No signs of life OLED

Recently bought an OLED that died after being dropped. Because of this I can´t be sure the APU’s solder balls are all ok, so take this in mind.

As for now symptoms are:

  • Console charges fine and VBat is present. So I assume good BQ and M92.
  • When plugged to a charger with no battery, current draw is 0.
  • When Injecting Vbat, current draw is also 0.
  • MAX77620 doesn´t create any Voltage rail when shorting EN0
  • I’m uncertain of the correct value but I’m measuring 2.2k on EN0 resistor. I know on regular Switches this resistor is a 150R one.

I assume MAX IC is faulty but how can I be certain the EN0 is being pulled low correctly before changing anything?

I would check if the fuse is fine. 0 amps draw is very unlikely if the power reaches the m92t36.

You’re right. Fuse is good, with no battery it takes between .02 and .04A.

Still 0A when injecting Vbat.

Maybe I missed something. What is the point for injecting voltage at the Vbat line?

The line is powered by the battery (2.7V - 4.2V) or by the bq (4.2V) while charging. If the power/start button isn’t pressed, there shouldn’t be any current draw.

To see quickly if there is a short on any of the VBat line ICs. Got a thermal cam, found this is easier than just probe the whole board for shorts lol.

Was expecting to see some small idle power draw from the MAX and obviously to draw power when turned on. But it draws nothing on both cases

If the battery is plugged in and you can read its voltage at the VBat, there should be any shorts on this line.

What is about Vsys? This is the main power line which is feed by bq with battery or whatever usb c power input.

I’m retarded lol. Was calling Vsys Vbat hahaha. I was injecting Vsys not Vbat, my bad.

Ok. This makes more sense. So you have a shorted Vsys?

Nay, I injected Vsys trying to turn it on with the bench PSU (at least first stage boot) but i get no draw when idle and also no draw when powering it on.

Vsys gets to the MAX and the 3.3V regulator but nothing is taking current nor creating their rails when trying to power it on.

What I suspect is bad MAX, but I want to make sure the “On” signal is actually good and reaching the IC.

For the record, I measure .5 voltage drop on EN0 pin on the FPC connector.

Well, once again and to no one surprise, I’m retarded.
Found out I was trying to turn it on shorting the fricking fan connector.
So after injecting Vsys and actually turning it on, the console was taking like .6A; got the thermal cam out and the 3.3 regulator was lighting up like hell.
Since I got no OLED donor and the normal Switch regulator can´t be used as replacement here, I’ll order some and replace it later.

You are not alone. I’m also able to fool myself. But it is all about learning. :joy:

Update on this one. New regulator came in, replaced it and found the cap next to it was shorted. Replaced that one also and the console still wont boot.

Tried a full boot from bench PSU and the console takes 100mA and it’s stuck there.

Did some small probing and the 1.3V line from the MAX is not there and the 1V it’s just .85V

Straight up change MAX?