acer 5750g short on B+

[dellxps15]

hi, even if i found some thread with similar problem, i see the thread owner give up in bypass b+ short by removing battery usage and use only dcin voltage, so i decided to start this new thread with that problem.

after removing pr14 i see short only in right side (B+). to try to spot some bad component, i proceded in removing L22 and short was still in the b+ side.
i had also short on pin 20, but after clean pr14 pad with goot wick short disappeared on pu1 pin 20. then i removed pl3 and short was still in B+.
i removed also pq5 and short is still there. removed pu1 and still short , removed the 2 0808 caps near l22 and still short, so as i assume short is in pc188 or pc189.


i show a picture of board with component, without component and with green and red. green means no short, while red means short is present.

what can i do if short is on mainboard ? i think to make some little board with those component in it and then attach to mainboard with some thin wire to the corresponding place and order.

the green line in pr14 goes to pin 20 of pu1 so this can be resoldered without problem by just apply some solder mask in the upper and lower pads.

cant find the pc188 pc189 location to see if problem is there.

anyone got a .brd for that mainboard ?

edit: see now pl24 anso have B+. goind to remove it and see if short disappear

omg, B+ rail is everywhere....

edit2: ok, removed pl17, pl15, pl13, pl24, still short. was giving up and wait to buy a lab psu, but then after removing pl7, short disappeared

i think now im near to discover the bad guy

edit3: and the winner is.... pc56 or pc57, as after remove pq30 still short. after removing one of these cant know exact name as no value in the board, but they have same value and now i know what was causing the short.

[GallegoT]

Re: acer 5750g short on B+

Hi,
I'm having same problem than yours, short in B+.
Also when I remove PL7 I get short only in one of the sides (pin 1) and goes out from the other side (pin 2). Then I removed Pc56, Pc57, Pc172, and Pc173, but short is still there. I removed Pq30 and Pq31, but still short.
Still looking for the shorted componet. Any advise will be welcome.

Thanks for your post and regards.

[polytek]

Re: acer 5750g short on B+

Hi dellxps15,
i have seen the same problem with this mobo, i have removed all B+ coil; all b+ capacitor, the short diappear, but when i reslod the compononent the short come back, i think it's a pcb layer problem, specially when i use hot air to soldering mosfet and small cap, the layers got short,
i have not a power supply lab, to inject voltage for each section and see what section is causing the short, but if you can do this it's the best method.
also board view can help for this, but i have seach on google and there is no bdv.

[GallegoT]

Re: acer 5750g short on B+

I think I found the problem. Waiting for componet to test but PQ31 or PQ32 is in sort. So in this board, and for the moment PQ7 shorted and changed and PQ31 or 32 Shorted.
With those componets out I have not shorts on B+ Rail. I'll post after the final test.
Thanks for your clues.