820-2914 death

Dozer

Member
hello. i am just working in that board 820-2914

it is not turning on.

pluging in the macsafe the green light is coming short, then off. After 1,5seconds again short green, off.

I removed F7040and 7041. After that I had a flickering green light

the 12.6V are not stable, coming up then down to 0 and so on

I replaced U7000 2 times. On Q7035 pin 4 pulses are nice
on Q7030 its not stable

U7000 Pin 28/29 is 20Ohm

R7010/7011 is ok, R7051/7052 is ok

Q7080 replaced


I have red probe on ground with a good working board on D7005 Pin1/2 infinity, on this death board I have some like 1.080

Now the intresting:

If I hold the front end of the solder iron on pin 1 of L7030 then I have on Pin 2 L7030 12.54V not changing, green light is constant as well. If I take it back(the solder iron) green is flickering and Pin 2 L7030 is changing from 12.6 to 0.


need help please.
 

turbo

Member
hello. i am just working in that board 820-2914

it is not turning on.

pluging in the macsafe the green light is coming short, then off. After 1,5seconds again short green, off.

I removed F7040and 7041. After that I had a flickering green light

the 12.6V are not stable, coming up then down to 0 and so on

I replaced U7000 2 times. On Q7035 pin 4 pulses are nice
on Q7030 its not stable

U7000 Pin 28/29 is 20Ohm

R7010/7011 is ok, R7051/7052 is ok

Q7080 replaced


I have red probe on ground with a good working board on D7005 Pin1/2 infinity, on this death board I have some like 1.080

Now the intresting:

If I hold the front end of the solder iron on pin 1 of L7030 then I have on Pin 2 L7030 12.54V not changing, green light is constant as well. If I take it back(the solder iron) green is flickering and Pin 2 L7030 is changing from 12.6 to 0.


need help please.
what is ohm measurement on pic 17,18 take out fl7040 and then measure voltage ...... post result
 

Dozer

Member
Resistance over
C7020: 21.1 ohm
C7050: 3.8 ohm



all measured with removed F7040/7041
 
Last edited:

dukefawks

Administrator
First need to get a stable green light. Remove Q7030 and see if that gives stable light. If yes then replace Q7030/35
 

Dozer

Member
removed q7030, but still the same, not stable.
removed q7030 and q7035 no change

The mag safe is ok, tryed on another macbook the green light is ok.

is it possible that the problem can come from the smc?

but the pin 13 (u7000) is stable high

turbo pin 17/18 has the same downspikes
 

Dozer

Member
no the same spikes sown to 0

but i found the same spikes down to 0 as well on F6905

so in my opinion the problem ist not around u7000

should be a problem in the one wire. or?
 

Dozer

Member
sorry i just doubleckecked

3.48V present and stable
SMC_RESET_L stable now as well
CHGR_RST_L is stable 3.48V
 
Last edited:

Dozer

Member
i pulled out F7040/41 and inject now directly 12.54V to system

and i pluged in the magsafe, 3.48V are there, problem is still the same

found R7015 in schematic 330K on the board only 152K. I replaced it but still same problems, i think i am going to replace again the u7000
maybe u7000 was in trouble because of the low resistor

replaced, but still same problem :-(
 
Last edited:

Dozer

Member
in diode mode i have red on gnd and black on PPDCIN_G3H I get 1.071
on every other board i get infinity

now i pulled all out one after the other by measuring red on ground and PPDCIN_G3H

L6995
U6990
D6990
U6900
D7005
U7000
Q7080 !!! infinity

tomorrow i will put back one after the other and report back.
 
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