This board is out of an HP laptop. There is no voltage present at pin 8 of the Winbond BIOS chip. A nearby coil is a near dead short to ground. Injected 1v and it drew 2.8a but nothing was warm on the board. Then I upped the voltage to 2.5 and 3.5a were drawn, but still no heat. Is that crazy?
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Re: shorted power rail - drawing 3.5 amps but no heat?
Could the heated part be the CPU that may be with a heatsink? -
Re: shorted power rail - drawing 3.5 amps but no heat?
Great! Maybe better to begin from MB model and the pictures? How you measure the temperature: by finger, lips?Comment
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Re: shorted power rail - drawing 3.5 amps but no heat?
mb from hp, near some coil... What kind of help do you expect with such inputs? Which coil? if no position at the MB silk, then show it on the pictureLast edited by gs84; 03-02-2023, 04:50 PM.Comment
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Re: shorted power rail - drawing 3.5 amps but no heat?
ok, I'll wait.
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Re: shorted power rail - drawing 3.5 amps but no heat?
If you can just mention the coil number, i can tell you which rail it is as i've worked on plenty of this model. Schemaic is not available for LA-D704. Whatever schematic you see labelled as D704 is not an exact schematic. Its a blunder to inject 2.5V on any coil.Comment
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Re: shorted power rail - drawing 3.5 amps but no heat?
Also possibility exists that SIO is shortComment
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Re: shorted power rail - drawing 3.5 amps but no heat?
1V/5A and sometimes even 1V/10A.Comment
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Dear all,
I have taken out the motherboard of a Acer TravelMate P214. There is a short to ground on the main power rail (19V). I don't have the schematics or boardview for this board (DAZ8IMB1AA0 REVA). But I have found 4 MOSFETS close to the main power rail : 2 N-Channel and 2 P-Channel.
I have checked resistance across each of the 4 MOSFETS. I have the following readings:
Both N-Channel Mosfets: nothing odd
P-Channel MOSFET number 1:
source - drain : 117 kOhm
source - gate: 96 Ohm
gate - drain: 117 kOhm
P-Channel MOSFET... -
Dear all,
Laptop is Lenovo Thinkpad L480 (boardview can be found in this badcaps topic). When pressing the power button the LED power light turns on, but nothing else happens.
I removed the motherboard, checked for shorts on the main inductors. I found that there is a short to ground on the +3VALW_P rail (@PL201). I soldered a wire on the PL201 inductor, and I injected up to 1.3V with my power supply. Current drawn is approximately 3.2A.
I used a small thermal camera to locate the shorted component. But nothing on the board heats significantly, except the... -
Hello,
This is my problem:
Laptop: Dell Latitude 5501
Motherboard: EDC51 LA-H181P
I have two power rails shorted to ground, +1.0V_PRIM and +3.3V_ALW_PCH. I removed solder on PJP302, +1.05VALWP (pad1) not shorted but +1.0V_PRIM (pad2) shorted.
I also cleaned PJP38, pad1 not shorted, pad2 (+3.3V_ALW_PCH) shorted to ground.
I measure the resistance of all the coils on the motherboard and they all were not shorted to ground except coil PL301 before I removed the solder on PJP302.
I injected +1.05V - 2A... -
Hey guys,
i've got this laptop from a friend who gave it to me in a dead state.
The laptop wasn't working at all so i've began my search on the 19V power rail.
It was shorted to ground so i injected voltage and the only thing getting hot was my ground clip from my power supply.
I found that the +1.05V Rail for the Chipset was shorted. i removed the coil and it was shorted on the power delivery side.
The pch seems fine bc the rail has over 50 ohms after i removed the coil.
Still nothing was getting hot so i suggested the chip must... -
Hey guys got laptop like above. Came to me with shorted main power rail and battery protecion on ( 0V on output). Got rid of short but nothing. Bench power supply says it takes nothing, but still got all voltages 1,2v,3.3v,5v - all good. Thermal cam showed nothing is starting even for a sec. I believe that since all coils etc are good resistance to ground it's probably one of chips. Can be IO chip or maybe something else? Could somebody help me out with this one - it's blowing my mind lol
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