820-3332-A Macbook Pro Retina 15" Shorted on PPBUS_G3H

patrickribbsaeter

New member
Hi, have a customers Macbook pro retina 15" 820-3332-A
  1. I have pp3v42(green and yellow light) on the charger.
  2. No water damage, computer just shut off for customer
  3. L7030 > Pin 2 outputs 1.5v.
  4. R7020 pin2 only 16.5v.
  5. U7000 pin3(AC IN 3.8v)
update: it seems u7000 is shorted. The IC its burning hot. So it must be a short on the IC, or could it be something else shorting it to ground?

Any suggestions pls? thanks
 

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2informaticos

Administrator
Staff member
"R7020 pin2 only 16.5v."
No voltage on pin2???
That means burnt resistor; never saw this...
Check for short C7021/22 and pin 28/ISL6259.
Also one of C7030-36 can be shorted...
 

patrickribbsaeter

New member
1. I changed the U7000 and I got the green/orange light back. Might have been a bad u7000. Because it was working when i started troubleshoot.
2. Still NO fan spin though.

Ok, i will check what 2informaticos said above. and give you update on that
 
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patrickribbsaeter

New member
"R7020 pin2 only 16.5v."
Pin2 now suddenly 194.6 millivolt. this happened now after i changed the u7000. before it was 16.5v. (I like to point out i took the U7000 from a donor board) Im waiting for new IC's & parts to come in. Could that be the problem.

No voltage on pin2???
only 194.6 millivolt.

That means burnt resistor; never saw this...
There are more places now on PPBUS_G3H line which is not showing correct reading. Its like te voltage is confused and cant zone in on a reading. I continue the trouleshoot the parts not showing correct voltage and post them here.

Check for short C7021/22 and pin 28/ISL6259.
pin 28/ISL6259 Showing 228 millivolt. same thign there, DMM cant read properly. and C7021/22 same thing.

Also one of C7030-36 can be shorted...
Same thing, the volt fluctuates same as i stated above. Strange! I will try to reflow the u7000 and see if that improves the Voltage ralls.

Will do some more troubleshooting and give u update asap.
 
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2informaticos

Administrator
Staff member
"No voltage on pin2???"
Mea culpa, read it as "No voltage on pin1???"

I asked to check for short on several points.
That means diode mode (red probe to ground), NOT voltage...
 

patrickribbsaeter

New member
C7021 = 0.520 (Diode mode)
C7022 = 0.525 (diode mode)
ISL6259 pin28 = 0.525 (diode mode)
C7030 = 0.513 (diode mode)
C7036 = 0.516 (diode mode)
R7020 (pin 2, im ttaking diode mode from testpoint which is connected to R702 pin2) I get 0.518 (diodemode)

I still have green/orange light, but no fan spin..

What should I check next?
 
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patrickribbsaeter

New member
Q7030 (pin 5) = 16,1v
L7030 = 290.4mv on both pins
resistance to ground on L7030(pin1) = 50 ohm

The transistor Q7030 is super hot, burning hot so 100% its shorted. Im going to change it and let u know..
 
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2informaticos

Administrator
Staff member
Q7030 is not shorted; you get different input/output voltages!!!

Remove F7040/41 and check which side remains the low value (50 ohms) to ground.
 

patrickribbsaeter

New member
I was a bit to quick. I removed the Q7030, added another Q7030 from another board. but not I put back the first Q7030.. and suddenly the L7770 is getting super hot.. I might have screwed it up more by removing and putting back the Q7030.. problem now is the COIL (L7770)
 

patrickribbsaeter

New member
fi i keep DC supply on for a while, now something else shorts.. The crystal shorts now... But not the coil anymore.. Why's that?

Q7080 is getting hot now. only this one.
 
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2informaticos

Administrator
Staff member
Seems that you don't want to follow our advices :(
We cannot help in this way!

"Remove F7040/41 and check which side remains the low value (50 ohms) to ground."
Be sure to solder Q7030 properly...
 

patrickribbsaeter

New member
Sorry, I was just going a little bit to fast ahead. Wont do that again.. Just want to get this board fix.. guess my teqhnique will improve. So lets do this step by step!

Which is the correct way to measure Resistance to ground on the coil L7030?
Because i get two different readings when connecting the Black probe to ground compare to Red probe on ground.

thanks
 

2informaticos

Administrator
Staff member
Is OK, post both values.
But I asked you to check that on both side of F7040/41 fuses; after removed them.
If problem remains on U7000 side, is not complicate.
If the low value is on system side, then you can expect troubles...
 

patrickribbsaeter

New member
I removed the both fuses

Resistance mode.

F7040 pin 2 = 35 k ohm

F7041 pin2 = 35k ohm


Diode mode:
F7040 pin 1 = 0.472
F7040 pin 2 = 0.035

F7041 pin1 = 0.472
F7041 pin2 = 0-035

When trying to measure resistance. The DMM, sometimes has hardtime to make a reading. Sometimes showing K ohms.
 
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patrickribbsaeter

New member
Maybe i screwed something up when removing the Mosfet earlier. When using wick, (following Louis examples) the solder only get smeared out all over the joints. So the 3 Source pins are connected now with solder. But they shoudl be according to schematic(So thats not an issue I suppose?) Not the best practice, dont understand how Louis manage to do it. Need to find a better solution to wick pads. I checked the pins on mosfet with continuity mode and they are not connected /shorted together so thats good i guess?
 

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patrickribbsaeter

New member
1. When putting back the two F7040/41 suddenly when applying voltage the Q7080 gets super hot, I burned myself just now.

2. When removing the F4040/41 its suddenly showing 17.6v on F7040(Pin1).
 
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