ASUS motherboard blown TVS diode?

[rockxstar89]

Re: ASUS motherboard blown TVS diode?

I'm terribly horrible at reading these schematics..
Heres a macro and enhanced view of both the front and back side of the burnt out area of the board... Maybe this will help with identifying the part.

[felon637]

Re: ASUS motherboard blown TVS diode?

I have the same problem here. I was running a third party power supply (antec 65w universal adapter) and when the girlfriend plugged it in it sparked and left a burning smell.
I took it apart to find the very same component burned out, and am pretty sure it's a TVS diode. Mine was actually charred enough the silicon blew right off and I could see its innards without the insulation.

I was running the laptop off of battery, however it was slowly dying. Didnt get a chance to run a full diagnostics, however it seemed as though it would run off ac. It was running off battery with the power cable plugged in, but it was not charging the battery, and any time I removed the power cable it shut off.

I have a friend who can do the repair work for me, but I need to know parts first.
Should the diode be replaced??? obviously it served some purpose, had some type of current running through it if it burned out the way it did.

felon have you had any luck procuring a power controller?
or getting your laptop to work for that matter??

I think the power controller is part of the processor.

It that is the case I will just put a new motherboard in.

Maybe someone will chime in if it is part of the processor.

[rockxstar89]

Re: ASUS motherboard blown TVS diode?

I think the power controller is part of the processor.

It that is the case I will just put a new motherboard in.

Maybe someone will chime in if it is part of the processor.

I wouldn't think that Asus would piggy back such a task onto the processor like that...

And the fact that this component was the first thing to go in both our mobos in the case of a power spike makes me want to believe it was acting as a fuse of some sort to protect the board in this very situation...

it would be really nice if someone with a working Asus k50i v2.3 mobo could identify the part for us though.. I tried looking up a PC of the board online to see if I could make out the chip but to no luck.

[rockxstar89]

Re: ASUS motherboard blown TVS diode?

I think the power controller is part of the processor.

It that is the case I will just put a new motherboard in.

Maybe someone will chime in if it is part of the processor.

I wouldn't think that Asus would piggy back such a task onto the processor like that...

And the fact that this component was the first thing to go in both our mobos in the case of a power spike makes me want to believe it was acting as a fuse of some sort to protect the board in this very situation...

it would be really nice if someone with a working Asus k50i v2.3 mobo could identify the part for us though.. I tried looking up a picture of the board online to see if I could make out the chip but to no luck.

[felon637]

Re: ASUS motherboard blown TVS diode?

I wouldn't think that Asus would piggy back such a task onto the processor like that...

And the fact that this component was the first thing to go in both our mobos in the case of a power spike makes me want to believe it was acting as a fuse of some sort to protect the board in this very situation...

it would be really nice if someone with a working Asus k50i v2.3 mobo could identify the part for us though.. I tried looking up a picture of the board online to see if I could make out the chip but to no luck.

keep me posted

[heavymachines]

Re: ASUS motherboard blown TVS diode?

Here is exact issue enjoy its a diode here is the link http://www.laptopish.com/89/asus-k50...d-replacement/ he does not replace the diode just replaces the motherboard but this should help you get on right track but i would check that power mosfet and make sure its not shorted seems to be common to short due to power spikes and seems to happen most with aftermarket power adapters, i had same exact issue with a Toshiba c655d few weeks ago and luckily all it took was the power mosfet , when i replaced the fet i used a higher rated one to handle the spikes from the aftermarket adapter better so far been solid and no issues....


also the diode is marked b-4 good luck fellas

[heavymachines]

Re: ASUS motherboard blown TVS diode?

also here is the more info on that diode "SS0540 Diode smd code "B4" and here is the link to the data sheet http://www.alldatasheet.net/datashee...TE/SS0540.html its a "SURFACE MOUNT SCHOTTKY BARRIER DIODE"

but diffidently check that neighboring power fet to make sure it did not cause this diode to blow it will have source and drain and there cannot be any kind of short or it will keep blowing that diode....this should be a fairly easy fix fellas.....

[rockxstar89]

Re: ASUS motherboard blown TVS diode?

You sir have just made my day, err night. thank you very much.

[rockxstar89]

Re: ASUS motherboard blown TVS diode?

Here is exact issue enjoy its a diode here is the link http://www.laptopish.com/89/asus-k50...d-replacement/ he does not replace the diode just replaces the motherboard but this should help you get on right track but i would check that power mosfet and make sure its not shorted seems to be common to short due to power spikes and seems to happen most with aftermarket power adapters, i had same exact issue with a Toshiba c655d few weeks ago and luckily all it took was the power mosfet , when i replaced the fet i used a higher rated one to handle the spikes from the aftermarket adapter better so far been solid and no issues....


also the diode is marked b-4 good luck fellas

if we choose to upgrade our fets, what would you recommend?

[heavymachines]

Re: ASUS motherboard blown TVS diode?


here is the data sheet for the current mosfet that on the motherboard right now. The full model number is "ap4835gm" its ever slightly different then the one on the Toshiba i worked on , the toshibia's fet had 4 source and 4 drains, this one has 3 source 1 ground and 4 drains, i will have to do a ton of researching to find out what higher rated compatible fet will work...question is can you test it for shorts for me? now that you have the datasheet to know how to test it, you want to make sure there is no shorts of any kind between source and drain pins if there is no shorts then you most likely do not need to "upgrade".


also want to note felon has a fairchild brand fet and rock has advanced power brand will do more research on the 2 fets most likely they are same spec's just different company will verify later its real late tonight i need to go to bed have to work in morning....

[heavymachines]

Re: ASUS motherboard blown TVS diode?

to prevent it blowing the diode again if the mosfet checks out you should be able to install a 4 er 500 ma fuse or just keep it the way but if it works for awhile and blows that diode again there may be a need to do some modding er upgrades. Can you point out where exactly power comes in at having a hard time telling exactly where its at...i think i see the bottom side of the pins right above where it fried but not 100% percent sure...

[felon637]

Re: ASUS motherboard blown TVS diode?

You are awesome! Thank you very much.

[heavymachines]

Re: ASUS motherboard blown TVS diode?

You are awesome! Thank you very much.

you guys are very welcome glad i was able to help....

[ClkWrkOr]

Re: ASUS motherboard blown TVS diode?

i'm sure this is "a day late & dollar short", since i have the same board .."not burnt" a b4 pic

[rem_11]

Re: ASUS motherboard blown TVS diode?

i'm sure this is "a day late & dollar short", since i have the same board .."not burnt" a b4 pic

Where do you buy this diode?
I have the same problem. No power on, no lights. I can replace them to try to make the laptop.

Thanks for your answer

[Duncanbest]

Re: ASUS motherboard blown TVS diode?

b4 ---> SS0540

http://www.digikey.com/product-searc...=0&pageSize=25

[rem_11]

Re: ASUS motherboard blown TVS diode?

b4 ---> SS0540

http://www.digikey.com/product-searc...=0&pageSize=25

Thanks, today i buy one. I let you no of it works and fix my problem.

[d_mo]

Re: ASUS motherboard blown TVS diode?

i have the same problem. did the diode replacing work?

[vinkos]

Re: ASUS motherboard blown TVS diode?

Not working for me i replace diode B4 (blown) but my laptop
is working as before !
Means does not charge battery !
Any ideas what is responsible to prevent laptop battery to charge ?