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I replaced U7100 with minor changes.....
PPVCCSA_S0_CPU came up = 1.1V
But PPVCC_S0_CPU =0V
And now CPUVR_PGOOD = 0V
Now I get 20V / 0.36Aon the amp meter....
How I get the vcore back?
Should I expect a dead CPU?
Or should I try my luck with flashing the BIOS...
OK as I said the optical inspection of U7100 and U7210/20/70 is witout any doubts.
I checked now all the VIN-pins, VCC-pins, EN-pin and pgood-pin....
All the pins have the voltage they should have.
I would like to learn more about the U7100-ic. It seams it is responsible for the vcore-lines and...
The Logicboard have no visible corrosion or burn marks.
The whole machine is clean.... I mean CLEAN! No dust in the fins!
I'm the first opened it.
No shorts on the coils!
All the S0-lines comes up except:
PPVCC_S0_CPU =0V 4.8Ohms tg
PPVCCGT_S0_CPU =0V 2.8Ohms tg
U7000 is responsible for PPBUS_GH3 and charging.
I don't think it is faulty because you have PPBUS 8,4V
For charging it has to communicate with the SMC and the battery. If it can't communicate there is something wrong with the data lines (Page42) or current sense resistors (Pins 17,18,27,28)...
You can say there is no short to ground on the Rail.
I missed to say EN PIN12 has to be high to make the whole chip to work.
PIN12: P5V3V3_REG_EN comes from SMC_PM_G2_EN!
Is this signal present?
Can you list up all EN pins? Voltages?
Well this is a good good question. Actually a was lucky since I had no idea which one was bad.
I was looking in the web how to identify which chip is bad depending on the address in the log:
FAILURE! Data mismatch at local BUFA address 0x00000001394fa4e0, BUFB address 0x000000017e406ce0
I have to add some information here:
I've noticed that every single machine with faulty SPI ROM that I had also had a bad RAM Bank!
When I think about it it makes sense. The faulty RAM writes back some strange bits and this fucks up the SPI ROM!
This will most likely happen if you try to update...