A2289 No PPBUS_G3H

[Stephen]

PPBUS_G3H is shorted. Injected voltage at F7000
There is a short but no short is present, so went ahead and tested restistors on ISL9240 area All resistors are in 5% range of 1OHM. Replaced the ISL9240 and still no power.

5Volts .03Amps

Went ahead and replaced both CD3217 chips, still same issue. tried injecting voltage again but nothing is happening. Would like a little direction.

Checked CHGR_MVR_EN and it is not present, but what is odd is I just replaced the ISL9240 and that still didn't bring it back. Replaced it again with another we had in stock assumed it was bad, still no CHGR_MVR_EN

This one is kind of making me feel MEH. I fixed one exactly like this today and now this new one is breaking my balls lol. Same issue it seems but seems to not want to turn on and get pass 5v .03Amps.

just want to add.
I'm seeing 5v .03 amps then the amps drop to 0.00 then jump back to .03amps every second

[mon2]

Re: A2289 No PPBUS_G3H

Remove F7000 and power up again to test PPBUS_G3H.

[Stephen]

Re: A2289 No PPBUS_G3H

Removed F7000

0Volts on PPBUS_G3H

[mon2]

Re: A2289 No PPBUS_G3H

0 volts on both sides of the removed fuse?

[Stephen]

Re: A2289 No PPBUS_G3H

0Volts on PPBUS_G3H
12Volts ons PPVBAT_G3H_CHGR_REG

I also did check the fuse and it is not blown

[Stephen]

Re: A2289 No PPBUS_G3H

bump

[mon2]

Re: A2289 No PPBUS_G3H

What is the resistance to ground of PPBUS_G3H (without F7000)?

[Stephen]

Re: A2289 No PPBUS_G3H

3 to 3.5 ohms without F7000 on PPBUS_G3H

[mon2]

Re: A2289 No PPBUS_G3H

Inject 1 volt onto this downstream rail and check who heats up. Likely a cap and hope not the CPU. Do not increase the voltage

[Stephen]

Re: A2289 No PPBUS_G3H

you want me to inject 1volt 5 amps into PPBUS_G3H?

Because if so I did that with the F7000 fuse removed, shows signs of short still, nothing on the thermal gun or ouchy test. Sprayed isopropyl all over nothing shows short on the board. I keep leaning towards the ISL9240 but I just replaced it three times. There is no way 2 new ISL were bad out the box.

[mon2]

Re: A2289 No PPBUS_G3H

Yes. This is the downstream (consumer) side of the removed fuse. This is the side showing a partial short of a component. As you do this injection, the shorted part will heat up. Often a tantalum capacitor that will crack open under the pressure.

If the high side mosfet of the CPU rail is shorted, then the CPU will heat up and it is game over since the CPU replacement requires proper bga rework tools.

[Stephen]

Re: A2289 No PPBUS_G3H

Yeah injected voltage 1 volt into PPBUS_G3H with fuse removed. CPU does not heat up. Nothing is heating up. I am assuming ISL9240 is still bad?

[mon2]

Re: A2289 No PPBUS_G3H

Is the CPU with a heatsink? If yes, it may be dissipating the heat.

Q: while injecting, what is the current consumption of your power supply?

[Stephen]

Re: A2289 No PPBUS_G3H

Removed Heatsink, no increase in heat.
When voltage is injected consumption is .239 Amps at 1Volt. Shows a short basically.

[mon2]

Re: A2289 No PPBUS_G3H

Remove all power. Measure the resistance from the same PPBUS_G3H to PPVCC_S0_CPU = Vcore for the CPU. Checking to see if the high side mosfet is shorted. Does not appear to be the case.

If clear, then we can consider to increase the voltage.

[Stephen]

Re: A2289 No PPBUS_G3H

I am getting 1 ohm and dropping a little around .5 ohms to 1.0 ohms at PPVCC

[mon2]

Re: A2289 No PPBUS_G3H

To be clear, you are measuring the resistance between the PPBUS_G3H pad and the other meter probe is @ PPVCC_S0_CPU ?

[Stephen]

Re: A2289 No PPBUS_G3H

Yes

PPBUS_G3H (F700) to PPVCC_S0_CPU (C1027)

Correction.

4OHMS at C1027

[Stephen]

Re: A2289 No PPBUS_G3H

Unless I was checking wrong should I be checking a specific cap for this area? Kind of lost me there apologies

[mon2]

Re: A2289 No PPBUS_G3H

Inject the 1 volt again @ F7000. Measure with care the voltage to ground @ C1027. Do you see a voltage @ C1027 ?

Concern here is that the high side mosfet may be defective and respectively, the high voltage of PPBUS_G3H has killed the CPU.

PS: You will need to grow a few extra arms.