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1500 points!! Burned CHIP on laptop motherboard, cannot find anywhere!!!

Posted on 2003-03-11
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Last Modified: 2007-12-19
I have a laptop made by compaq...
one day i decided to replaced the HD, the HD was encased in a cartridge.
when i changed the HD i managed to put the new HD in upside-down!
when i powered it on, it burned a chip on the motherboard right next to the HD
my guess is this chip was responsible for converting or directing power to the HD.

I have gone through every chip manufacturers database i could find looking for something that relates to this chip without luck for about a year now!
i am running out of places to turn and was hoping i might find someone who can help identify this chip so i can order a new one or find a replacement.
i plan to do the solder work myself... this chip is no bigger than a #2 pencil eraser (except its square)

I have pictures of this chip located here:
http://personalpages.tds.net/~csajba/small1.jpg
http://personalpages.tds.net/~csajba/small2.jpg

PLEASE HELP!
If i can get this part identified with 7 days, i will reward the finder with an extra 500 points out of pure happiness. Thats 1500 points available!
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Question by:ViRoy
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39 Comments
 
LVL 8

Author Comment

by:ViRoy
ID: 8116873
DOH!
looks like i cannot make a 1000 point question
youll just have to take my word for it, i will create another question titled with the persons name who answers correctly to reward the points i promised.
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LVL 44

Expert Comment

by:CrazyOne
ID: 8116879
I am curious of tow things. How do you know that is the only thing that has been damaged. And two why not take this machine to a Computer thech shop and see if they can help. Sometimes they have spare boards laying around the for a fee they will sell you the board or so you can part it out.
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LVL 1

Expert Comment

by:brakmat
ID: 8117022
I have three questions.
What is the model of the laptop?
What is the build code for the laptop?
What is the Serial Number?
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LVL 1

Expert Comment

by:sriharish
ID: 8117233
Ok now, this may be he answer- THE Chip looks Socketted means that it can be replaced.Take the laptop to your vendor and he will replace the chip for you, but the chip is costiler.
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LVL 12

Expert Comment

by:public
ID: 8118139
The part is a siliconix dual mosfet Si9936. You can get free samples from siliconix, and have someone to unsolder the old one, and install the new one.
However since this part is a switch, something else in the circuit must have shorted out, and unless the short is remved, the new part may burn as well.
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LVL 13

Expert Comment

by:magarity
ID: 8118751
You can buy these things at your local electronics shop.  Select your locale on this site and it will give you a list of shops:
http://www.vishay.com/mosfets/sales

Hope you're good with a soldering iron and nothing else is burned out that isn't so obvious.
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Expert Comment

by:Salim_Ullah
ID: 8118903
I think its a siliconix dual mosfet Si9936as mentioned earlier one expart. Before going to Replace it You have to Sink all possible charge "locked" other related CKT. unless u do it The chiep will go burn again. Confirm u using correct " Beated" iron and proper temp , Not more then 30 degree c
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LVL 1

Expert Comment

by:brakmat
ID: 8120710
I work on compaqs all the time...I can't do anything for you unless I get the Model, Serial Number and Build Code.
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Expert Comment

by:originalrobby
ID: 8120900
even if you get the chip what are you going to do ?
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Expert Comment

by:RPDC
ID: 8121838
This is a dual line receiver and is availabe from Abra Electronics for $ 0.99.  Their number is 1800-717-2272.  In desoldering the old chip, use some solder wick dipped into soldering flux.  If you do not have soldering wick you can use some copper brade from a coaxial cable that has a copper shield.  This method will remove the old solder without overheating the board and damaging it.
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LVL 8

Author Comment

by:ViRoy
ID: 8122512
crazy: i AM the local computer tech shop! hehe
original: even if i reply to your comment what are you going to do?


mag:  that page is a list of mosfet distributors, i have spent countless hours emailing these same pictures to distributors, retailers, manufacturers, electrical engineering schools and various other places. gonna have to be alot more specific.

brak: sri: compaq wont do jack! i called them 3 times and even tried once to socially engineer the phone number for any of the system designers offices. guess what, they say the way to fix it is to buy another mobo LOL


salim: i will do a part search for that and see if i can get a match.
im curious as to what exactly you mean by "You have to Sink all possible charge "locked" other related CKT" - i dont know what a CKT is.


RPDC: i will call abra, and thanks for the soldering tips!

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LVL 12

Expert Comment

by:public
ID: 8122617
Just call siliconix, tell them you need a couple of samples of the little foot Si9936 in soic8, and they will send you the parts. Installation is easy if you have rudimentary skills.
You should check at least with an ohmmeter that there is no additional damage to the pcb which would burn the new part.
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LVL 1

Expert Comment

by:brakmat
ID: 8122650
That is what I am talking about...I do warrenty repair for Compaq

I might have a spare laying around...

If you don't want any help why did you even post...
Everytime someone ask you a question you act like it isn't going to help.

Some people have connections at the companies!
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LVL 8

Author Comment

by:ViRoy
ID: 8122724
well i just got off the phone with abra, they are unwilling to let me email a picture of the part to them and wont do anything without a part #. i asked if maybe Si9936as or W206 or 905M, they say nothing.

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LVL 1

Expert Comment

by:brakmat
ID: 8122772
you said earlier that you are the local computer shop...
Start acting like one and just chage the customer for the part instead of trying to find the cheap route out.

If it isn't for a customer and you are trying to sell it...Try selling something that isn't rigged up with Ducktape.

Picture Number 2 looks like someone spilled something on it anyway.
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LVL 1

Expert Comment

by:brakmat
ID: 8122782
you said earlier that you are the local computer shop...
Start acting like one and just chage the customer for the part instead of trying to find the cheap route out.

If it isn't for a customer and you are trying to sell it...Try selling something that isn't rigged up with Ducktape.

Picture Number 2 looks like someone spilled something on it anyway.

Compaq Laptop Repair signing off.
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LVL 8

Author Comment

by:ViRoy
ID: 8122894
lol thats great brak:
its a compaq 1592 laptop - sorry i dont have the serial number for it.
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LVL 8

Author Comment

by:ViRoy
ID: 8123007
spilled on it? not even possible, i am a reputable self serving local computer shop lol
maybe its because that chip melted ya think?
also that black screw is one of those super tiny black screws that is nearly small as eyeglass screws.

please be more patient and less likely to turn your head up and have this attitude like 'well i wasnt gonna help you anyway! hmmph'

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Expert Comment

by:RPDC
ID: 8124984
Ask to talk to the educational sales rep.  That is who I deal with.  Give them the 9936 number.  That is the way they have it listed in their catologue.
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LVL 8

Author Comment

by:ViRoy
ID: 8125191
RPDC: OK! i will call them back in the morning.
sounds like you know for sure what this part is and that they do have it?
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LVL 8

Author Comment

by:ViRoy
ID: 8125229
public: sorry i missed your comment earlier, i will also check into siliconix, i should be able to find their number.
ill get back to you tomorrow on what i find, and as far as the "PCB"... what is that and could you see it on the picture?



--------------------------------------------------------------------------
also, a little bit of info that i forgot to put in the original ticket. the laptop works perfectly fine without the HD, it posts and boots fine.
public: would the PCB affect regular operations? or is it possible that it could still burn a new chip even though it boots ok?
--------------------------------------------------------------------------
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LVL 12

Expert Comment

by:public
ID: 8126259
Frankly the search took less than a minute, since the siliconix logo is still visible.
When you take the old part off, some pads may lift off the board, because the adhesive may have burned. Some blue wire crafting may be needed to install the new chip.
Compared to Alexus power supply designs this is easy, since when he declared parts to be defective all that remained were a few lead frame stubs.
PCB is a printed circuit board in electric contents, not he toxic oily chemical.
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LVL 12

Expert Comment

by:public
ID: 8126267
Maybe the part just puts the HD into sleep mode by turning the power off.
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LVL 8

Author Comment

by:ViRoy
ID: 8132069
doh man i went out to the bar last night and ended up sleeping through my alarm :(
so abra is now closed and ill have to call tomorrow
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LVL 8

Author Comment

by:ViRoy
ID: 8132498
public: i was able to locate the part i think your referring to
http://www.vishay.com/docs/70128/70128.pdf

i wish i could see a picture of it, i noticed that the vishay logo is a triangle... thats pretty close to the seperated triangle on my picture, also might explain why i couldnt find the company by browsing logo's

i am going to try and get some samples sent out, lots of trouble finding a phone number for contact... ill try to find a request form
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LVL 8

Author Comment

by:ViRoy
ID: 8133105
public:
ok, i was able to find a distributer right here in my town!
i am going to call them tomorrow and see if i can swing by and pick one of these up... i hope to god it matches all the power requirements, i am hoping that this part will be identical in every way.
let ya know tomorrow what turns out.

RPDC:
if public is right i will still reward you for your effort.
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LVL 12

Expert Comment

by:public
ID: 8135283
Siliconix logo is a white S with an i in the middle.
Vishay is just a holding passives company.
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Author Comment

by:ViRoy
ID: 8140348
hmm, i wonder who the seperated traingle logo is for.

i stopped by the local office, they turned out to only be a sales office for existing accounts... they referred me to newarkinone.com - i was able to find the part, came to $1.99 + $5/sh .. should arrive by monday
if this is the correct part i will award the full 1500pts + a lil' sumthin for RPDC.
wow this is going to use almost half my available points ;)
oh well, thats what their there for... wish me luck
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LVL 8

Author Comment

by:ViRoy
ID: 8156100
hehe well i just got a shipping confirmation...
so maybe 2 days from today ill recieve it
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LVL 8

Author Comment

by:ViRoy
ID: 8170968

The new part arrived today, good packaging for such a small chip!

Im worried though because the markings on the top are alot different.
have a look:
http://personalpages.tds.net/~csajba/NewChip1.jpg
http://personalpages.tds.net/~csajba/NewChip2.jpg
http://personalpages.tds.net/~csajba/Compare1.JPG
http://personalpages.tds.net/~csajba/Compare2.JPG

For some reason i dont think this is the right part...
Whadya think
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LVL 12

Expert Comment

by:public
ID: 8172914
Looks the same, one is 9936A the other is 9936B. Probably it has improved Rds ON, or some other value. The other markings relate to date code, fab location etc ...
The only concern is that something else was also damaged when the part burned up.
The package is actually archaic, compared to the micro bga with a heat sink used by some high current mosfets.
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LVL 8

Author Comment

by:ViRoy
ID: 8176584
ohhh ok
i didnt know that.
so the 9936 is the only thing that matters?
i was thinking the AP and BO had something to do with the circuit values or pinouts something.

well im gonna see if i can have a jewler to do the soldering for me, i dont feel confident enough with the soldering equipment i have...
i figure if a jewler can fix a small silver chain they can do this, i dont even care if they have to use gold as long as its done right.
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LVL 8

Author Comment

by:ViRoy
ID: 8176598
heres a better perspective on its size:
http://personalpages.tds.net/~csajba/Perspective.JPG

as you can see the pins are a little over 1 thread apart next to the screw!
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LVL 8

Author Comment

by:ViRoy
ID: 8176692
also, public:
can you suggest anything to look at that might have also burned with that chip?

the thing that caused this was a HD being put in this rediculious cartridge with a riser on it... i managed to put in the new HD upside-down and when i powered it on, smoke came right out off the board...
the smoke came directly off that spot but i can understand how something else might have burned with it and not smelled at all.

im hoping at worse, the riser from the HD in the cartridge got burned with it. i didnt let it cook too long but as you can see the breach in the old chip denotes real high temp.

unless i see something obvious im just gonna try it.
i do have a multimeter if you have any suggestions.
the laptop has depreciated about $1000 since the chip first burned :(
but its still a fantastic laptop!
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LVL 12

Expert Comment

by:public
ID: 8179336
Damaged parts may not have visible damage. A cost effective solution is to just try the new part. Soic 8 is considered to be easy rework even with primitive tools. A jeweler may not understand electronic rework. Parts can be damaged by excessive heat.
You may try to cut the leads with small dykes, remove the plastic body, then unsolder the remaining stubs one at a time. Clean up the pads a bit, apply some flux, and place the new part on the pads. Then solder the leads one at a time.
0
 
LVL 12

Accepted Solution

by:
public earned 2000 total points
ID: 8324286
any luck?
0
 
LVL 8

Author Comment

by:ViRoy
ID: 8329392
well i have some bad news, the new chip did not work at all, i cannot get any power to the HDD.
sorry it took so long but i decided to order "ChipQuik", a special low temp SMD removal kit so i didnt damage the pads.

i am going to try and find out what leads have +/- so i can test with a multimeter if power is atleast getting to it, or if the problem is somewhere else.
in the meantime i have already ordered a pretty cool HDD conversion kit right off ebay... with this kit i can use any laptop or AT/ATX style HDD, you put the drive in this caddy and it has a PCMCIA card out... im praying i can boot directly from it, otherwise i should be able to use a customized boot disk to boot to it.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3708&item=3413140275

i found out today that the bios config was stored on a "special partition" hidden on the OEM HDD... i dont know if it will regenerate this when i assign a partition as active or not, but i sure hope so cause i cannot get into the BIOS config.

in the meantime i think this closes the issue in which the question was origionally asked... since i was not able to get it working at all but did get very good help with finding a part, i will reward public the 500 for this question.
0
 
LVL 12

Expert Comment

by:public
ID: 8345544
Check that pin 1 is in the correct location.
When the fet is off, you should see 5V from the drain to the source terminals, and 0V on the gate. When turned on, you should have +5V from the gate to the source, and 0V from the drain to source terminals.
Try to borrow another hdd in case the old one was damaged.

0
 
LVL 8

Author Comment

by:ViRoy
ID: 8370266
i just noticed that the cd-rom does not have power either.
hmmm
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