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W520 170W AC Adapter / PSU Repair

Posted: Sat Oct 26, 2013 4:45 pm
by malxces
Few days back my 170w AC adapter got fried due to high voltage (very bad smell). I dissembled it in hope to replace burned electronics component, unfortunately components are burned too badly to be identified. I was able to figure that,

1. Two component got fried (i think)
a) A ceramic Capacitor
b) UNKNOWN

Image

See all Pics in Hi Res here: http://imgur.com/a/uxHJm

I am hoping if anyone having this PSU can help me identify those components by opening your PSU and reading values
or something.... may be few snaps of yours.

Regards.

Re: W520 170W AC Adapter / PSU Repair

Posted: Sun Oct 27, 2013 2:05 am
by BillMorrow
hello and welcome to the forum..

while I admire your intention to replace the dead components if I had suffered the same disaster I would head right to ebay and find a replacement.. a genuine Lenovo replacement rather than an "after market" replacement even though those might work as well as the OEM version..

as for repairing your damaged unit I think there might be more than the obvious wrong..

but I could be wrong.. :)
lets see what other forum members might have to offer..

Re: W520 170W AC Adapter / PSU Repair

Posted: Sun Oct 27, 2013 12:44 pm
by jcvjcvjcvjcv
Are you sure that the unknown has just two legs? Not a four-legged rectifier?

Also: is there still a fuse in there?

A side-note: high-resolution pics that are out of focus won't help. Better focus right, then crop.

Do you have something that's focussed right with the area shown in picture 28?

Are there still markings on the PCB of the missing components?

Re: W520 170W AC Adapter / PSU Repair

Posted: Tue Oct 29, 2013 1:27 am
by malxces
@Bill
Thankyou for having me as a member of your forum.
That is indeed a choice for me to buy a new one from ebay but its a second one since i hav a 90W adapter of my T61p and its kinda keep me going for now (offline charging). Secondly buying from ebay is a bit difficult for due to my location ... (paypal not availble here etc)

Yes you can be right regarding "obvious wrong" thing but i was hoping to first fix the obvious and see if that work ... may be the burnt components saved the others in circuit.
(it may be a bad logic though :) )


@jcvjcvjcvjcv
a) could not locate a fuse
b) I will try to get a better focused pic for you of 28.
c) pcb area is burned badly and as i tried to remove burn marks it removes the green coating too... so no markings.

d)yep UNKNOWN has 2 legs not four.

Re: W520 170W AC Adapter / PSU Repair

Posted: Tue Oct 29, 2013 2:55 am
by malxces
Few more angles [Originals]: (can not focus better)
http://imgur.com/a/LIOey


Few more angles [Labeled]:
Image

Re: W520 170W AC Adapter / PSU Repair

Posted: Tue Oct 29, 2013 3:00 am
by BillMorrow
no paypal in Pakistan..?
not so easy to buy from ebay then I agree..
darn it..

but I still have concerns a repair will be difficult..
with the burned PC board and the fact those AC adapters are switching power supply's..

is there any other way to send funds out of Pakistan..?
maybe swap a nice magic carpet for a new ac adapter..? :)