Re: Macbook pro A1278 green light but no power
mean all these lines are shorted if it is ohm.
mean all these lines are shorted if it is ohm.
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Re: Macbook pro A1278 green light but no power
guess thats bad,, is there a chip that could be badComment
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Re: Macbook pro A1278 green light but no power
i have no volt at L7260 or L7220 eitherComment
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Re: Macbook pro A1278 green light but no power
no i dont but i can pic one up todayComment
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Re: Macbook pro A1278 green light but no power
normally for each line shorted you need to find all IC (on that line) , remove them one by one till find the one (IC) , who bring short to the line
.Comment
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Re: Macbook pro A1278 green light but no power
ok and ill try to pic up a sd card for my microscope so i can take a pic of U7200 for you it looks bad and so does everything around it.. this logic board was shutting off and on when i got it but was running had water damage around the U7200 so i ultrasonic cleaned it .. yes i have a good one and i have cleaned lots of boards but this is the first one that was running before i cleaned it and now its notComment
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Re: Macbook pro A1278 green light but no power
with power supply you need to set voltage at 2.5v 2A apply to the 5V and 3V lines shorted until the bad components start heatingComment
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Re: Macbook pro A1278 green light but no power
ok thanksComment
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Re: Macbook pro A1278 green light but no power
to start macbook needs 12.5 volt, 3.42 volt and 3.3 volts.
check if these voltages are presentsComment
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Re: Macbook pro A1278 green light but no power
Thanks i have no 3.3 volt railComment
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Re: Macbook pro A1278 green light but no power
3.3 volt rail is supplied by u7200 that u say is bad, so
1st make a picture of it
2nd measure "vin" and "en" point reading the schematicComment
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Re: Macbook pro A1278 green light but no power
en pin 13 is 3.02
vin pin 16 ... the numbers dont stop jumping around
sorry my phone dosent take a good enough pic ..Comment
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Re: Macbook pro A1278 green light but no power
"the numbers dont stop jumping around " what do u mean ?
pin 16 must have 12.5 volt
if no pin 16 voltage, not stable 12.5 voltage, no 3.3 volts on L7220 replace u7200Comment
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Re: Macbook pro A1278 green light but no power
had to wait for the chip to arrive changed it and it works great thanks very much merry christmasComment
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Re: Macbook pro A1278 green light but no power
Symptom: Green charge light, turns amber to charge battery, stays green when no battery. No power up.
OK I made some measurements:
SMC_RESET_L: 3.43v
SMC_PM_G2_EN: 3.47V
S5_pwrgd: 3.3v
diode checks (red on ground)
PPBUS_G3H .438 = 12.57V
PP3V3_S5 .362 = 3.3V
PP5V_S5 .484 = 5V
PP5V_SUS .376 =5V
PP3V3_SUS .297 = 3.3V
PP3V3_S4 .352 = 0.5V
OK so I'm looking into that last one. Looks like my model is the K90i MLB variant.
PP3V3_S4 is controlled by Q7800 and Q7802 FETs - those both check out.
BUT Q7802 gate is being held low, making it inactive. The signal that controls that is P3V3_S4_EN
P3V3_S4_EN is controlled by PM_SLP_S5_L. This is low but it needs to be high for the system to run. That signal is controlled by the giant U1800 Cougar Point CPU.
Anyone have any ideas on where to go from here?Last edited by audiomodder; 12-25-2017, 02:02 AM.Comment
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Re: Macbook pro A1278 green light but no power
ah looks like PM_SLP_S3_L, PM_SLP_S4_L, and PM_SLP_S5_L are all low. So I really suspect Intel Cougar U1800 is not working right.
I got low on PM_PCH_PWRGD, and also on SML_PCH_0_CLK
also I hear a faint clicking sound and green light only happens 1 out of 3 times...tried 2 different chargers and same thing. It seems like the green light is finicky :/
any help greatly appreciated!Last edited by audiomodder; 12-25-2017, 03:40 AM.Comment
u7200 ?
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Hello again,
got an MacBook Pro from 2015, model A1502 and motherboard version 820-3476-A.
Device died over night on charger.
Currently I did the follow things:
1. Checked visuell the board, test with another MagSafe-Charger and with another DC-IN-board too
2. Measured 16,5V on PP18V5_DCIN_FUSE but 0V on ADAPTER_SENSE and 0V on PP_3V42_G3H and 0V on PPBUS_G3H but 16,5V goes to U7090
3. Because of corrosion and bad resistor values I changed these components: U7090 / C7094 / C7095 / R7095 / R7096 / L7095 / C7099 -> But further... -
Hi, I have a MacBook pro A1278 (820-3115-B) that has green light on the charger and does not turn on, the fan does not spin.
The voltages in the SMC seem correct. I have made voltages measurements on the main coils and I put their measurements here:
L7220..........3.3V
L7260...........5.12V
L7330..........1.5V
L7030..........12.67V
L3895..........2.5V
L7760..........1.80V
L9701..........0V
In the following coils they give me continuity with ground, which seems strange to me:
L7550,L7510,L7520........ 0V
... -
I am looking at an A2337 and found this for the order of power rails and what they do. Can this be confirmed before I dive into hunting down power rails that do not exist or are not neccisary?
- PPBUS_G3H (12.6V-12.8V)
- This is the main power rail that supplies power to the entire system. Check this rail first, as it must be present for other power rails to work.
- PP3V42_G3H (3.42V)
- This power rail is derived from PPBUS_G3H and is used to power the SMC (System Management Controller) and other essential circuits. It should be present if PPBUS_G3H is working correctly.
- PPVRTC_G3H (3.3V)
- This
- PPBUS_G3H (12.6V-12.8V)
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I have a 13 inch MacBook Air 2017 that does not show any life, however, there is activity from the MagSafe light going from green to orange and staying. Normally, this battery works perfectly fine and it can actually charge the battery as if I were to leave it alone it would change to just green, however, this thing does not boot up at all, I was told the computer was at 30% and then it randomly shut off.
Some voltages:
PPBUS_G3H - 8.5V
SMC_PM_G2_EN - 3.42V
PP3V3_S5 - 3.32V
PP3V42_G3H - 3.42V
PPDCIN_G3H - 15.18V
PP5V_S5 - 5.04V
PP3V3_S5_REG_R... -
So Ive got a Macbook Pro here with no power or charging light.
I have taken the board out and did an inspection and found a small bit of water damage on C1267 (PP1V05_S0). Cap fell off as I cleaned the area but I dont think this is responsible for my no power or light issue, and should probably work just fine without it.
So after watching a few Louis Rossman videos and some post here with similar issues, Ive done a lot of testing and have found the following values of the main lines I think are important:
PPDCIN_G3H = 16.63V
PP18V5_DCIN_FUSE = 16.63V...
Comment