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820-00165-a no power F7140 short

L

lincev

Member
hi sorry but I have another board with problem power

I have led green and orange but F7140 is broken with PPBUS_G3H short to ground

I have checked C3080 and it is fine but I don't know how I can check Q5500 or Q3080.. and a resistor I don't think is the problem...

can I help me?

thanks !
 
2informaticos

2informaticos

Administrator
Staff member
What is the exact resistance to ground (ohm scale) at PPBUS_G3H?
Compare with the readings on all big coils.
 
2informaticos

2informaticos

Administrator
Staff member
So you don't have short between PPBUS_G3H and any secondary coil?
Then is safe to use voltage injection method.
 
L

lincev

Member
If I have checked again and all the coils are correct, I inject 3v then into pin2 PPBUS_G3H of the F7140 fuse and search with a thermal camera,

thank you
 
L

lincev

Member
ok short is C7371, I have changed this part, I don't have a short to ground, now I connect magsafe and I have green led orange led but no fan, reset smc responds and led changes, in bypass mode does not work either.


What measures do u need to continue? thanks !
 
2informaticos

2informaticos

Administrator
Staff member
Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L (at same time).
If detected, check for pulse at PM_SLP_S4_L.
 
L

lincev

Member
PM_PWRBTN_L= 1,6v trigger SMC_ONOFF_L drop pulse at 0v

PM_SLP_S4_L= 0v all time with/out trigger SMC_ONOFF_L
 
L

lincev

Member
PP3V3_S5=3,30v 1,50v 0,40 0 all time changing
PP3V3_SUS=0v
P3V3SUS_EN=0v
PP3V3_SUS_FET_R= 0,20v 0,50 1,08v all time changing (If I disconnect MagSafe several times I get this measurement, otherwise the value is 0 directly)
 
2informaticos

2informaticos

Administrator
Staff member
I saw weird issues with the fuse, after found short on output side.
It may have internal fracture, wich is noted only with power applied.
 
L

lincev

Member
is the best ! Sorry for my lack of experience, I replaced it and it works!

But I have a new problem, the battery is detected and the charge rises without problems but when I disconnect the charger it turns off... why?

I add that I have tried a new battery and the same result. very thanks !
 
L

lincev

Member
r6950 value is "normal" scale 20k 9,93 and other board 9,78 ohms and check C6950/1, D6950 my board don't have this item

J6950 is nice any pin bent (internal connector) or broken pins (external)

any ideas? thanks
 
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