MacBook Pro 2010 15in 820-2850 A Unresponsive

[piernov]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

Then measure all the power rails listed on page 7 "Power Aliases", in order G3H→S5→S3→S0.

[poisonite]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

Then measure all the power rails listed on page 7 "Power Aliases", in order G3H→S5→S3→S0.

All measured using V DC multimeter mode
G3H:
PPBUS_G3H = 12.78v
PPBUS_CPU_IMVP_ISNS = 12.78v
PPDCIN_G3H = 16.90v
PP3V42_G3H = 3.47v
S5:
PP5V_S5 = 5.13v
PP3V3_S5 = 3.39v
S3:
PP5V_S3 = 5.13v
PP3V3_S3 = 3.38v
PP1V5_S3 = 0.00v ( Mesured at c2900)
S0:
PP5V_S0 = 5.13v
PP3V3_S0 = 3.38v
PP1V8_S0 = 1.84v

Sorry for the wait, holidays got crazy lol. These are all the power rails I measured. The only major discrepency i found was on PP1V5_S3 which reads 0v instead of the expected 5 volts.
I've been measuring everything with my multimeter in V DC, is there a different setting i should be using.

Sorry, I'm a bit new to this sort of thing and I truly appreciate your help.

[dellxps15]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

PP1V5_S3 is 1,5 volt .... probably for ddr3 ram. check that circuit why not output voltage...... short, no vin no enable and so on.

[piernov]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

Yes indeed it seems like the problem is missing PP1V5_S3 which should be 1.5V.
Check for a short to ground on this rail (measure resistance to ground on L7330 for example) and look around U7300 (liquid damage, knocked off component), and make sure you get 5V on both sides of R7305.

[poisonite]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

Yes indeed it seems like the problem is missing PP1V5_S3 which should be 1.5V.
Check for a short to ground on this rail (measure resistance to ground on L7330 for example) and look around U7300 (liquid damage, knocked off component), and make sure you get 5V on both sides of R7305.

Hey, great news (i think). R7911 looks like it was ripped off the board (it's the red one in the included pictures) R3314 is also missing but it looks more like it was intentionally left off even though the schematic doesn't specify it as a "NOSTUFF" part. Also, when i measure L7330 in diode mode it comes back 0.000 (one probe on each contact point). does that mean there's a short or did I measure wrong?

Finally, when i found that r7911 was missing i touched a multimeter probe to each contact point in diode mode and the fans started to spin at full speed. then when i unplugged the charger and plugged it back in after a few seconds and the system fans started to spin slowly before ramping up to full speed again, with out any tapping.

Does this mean that by replacing r7911 the problem should be resolved or is there more to investigate?

Thanks so much for all your help so far, after over a month of working on this i'm finally making progress and it's all thanks to you for sharing your knowledge!







Note: all images have red labled for R7911 and blue for R3314

[piernov]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

R7911 is indeed required. Without it, the RAM voltage regulator will never turn on. It needs to be put back on.
R3314 is for BOM option VREFMRGN which is not populated on production boards, so it has to be left off.

For short to ground detection you have to measure in resistance mode, one probe on the line and the other on ground, Magsafe and battery disconnected.

[poisonite]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

R7911 is indeed required. Without it, the RAM voltage regulator will never turn on. It needs to be put back on.
R3314 is for BOM option VREFMRGN which is not populated on production boards, so it has to be left off.

For short to ground detection you have to measure in resistance mode, one probe on the line and the other on ground, Magsafe and battery disconnected.

Ok, i measured the actual resistance on L7330, it reads OL on both ends with the multimeter in 200Ω mode 1 probe on ground, the other on either side of the component. will replacing R7911 resolve this issue?

Additionally will any 1/16w resister with a 5.1kΩ resistance work to replace R7911?

[poisonite]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

Also, i forgot to mention that i measured R7305 and it reads 5.10v dc on both sides.

[piernov]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

There may be other issues, but yes putting back R7911 is the next step towards fixing the board.
You need a 5.1kohm resistor in 0402 package. (it should also works with a bit higher or a bit lower resistance)

[poisonite]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

There may be other issues, but yes putting back R7911 is the next step towards fixing the board.
You need a 5.1kohm resistor in 0402 package. (it should also works with a bit higher or a bit lower resistance)

I've ordered a replacement resistor as well as a replacement for the commonly faulty capacitor mentioned earlier. I'll update after i've replaced both components.

Thanks again!

[poisonite]

Re: MacBook Pro 2010 15in 820-2850 A Unresponsive

There may be other issues, but yes putting back R7911 is the next step towards fixing the board.
You need a 5.1kohm resistor in 0402 package. (it should also works with a bit higher or a bit lower resistance)

Hi, I finally got the parts soldered on and now the fan turns on low for about 5-10 seconds and then turns off and a few moments later repeats in a loop. Any idea what this means?