Hi
I bought a dead spares/repairs laptop to use the screen as a replacement on another same model laptop which I've swapped over already.
I was then intrigued if I can get the spares/repairs motherboard up and running again as I could then use the motherboard to upgrade to another laptop we have.
The laptop was sold as no power / dead and has met it's spares purpose, so this is purely for fun and learning.
I've followed the no power troubleshooting guide with no luck so far. Schematic PDF attached. I've been using pages 31 and 33 mostly.
However, I think the readings may have changed so I could have made things worse.
Model - Compal LA-H091P (Lenovo C340 Ryzen 5)
Adaptor voltage 20.1v at board connector when disconnected from board = 20.1v
When the connector is plugged in to the board the pin out from the connector is 0.4v to 1.1v.
That is the same on pin 1 of PQ740 and PQ712.
However, i'm sure they were previously 20.1v so suspect something has changed whilst I've been playing. I've only used the power adaptor and haven't injected voltage anywhere.
Resistance from ground to the following initial approx readings. The resistance value doesn't stabilise
voltage in = 16K ohms
PQ740 pin 1 = 18K ohms
PQ712 pin 1 = 20K ohms
PQ712 pin 5 = 2 to 4K ohms
Nothing obvious on a visual check of the board. However, UT2 soldering looked suspect. Photo is the before and I've re-flowed it to eliminate it.
Would really appreciate any feedback that may help. I'm an amateur with some experience of electronics, so please be gentle
. Thanks in advance.
[MOD EDIT] Link to Schematic - https://www.badcaps.net/forum/showthread.php?t=105268
.
I bought a dead spares/repairs laptop to use the screen as a replacement on another same model laptop which I've swapped over already.
I was then intrigued if I can get the spares/repairs motherboard up and running again as I could then use the motherboard to upgrade to another laptop we have.
The laptop was sold as no power / dead and has met it's spares purpose, so this is purely for fun and learning.
I've followed the no power troubleshooting guide with no luck so far. Schematic PDF attached. I've been using pages 31 and 33 mostly.
However, I think the readings may have changed so I could have made things worse.
Model - Compal LA-H091P (Lenovo C340 Ryzen 5)
Adaptor voltage 20.1v at board connector when disconnected from board = 20.1v
When the connector is plugged in to the board the pin out from the connector is 0.4v to 1.1v.
That is the same on pin 1 of PQ740 and PQ712.
However, i'm sure they were previously 20.1v so suspect something has changed whilst I've been playing. I've only used the power adaptor and haven't injected voltage anywhere.
Resistance from ground to the following initial approx readings. The resistance value doesn't stabilise
voltage in = 16K ohms
PQ740 pin 1 = 18K ohms
PQ712 pin 1 = 20K ohms
PQ712 pin 5 = 2 to 4K ohms
Nothing obvious on a visual check of the board. However, UT2 soldering looked suspect. Photo is the before and I've re-flowed it to eliminate it.
Would really appreciate any feedback that may help. I'm an amateur with some experience of electronics, so please be gentle
. Thanks in advance.[MOD EDIT] Link to Schematic - https://www.badcaps.net/forum/showthread.php?t=105268
.
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