A1278 820-2936-A L7030 short pin 1 cannot find short

[macattack600]

Hi
I had short on U7000 removed now get green light.
16.9v
3.42v all good. I am getting no PPBUS_G3H unless I remove inductor L7030 with only battery but I should have more resistance to ground then 001 on pin 1 of L7030 if removed right? When I solder new U7000 I get dim light .

I remove L7030 find short pin 1 since L7030 removed, I can get voltage now through with the battery up to pin 2 L7030

Q7085 source pins 16.9v when I check voltage pin 4 gate the voltage drops and kills light on magsafe I have to replug. No voltage on Q7080 or R7020 checked all caps and resistor CHGR_CSI_R_P, CHGR_CSI_R_N seem good I just check with resistance on board and to ground.

Pin 12 U7000 3.42 C7005 I get DCin good. I take mosfets off Q7085 Q7080 and test diode mode seem ok then put back on

I notice no 5.1v on PP5V1_CHGR_VDD ,PP5V1_CHGR_VDDP resistor R7001

Where should I look now? Is maybe problem in CHGR_PHASE via line? or maybe battery shielding pin maybe or BIL connector? Thank you.

[dellxps15]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

remove q7030 and q7035 and see if short disappear.

[aanan]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

check c7039,c7030 c7031 c7035 c7036 c7037.

[macattack600]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

removing Q7030 and Q7035 make short not disappear , is it possible CHGR_PHASE -via- is burned because on top of U7000 there was burn hole pin 23, I try to get needle tip probe into second via hole stemming from pin 23 u7000 and get no continuity to removed Q7034 (and Q7030 removed) drain PCB pad .

[macattack600]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

How do you check C7039 it's not there no stuff what is that? resistance to ground I get nothing on pin 1 but do on pin 2 . I check all caps c7030-c7037
in circuit with resistance right? they tested good I think ? I should get higher on meter if good right ?I can only check if caps if L7030 gone.

check c7039,c7030 c7031 c7035 c7036 c7037.

[dellxps15]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

removing Q7030 and Q7035 make short not disappear , is it possible CHGR_PHASE -via- is burned because on top of U7000 there was burn hole pin 23, I try to get needle tip probe into second via hole stemming from pin 23 u7000 and get no continuity to removed Q7034 (and Q7030 removed) drain PCB pad .

post high quality picture of that are with visible burned zone.

[macattack600]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

I have not good camera at the moment. There is actually no burn zone (thought it may have burned inside board maybe not) just on top of ISL pin 23 it pulled pad 23 when I desolder, do I have have to make pad or jump on 23 to get isl on test circuit fully?

I have resistance now to ground on Q7030 Q7035 removed (with L7030 on) I replace and still no good If I leave Q7030 I have resistance it is low. I notice I get 1v on Q7085 drain and on Q7080 drain R7020 too ( One time it give 16.1v, then no more) I think I need to rework this before I ask for help , how can I check caps 100% with only multimeter ? I think I need in circuit LCR .

Could there be short in no stuff C7039? Sorry I take long time to get back thank you!

[macattack600]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

Ok I rework ISL jumping via to pin 23 (no burn just pulled pad) I put all back together and no light at all not even dim then I take off Q7030 nothing , I put back Q7030 and remove Q7035 then I have solid green light! Now PPBUS_G3H is at 16.6v? I check and change L7030 2x -pin 2 is still 16.6v , I thought from parts board I had good Q7035 but maybe it's no good too? Disregard previous post #7.
Do you know where supplier is for Q7030 q7035 besides donor? Or do I have more problem? Thank you.

[dellxps15]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

check resistance on q7035 pins if there is any short present. if no short change q7035, if there is a short post back wich pins has short to gnd.

u can buy easly from ebay or mouser or digikey.

[macattack600]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

Sorry I wait so long to get back I waited for parts I had to get comperable Q7035 mosfet mouser does not carry schematic mosfet this what mouser said instead to buy I don't know if right http://www.digikey.com/product-searc...568-11376-1-ND it fits.

I got the parts I replace both mosfets I get voltage to climb up from -v1.0 to 3.5v on testing on pin 1 L7030 , then if I test source pins on q7030 voltage drops really slowly. I do not have U7000 on I know I solder it right, but it always give dim light so I do all this test with no U7000. The battery give voltage all the way through the machine up to U7000 11.33v (both sides of fuse too) when I check short on meter I get no resistance most everywhere with new fets, (but will read correct battery voltage?), will a motherboard boot without U7000? I have no idea what to do.

Do I have unfixable short on R7039 C7039? What is pulling voltage down? If I remove Q7035 I get 16.9v but this needs to be 12.6v it will not spin fan with 16.9 I have 5v 3.3v too and 3.42v.

[dellxps15]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

check u7000 solder . if u removed it put it back.

voltage on q7035 pins ?

[macattack600]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

3.5v is on Q7035, is my replacement part from digi key look right? Q7035 is without U7000 @3.5v
I press down on U7000 when I solder looks tight ?

[dellxps15]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

for proper solder of u7000, just put some flux and let board get warm till u see solder melting. after that take u7000 and position on the board, but without moving it because it will get stuf because u7000 cold -board warm. after a bit it will move and try to get in place without pushing too much. when u move u7000 a bit and it comes back to it's position is done.

good thing is with a very thin solder iron to pass each side of u7000 with flux and some extra solder. in that way ull see all pins get perfectly.

[macattack600]

Re: A1278 820-2936-A L7030 short pin 1 cannot find short

Thanks bro, I think I give up on this one I know now I solder 3 new U7000 3 times good with micro iron around sides 1st time It get hot like have short when I first get the mac.

Then I redo and get green light and then go dim not hot chip though voltage is negative with no resistance. So much trouble. I think having good LCR to check caps too I'm so tired of pulling resistors and caps to check.

You've helped greatly I learned alot with your help thanks !