Experience fixing asus 96j charger circuit?

Asus 96j laptop probably had 3rd party charger (correct voltage/amps) plugged in backwards (unkeyed multi-head plug -- bad news). Burning smell led to unplugging (good). Laptop worked fine on battery until it ran down, and not surprisingly won't charge now. Asus 96j disassembly/assembly is available on web.

1. Anyone have experience disassembling to see motherboard, and successful reassembly?

2. Anyone have experience fixing charging circuit (e.g. replacing burnt voltage regulator, if that's what it turns out to be)?

3. What about motherboard circuit diagram?

 

You're better off contacting your reseller (if you purchased it from one) and ask for help on this....

 

I doubt the resellers would know either. This is board level repair, information that only ASUS has.

 

I just contacted asus about this issue with my V6J (just blinks orange battery indicator led), asked for technical mobo specifications, but they just replied saying its confidential information. But I noticed that when i opened up my laptop, the DC jack is on a seperate PCB from the Motherboard that is removable. I am hoping that this is the problem and that i can just replace this for 6$ from Asus's estore at estore.asus.com

 

BTOTech does some board-level repairs in house - contact Eddie to see if he might be able to help if you send it to him.

 

ClearSkies, thanks, I'll try that.

eatbuckshot, I wonder if S96J also has charging circuit on a separate PCB. What is the minimum disassembly you were able to do on your V6J to expose that PCB? And at that point is the separate PCB removable? My main concern is to do the least disassembly and reassembly possible, since the laptop itself is working now, and I don't want to make it less working due to my mechanical errors (I'm fine with electronics but I don't want to drop a screw).

Also, I looked on estore.asus.com and didn't see your part or anything for $6. Can you tell me the exact part URL because I want to see what your separate PCB looks like, to compare with what I may see.

Thanks for everyone's help here!

 

I actually had to disassemble most of it, almost all the screws..

 

Did you have to disconnect or remove any components? E.g. did you have to disconnect the screen or keyboard, or remove the CPU?

I'm hoping not, but interested to know what I'm getting into ...

 

i have to disconnect the keyboard, but that's really the easiest part. I had to unscrew 2 screws for that and just disconnect the cable. I don't have to remove the LCD or cpu

 

That sounds promising. I'll see if it's that easy for me. BTW, regarding polarity for the DC socket, unlike my IBM, it's not marked on the outside and I don't have the original charger either.

While there's no guarantee that your model's polarity is the same as the S96J, what is the polarity on your socket? Is it center plus or center minus?

 

unfortunately i'm on vacation with my family and i forgot to bring my multimeter along with me as i was trying to fix my laptop... I actually got a note that said my luggage was opened and was checked for security precautions as i brought screwdrivers, wire cutters, and a 100ft spool of 18 gauge wire .lol. but newho can't tell you that right now

 

guys the recepticle for the dc plugin is the least of your worries, the charging circuit is on your mb, i fixed mine in my last asus, we had to remove the mb completely, i cannot say where they are located on your board, but i can tell you this. there is an entire series of VR's that are used to complete the charging process, there is a chip that is polarity sensitive as well that i guarantee you is burned out. we had to unsolder all the broken vr's and replace that chipset. (believed to be a monitoring processor controller etc) we also had to id an test the entire circuit under a microscope, we had to reverse engineer the charging circuit as asus would not provide the info. we found a flaw in the circuit as well, we changed it on mine. our solution was a .25 cent diode we put in line after the dc in. it senses polarity and shuts of the dc in until it is hooked up properly. asus tech requested the info from us and was shocked that we could figure this out. we sent them the motherboard and let them try it out. they acted dumbfounded, called me at home, wanted to know who we were. i thought they would take our advise and change the way they made the charging circuits but i guess they didn't do anything with the info. they are aware of this problem though, it happens more than you think. everytime a universal charger with changable heads is plugged in reversed polarity it burns out this circuit. it amazes me. it is not an easy fix. we are an aircraft restoration business and design our own pcb circuit boards otherwise i think it is out of most people reach, it took a lot of research to accomplish. (as well as my electrical engineer) i recall about 6 items were toasted is a split second, i would have to dig up the emails between us and asus to id them, which we did. their model numbers, purpose and positions. if i were you, i would send it back to asus in california and tell them it is not charging any more and leave it at that, they will just replace the mb in a matter of days, if they give you crap, saying it is your fault, tell them no, it is their fault for not designing in circuit protection for the charging circuit. i think they would have had to recall, like all their notebooks to fix this simple problem. to me a 25 cent part is a small price to have to pay to rectify this situation for furture notebooks. it is not like this has not been broght to their attention. i assure you if you stand firm, don't lie when asked, what happened you will fair best. after working with this first hand, i guarantee you they will go right to the charging circuit regulators and figure it out right away. good luck but i wouldn't bother tearing your notebook apart just to find out that it has to go in to asus.

 

you accomplished what i wanted to do, i lack the electrical engineering knowledge and equipment to do this, i congratulate you!
teach me now

 

Hi fishnpilot,

Well, what you describe certainly sounds logical (I mean your actions and recommendations, not the original asus design). I'm an EE now in software failure prevention, so, yes, a diode for reverse-voltage protection would certainly make more sense than disabling a $1300 laptop if someone plugs a charger in backwards!

I'm still holding out hope that for the S96J (relatively new model that isn't even listed on asus support site) the board that's got the DC socket on it also has the voltage regulators. Like maybe they didn't redesign the circuit (add a diode) but at least they made it easier to replace burnouts.

Have a look at

http://estore.asus.com/shop/item.asp?itemid=3515&catid=481

which is for a different asus model. Click on graphic to enlarge. Sure looks like some chips on the board - any of them look like voltage regulators to you? (I know you can't really say for sure with one silly graphic; I'm just looking for your impression.)

Anyway, I'm pursuing asus service too. We'll see what they have to say.

 

Actually the S96j is controlled by Intel, so if you had any problems with the computer you would talk to the VBI department, not ASUS.