Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Posted to sci.electronics.repair,sci.electronics.components,comp.sys.laptops,alt.comp.hardware.pc-homebuilt
gk
 
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Default What is this laptop motherboard component?

This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR

Picture he
http://img219.imageshack.us/img219/3850/2042a3ku.jpg

Picture cleaned up:
http://img219.imageshack.us/img219/7...2aclean7cz.jpg

Any ideas on where to find a replacement for the component?

Thanks,
gk

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Tony Marsillo
 
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Default What is this laptop motherboard component?

GK,
You can get the data sheet here.

http://www.datasheetcatalog.com/data...TPS2042A.shtml

--
Tony Marsillo
Nutmeg Repair
-----------------------------------------------------------------
"gk" wrote in message
ups.com...
This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR

Picture he
http://img219.imageshack.us/img219/3850/2042a3ku.jpg

Picture cleaned up:
http://img219.imageshack.us/img219/7...2aclean7cz.jpg

Any ideas on where to find a replacement for the component?

Thanks,
gk



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gk
 
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Default What is this laptop motherboard component?

Thanks Tony,

So the part number I should be looking for is "TPS2042A"? And is it
fairly straight forward to solder? I'm by no means an expert. There's
probably other undiscovered damage to the motherboard that I might have
to worry about too...

Thanks again,
gk

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Robert Mozeleski
 
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Default What is this laptop motherboard component?

http://www.findchips.com/
Lists that but it's 2042ad Mouser lists as Texas Instruments and it's a 8 pin so most likely that. Pin 2 is the
input. Be sure to check for other bad components before firing this back up.
"gk" wrote in message ups.com...
This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR

Picture he
http://img219.imageshack.us/img219/3850/2042a3ku.jpg

Picture cleaned up:
http://img219.imageshack.us/img219/7...2aclean7cz.jpg

Any ideas on where to find a replacement for the component?

Thanks,
gk



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Dave Platt
 
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Default What is this laptop motherboard component?

In article . com,
gk wrote:

This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR


Texas Instruments logo. A wildcard search (*2042a*) at
www.datasheetarchive.com turns up the TI TPS2042A, described as
"0.7A, 2.7-5.5V Dual (1In/2Out) Hi-Side MOSFET, Fault Report, Act-Low
Enable." The data sheet for that part, downloaded via the link
provided, describes it as a "current-limited power distribution
switch" and shows that it does come in an 8-pin package which
resembles the one in your picture. So, I sorta figure that's what you
have there. Must have made a nice BANG when the leg came off :-(

This is apparently an obsolete part - none of the usual distributors
such as DigiKey or Mouser have any in stock, and (apparently) neither
does TI.

TI lists it as having been superceded by an "exact replacement", the
TPS2042B. Digi-Key has the TPS2042BDR in stock for $1.68 each.

That's likely your best bet, I think.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!


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Default What is this laptop motherboard component?

Followups set to sci.electronics.repair.

In sci.electronics.components gk wrote:
So the part number I should be looking for is "TPS2042A"?


I _think_ that is right. If so, TI's page for it at
http://focus.ti.com/docs/prod/folder.../tps2042a.html
says it has been replaced by the TPS2042B. That page says it is
basically a power switch that can handle up to 0.5 A, which is a
relatively large current for inside a laptop. The fried pin looks like
the the input voltage to the chip, and the one immediately to its left
is ground. That looks like a good set-up for a short from the spilled
water.

Digi-Key sells the TPS2042BDR for about $2 each.
http://www.digikey.com/scripts/dksea...=70309&Site=US
For orders below about $25 I think there is an additional handling
charge.

And is it fairly straight forward to solder?


I haven't had much experience soldering surface-mount components. You
need a soldering iron with a fine pointed tip, not big and stubby, and
having some small-diameter solder also helps. If you've got an old junk
network card or hard drive or something kicking around, you might
practice unsoldering and resoldering components on that before attacking
the laptop. http://www.repairfaq.org/REPAIR/F_ts...tml#TSHOOT_029
has good information on soldering and desoldering.

Matt Roberds

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Stuart
 
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Default What is this laptop motherboard component?

It's a Texas Inst. TPS2042A MOSFET fault report, act-low enable. DCFR=Dual
Cmos Fault Report. Datasheet at www.datasheetcatalog.com.

"gk" wrote in message
ups.com...
This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR

Picture he
http://img219.imageshack.us/img219/3850/2042a3ku.jpg

Picture cleaned up:
http://img219.imageshack.us/img219/7...2aclean7cz.jpg

Any ideas on where to find a replacement for the component?

Thanks,
gk



  #8   Report Post  
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James Sweet
 
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Default What is this laptop motherboard component?



I haven't had much experience soldering surface-mount components. You
need a soldering iron with a fine pointed tip, not big and stubby, and
having some small-diameter solder also helps. If you've got an old junk
network card or hard drive or something kicking around, you might
practice unsoldering and resoldering components on that before attacking
the laptop. http://www.repairfaq.org/REPAIR/F_ts...tml#TSHOOT_029
has good information on soldering and desoldering.



Actually I find a big stubby tip works well since I can load it up with
solder. The trick is to tack solder a pin in one corner, or glue the
chip down, then apply a little pool of liquid rosin flux over the pins
and drag a blob of hot solder on the tip of the iron across the leads
slowly, the effect will be much like the original wave soldering, might
want to practice on some junk first though. If you make a solder bridge,
some desoldering wick can clean it up, apply more flux and try again.
When finished, wash off all the flux.
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The Electric Fan Club
 
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Default What is this laptop motherboard component?


wrote in message
news:_d8jf.25237$0h5.12659@dukeread10...

I haven't had much experience soldering surface-mount components. You
need a soldering iron with a fine pointed tip, not big and stubby, and
having some small-diameter solder also helps. If you've got an old junk
network card or hard drive or something kicking around, you might
practice unsoldering and resoldering components on that before attacking
the laptop. http://www.repairfaq.org/REPAIR/F_ts...tml#TSHOOT_029
has good information on soldering and desoldering.


The correct method of removing the old chip is to get a pair of fine
anti-shock diagonal cutters and cut the remaining legs off the chip at the
package. You can then carefully unsolder the cut off legs from the
motherboard, one at a time. Position the new chip with a bit of double
sided sticky tape (or suitable substitute) and then carefully solder the 8
legs.

Attempting to unsolder all the remaining legs in one go (unless you have the
correct tools) is asking to destroy the motherboard.


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Conor
 
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Default What is this laptop motherboard component?

In article .com, gk
says...
Thanks Tony,

So the part number I should be looking for is "TPS2042A"? And is it
fairly straight forward to solder?


Not in that state. You're going to have to do some major track
rebuilding. Not only that, if it's a 3 layer or more board, it might
not work as it could've eaten through another layer and you've no hope
in hell of tracing that.

Even if you do get it soldered, to do that much damage needs a hell of
alot of current and there's probably damage to other components too.


--
Conor

"You're not married, you haven't got a girlfriend and you've never seen
Star Trek? Good Lord!" - Patrick Stewart, Extras.


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Conor
 
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Default What is this laptop motherboard component?

In article , Dave Platt says...
In article . com,
gk wrote:

This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR


Texas Instruments logo. A wildcard search (*2042a*) at
www.datasheetarchive.com turns up the TI TPS2042A, described as
"0.7A, 2.7-5.5V Dual (1In/2Out) Hi-Side MOSFET,


Highly likely something else has been killed too then if it's a MOSFET
and there's that much damage.


--
Conor

"You're not married, you haven't got a girlfriend and you've never seen
Star Trek? Good Lord!" - Patrick Stewart, Extras.
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Dave D
 
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Default What is this laptop motherboard component?


"gk" wrote in message
ups.com...
This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR

Picture he
http://img219.imageshack.us/img219/3850/2042a3ku.jpg

Picture cleaned up:
http://img219.imageshack.us/img219/7...2aclean7cz.jpg

Any ideas on where to find a replacement for the component?

Thanks,
gk


The pad is completely missing, leaving a thru-hole visible where the pad
used to be. You'll have to trace that thru hole and see which component it
leads to so you can link it with wire.

IMO, this is not a practical repair for anyone but the most experienced
engineer. It's almost certain that when the component shorted it took out
other semiconductors, possibly the regulator IC, chipset IC, maybe even the
CPU.

Your best bet might be finding the same model with a cracked LCD on eBay,
and swapping the LCDs over. However, even the same model laptops have been
known to use different LCDs.

Dave


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Mark D. Zacharias
 
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Default What is this laptop motherboard component?


"gk" wrote in message
ups.com...
This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR

Picture he
http://img219.imageshack.us/img219/3850/2042a3ku.jpg

Picture cleaned up:
http://img219.imageshack.us/img219/7...2aclean7cz.jpg

Any ideas on where to find a replacement for the component?

Thanks,
gk


I would try just cleaning away the corrosion first. You might get lucky.

Mark Z.


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Dave D
 
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Default What is this laptop motherboard component?


"Mark D. Zacharias" wrote in message
et...



I would try just cleaning away the corrosion first. You might get lucky.

Mark Z.


You might want to take a closer look at the second picture ;-)

Dave


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Woody
 
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Default What is this laptop motherboard component?

http://focus.ti.com/lit/ds/slvs247/slvs247.pdf
"gk" wrote in message
ups.com...
This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR

Picture he
http://img219.imageshack.us/img219/3850/2042a3ku.jpg

Picture cleaned up:
http://img219.imageshack.us/img219/7...2aclean7cz.jpg

Any ideas on where to find a replacement for the component?

Thanks,
gk





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Al
 
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Default What is this laptop motherboard component?

In article ,
"Woody" wrote:

http://focus.ti.com/lit/ds/slvs247/slvs247.pdf
"gk" wrote in message
ups.com...
This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR

Picture he
http://img219.imageshack.us/img219/3850/2042a3ku.jpg

Picture cleaned up:
http://img219.imageshack.us/img219/7...2aclean7cz.jpg

Any ideas on where to find a replacement for the component?

Thanks,
gk




I'm afraid you are cooked! It looks like the pad for the part is gone
also. If there was an electrical short afterwards which fused the
metallization, it may have caused damage to the metallization runs
underneath. At any rate, it may be impossible to make connection to that
one pin unless you know exactly where it goes and can put in a jumper.

Al
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Franc Zabkar
 
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Default What is this laptop motherboard component?

On Wed, 30 Nov 2005 10:31:09 -0000, "Dave D" put
finger to keyboard and composed:


"gk" wrote in message
oups.com...
This is my first time posting, so I apologize ahead of time for any
breach in netiquette.

Can anyone please help me find out what this component is? It shorted
out (water spill) on a Dell Inspiron 5100 laptop motherboard. It is an
8-pin package and the markings a

2042A
36T
DCFR

Picture he
http://img219.imageshack.us/img219/3850/2042a3ku.jpg

Picture cleaned up:
http://img219.imageshack.us/img219/7...2aclean7cz.jpg

Any ideas on where to find a replacement for the component?

Thanks,
gk


The pad is completely missing, leaving a thru-hole visible where the pad
used to be. You'll have to trace that thru hole and see which component it
leads to so you can link it with wire.

IMO, this is not a practical repair for anyone but the most experienced
engineer. It's almost certain that when the component shorted it took out
other semiconductors, possibly the regulator IC, chipset IC, maybe even the
CPU.


I'd remove the IC and check the voltage on the input pad (after you've
repaired it). I'd also check for shorts on the output pins (6 & 7). It
may be that one of the IC's internal MOSFETs failed catastrophically.

Your best bet might be finding the same model with a cracked LCD on eBay,
and swapping the LCDs over. However, even the same model laptops have been
known to use different LCDs.

Dave


-- Franc Zabkar

Please remove one 'i' from my address when replying by email.
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