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Old Yesterday, 10:06 PM   #3151
macattack600
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Join Date: Jan 2012
Need info on where 5v rail comes from (No 5v on board)

Quote:
Originally Posted by macattack600 View Post
I have shorted 2008 a1286 MBP 15" update- quit booting

PP5V_S0 =0v
PP5V_S3 =0v
I do however get some voltage from chip ISL6236 directly from some pins , am I supposed to be checking Out1 , Out1 or En1 ,En2?
or chip U7300 TPS51116

There is no water damage
I am having trouble locating the source of where my 5v starts or where it comes from I have schematic and boardview any pm or help a1286 early 2009 MBP 820-2330-A
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Old Today, 01:11 AM   #3152
cpufixer
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Join Date: Apr 2014
Quote:
Originally Posted by macattack600 View Post
I am having trouble locating the source of where my 5v starts or where it comes from I have schematic and boardview any pm or help a1286 early 2009 MBP 820-2330-A
check "power aliases" page, that should get you started. page 8, page 3.
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Old Today, 07:15 AM   #3153
tiagobaracho
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Quote:
Originally Posted by Wuchi View Post
Ok, I'll check.

I just did some measurements. what is this part, and are the voltages looking right or wrong. Is this feeding the 12vdc to battery? Or should it do so? Measurements were taken while mbp is running.
6.5v for the battery is too low... means 2,16 per cell... please check again the two pins... the first(GND and the last on the right (PPVBAT)... If you are really getting 6.5, you battery is probably dead...remember that those solder has a thing layer of varnish and sometimes you need to scratch to get a got measurement ....
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Old Today, 08:31 AM   #3154
Wuchi
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Join Date: Dec 2013
Location: Finland
Quote:
Originally Posted by tiagobaracho View Post
6.5v for the battery is too low... means 2,16 per cell... please check again the two pins... the first(GND and the last on the right (PPVBAT)... If you are really getting 6.5, you battery is probably dead...remember that those solder has a thing layer of varnish and sometimes you need to scratch to get a got measurement ....
I measured it again and it is 6,5volts between first and last pins.
Tried another battery and it measured 7volts. I've not been able to charge these batteries, so I think that is the reason why the give so low voltages.

I disconnected the battery and measured voltage between first pin (GND) and the last pin on the right and it was 13,3volts. That's when the battery is disconnected.

Is there a problem on the batterysense line? The middle pin?

and thank you for helping!
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Old Today, 09:37 AM   #3155
smithtony22
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Join Date: Nov 2012
Hi
did you ever manage to solve this issue? I have same board (820 3115). Been pulling my hair out trying to find what is the cause of this?


Quote:
Originally Posted by ZZZAC View Post
Hi guys i have an 820-3115 board here.
Bassicly the 16.5v DCin voltage fluctuates between 16v and 12v and no matter what i have tried nothing sorted it
Ive tried new Q7080 and new Q7085 but this didnt change, New U7000, Tested almost all the resistors around the U7000's area. Tested almost all the capacitors around the area.

I noticed lastnight when i have a charging IC installed i can hear a faint ticking coming from somewhere. My only guess is this is the source of the problem or why the voltage is fluctuating.


any thoughts would be apriciated
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Old Today, 09:46 AM   #3156
cpufixer
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Join Date: Apr 2014
Quote:
Originally Posted by smithtony22 View Post
Hi
did you ever manage to solve this issue? I have same board (820 3115). Been pulling my hair out trying to find what is the cause of this?
check traces to isl6259 u7000,
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