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MacBook Pro A1502 820-3476-A 2014 - NO DISPLAY

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Bockas

New member
Hello dear friends!
I bought Macbook Pro 2014 from ebay that was dead, there was missing D7010 and there was no green light on charger, after fixing that there is no chime i'm not sure is sound working or not, also there is a short circuit on battery rail, but that is also not my main concern....

There is no display, I have output on HDMI out and device is working properly (without sound and battery) but screen doesn't turn on.
I have measured 52 V on
1PPVOUT_S0_LCDBKLT

5V on
28PP5VR3V3_SW_LCD

I will measure resistance and voltage drop on every pin of J8300 today.
I replaced this - U7700 U8330 U8300, C8352.
Any advice where should I look next?
Also can you replace PCH with just hot air station or you need BGA station?

Thanks in advance.
 
2informaticos

2informaticos

Administrator
Staff member
First of all, welcome to the forum!

52V on backlight output, denotes open circuit to the LEDs strip.
Check J8300 first and test with known good compatible LCD assembly.

Do not try to change a PCH without proper equipment (BGA rework station).
I hope you don't want to change it on this board.
 
B

Bockas

New member
Hi,


motherboard works fine on hdmi output, so I suppose that PCH is fine.
Under the microscope I saw that screen connector is damaged, in diode mode while testing connector I measured some 0.09 OHM-s that I'm worry about, how to test the screen, do you know what should be the measurement on screen connector pins on diode mode (red on ground ?) or in ohms?
I'm just starting so I have parts for few older MacBooks.
LP133WQ1 SJ E1 DCN441406G1FF0H0 LGD 133DA51903DJF 913B are the numbers on the screen.
 
2informaticos

2informaticos

Administrator
Staff member
"in diode mode while testing connector I measured some 0.09 OHM-s"
Where did you note such low values?
Switch to ohm scale, instead of diode mode, for very low resistance.

Replace LCD connector, if looks bad.
It could be the culprit and nothing else damaged.
 
B

Bockas

New member
Tomorrow I will buy new cable, and I will replace J8300 before testing new cable, I will let you know what happens!
I got sound working so only problem will be short in battery circuit if screen is working.

Thank you so much this is best forum ever, fast reply with good advices so awesome.

If I will have troubles detecting short in battery circuit I will let you know.
Any known problems when battery shorts the mobo?
 
B

Bockas

New member
Şcreen is working properly after replacing screen cable! I'm so happy, last thing left is problem with battery, if you plug in battery when laptop is working it shuts of, if you connect charger while battery is connected green light is blinking rapidly every second, it blinks green, what is the problem?
I hope not dead smc, wish battery is dead.
Device is working properly withouth battery.
 
B

Bockas

New member
Withouth battery PPBUS_G3H drops from 19,85V to 5V. With battery max 9V and drops to 5 V and shuts on of on of
 
B

Bockas

New member
When I replaced 7130 no fan spin anymore PPBUS_G3H 2V, replaced it again now not green light on charger, did i blew caps near it? How can I test it
 
2informaticos

2informaticos

Administrator
Staff member
Be sure R/C7125 are good, or Q7130 will burn again.

Use R5115/16 pads, instead of power button; for testing purpose.
 
B

Bockas

New member
Q7130 blew again i think same blinking green light, but it was charging but couldn't turn on with another Q7130
 
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B

Bockas

New member
C7125 after replace same value, 0 resistor also

In diode mode on q7130
2 blackPPDCIN_G3H_CHGR
6 redCHGR_LGATE
0.102


1 redCHGR_UGATE
6 blackCHGR_LGATE
0.121
 
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B

Bockas

New member
18V unstable, it drops from 18V to 5V and goes back to 18V again withouth battery, with battery is max 9V and drops to 5V, blinking green light on charger was device turning on/of rapidly, Q7155?
 
2informaticos

2informaticos

Administrator
Staff member
If you get 18V at PPBUS_G3H, Q7130 is shorted again.

You've said the board worked without battery.
That is not possible with fluctuation 5-18V.
Change Q7130 and U7100 at same time.
Be sure to get good solders and check traces continuity.
Just in case, change C7125; it can't be checked in diode mode.
 
B

Bockas

New member
I have 2 pcs of q7155 1 one 0,410 voltage drop, second 0,464 third one was shorted on board, whatt should be the reading?
 
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