mean UE1 not PU1 i presume.

Yes I meant UE1.

The way i solder them is that i tin the contacts on the mainboard and on the chip and then reflow. Pressing down while doing reflow is not recommended because then there might be short circuit between the B contacts and you can't see it. If the surface is not even then the task is much more difficult.

Same procedure. The first time i used chipquik flux, the second time I used rosin+IPA because is tinner and flow better under the chip.

I confirm PR7 is ok: exactly 33 ohm

About PU1:
1 -> 3v
2 -> 0v (GND)
3 -> 3.3v
4 -> 3.3v
5 -> 5v
6 -> 1.7v (average)

Tomorrow I'm gomma test another AC adapter in case the one I have is faulty.

[Fr4gz0n3]

Re: Dell E7470 - Do I need a programmer?

Shame on me

I guess I found the problem


It took me a bit to capture this picture. Obviously I was on the opposite while I was soldering and probably I need a microscope. I wonder how it even boot up.

Tomorrow I'll remove the IC and try to find a way to flatten the surface. Any tips?

[mon2]

Re: Dell E7470 - Do I need a programmer?

Apply lots of flux -> high heat -> enough air pressure to apply onto the top surface only. The surrounding parts will fly around if you do not.

Flow the air in circles but cover the entire IC as this part likely has a metal belly.

When done right, the part should sink onto the PCB, naturally. It will help to have an underside pre-heater / table.

With enough heat and flux, the IC will align itself like a soldier.

[Fr4gz0n3]

Re: Dell E7470 - Do I need a programmer?

It's a good tip, but I'm worried the problem is the central ground pad to be not flat due to the original IC fused with the board. The area propably it's not clean and flat enough.

[Fr4gz0n3]

Re: Dell E7470 - Do I need a programmer?

I can confirm the central pad is bumpy. I removed as much solder as I can and now I don't know what to do to flatten the surface. Maybe I can try with a fiberglass pen or a micro grinder as a last chance. Any idea?

[Fr4gz0n3]

I give up

I spent to much time trying to flatten out the ground pad using a micro grinder.



For as hard as I tryed I can solder correctly only two sides at time, no more. To solve this issue I was thinking of some kind of riser for the contacts, but honestly it's too much effort for this laptop.

FYI removing the UE1 IC the laptop works as mentioned before. The wifi M2 slot does not work and, most important, the AC adapters are not recognized even if DELL original, so the battery cannot be charged.

Thanks everybody for the support.