820-00923 not turning on

arnonabuurs

New member
Hello, this board did not turn on. I got 19v and 0 amp. FOund a short in PPBUS, smoke out of U7960 when put power in it. I replaced U7960, short is gone. Now when I connect power I dont get 19v anymore only 5v, I do have 13v on PPBUS now..... :rolleyes:. Since 19v showed up before I assumed nothing is wrong with the USB control chips, but now it changed to 5V should i be looking at those? Or if U7960 is shorted the CPU is fried? PP3V3_G3H = 3.4v
 
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arnonabuurs

New member
Attached image from D3302 some solder:eek:balls popping out might be a clue, but no short on PP20V. I have 3.3v and 4.7-4.8 on 5v.
 

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2informaticos

Administrator
Staff member
Do you mean 4.8V at C7607?
Which other coils get voltage.
All USB ports stay at 5V now?
However, if SMC allows 13V on PPBUS_G3H, you should get more voltages on the board.

Be aware, burnt U7960 could already killed CPU.
U7800 can be also affected.
 

arnonabuurs

New member
OK some update, I think it was not completely dry yet after ultrasonic as I left it overnight and now I get 20v, but only 0.52amps. Will check more voltages and report back later.
 

arnonabuurs

New member
So i got all accept CPU Vcore and CPU gets warm = RIP?

PPBUS_G3H = 13.04v

PPBUS_HS_CPU = 13.04
PP3V3_G3H = 3.4v
PP3V0_G3H = 2.99v
PP5V_S5 = 5.1v
PP5V_S4 = 5.1v
PP5V_S0 = 5.1

PP3V3_S5 = 3.3v
PP3V3_SUS = 3.3v
PP3V3_S4 = 3.3v
PP3V3_S0 = 3.3v

PPVCC_S0_CPU = 0v

PPVCCIO_S0_CPU = 0.98v

PPVCCEDRAM_S0_CPU = 0v

PP1V2_S3 = 1.2v

PP1V8_S0 = 1.8v

PP0V6_S0_DDRVTT = 0.6v
 

2informaticos

Administrator
Staff member
"FOund a short in PPBUS, smoke out of U7960 when put power in it"
Did you inject voltage on PPBUS_G3H to heat U7960???
That could killed the CPU; if it wasn't fried already.
 

arnonabuurs

New member
How do you find a short in PPBUS if the board is clean without putting power in it? I put 3v in a 13v line.
 
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2informaticos

Administrator
Staff member
3V there fried CPU...

"without putting power in it?"
So many times explained on the forum.
ALWAYS REMOVE SHORTED high-side MOSFET, if is the case.
You don't need power to find it.

After removing U7960 you've could see no short anymore, adn NO REASON to inject volatge, on PPBUS.

Use search function on the forum, if you need more details.
 

arnonabuurs

New member
dude i know how to use the search function but i dont pay 29 USD for the 3 question i ask per month to spend my time searching..... I assume you get paid to answer questions? If i search i dont need a paid forum.
 

2informaticos

Administrator
Staff member
You are free to wait, or use search button...

"Use search function on the forum, if you need more details."
I was talking about how to find such kind of shorted high-side MOSFET.
Too late now, probably CPU is dead.
 
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