Hi guys
I have this Toshiba Lifebook A514
When I got it the battery was flat, orange Battery LED on. When you press the power button, with PSU attached, the blue LED by the button (and the one at the front of the laptop) come on, but no fans no signs of life... Nada.
I left it overnight on the charger and the battery did charge - no more orange light and the laptop will now power on without the PSU - but still no signs of life
If you hold the power button in, it will not power down again, you have to switch off power to the PSU
If you do that it takes 10-15 secs for the power LED to go out. ie. It's drawing very little power from the PSU
I removed the motherboard and found I have no power on four of the buck regulators - see pic. I also checked the resistance on each coil that had no output voltage. Starting from the to of the pic (nearest the fan) I have
96.9R (possibly Vcore)?
65.6R (possibly GPU)?
253R (changes to 176 with DIMM fitted so it must be Vram)
Very high resistance on the small buck coil
The CMOS battery is good. I removed it for 20 secs to hopefully clear CMOS
Before I start looking for datasheets to check Vin and EN pins on the inactive buck controllers, does anyone with experience of laptops have any other suggestions?
Is there a schematic/boardview for this laptop? A forum search for Lifebook A514 returns no results. Yes I know there is a schematic request section but I hoped to keep it all on one thread rather than two.
I have this Toshiba Lifebook A514
When I got it the battery was flat, orange Battery LED on. When you press the power button, with PSU attached, the blue LED by the button (and the one at the front of the laptop) come on, but no fans no signs of life... Nada.
I left it overnight on the charger and the battery did charge - no more orange light and the laptop will now power on without the PSU - but still no signs of life
If you hold the power button in, it will not power down again, you have to switch off power to the PSU
If you do that it takes 10-15 secs for the power LED to go out. ie. It's drawing very little power from the PSU
I removed the motherboard and found I have no power on four of the buck regulators - see pic. I also checked the resistance on each coil that had no output voltage. Starting from the to of the pic (nearest the fan) I have
96.9R (possibly Vcore)?
65.6R (possibly GPU)?
253R (changes to 176 with DIMM fitted so it must be Vram)
Very high resistance on the small buck coil
The CMOS battery is good. I removed it for 20 secs to hopefully clear CMOS
Before I start looking for datasheets to check Vin and EN pins on the inactive buck controllers, does anyone with experience of laptops have any other suggestions?
Is there a schematic/boardview for this laptop? A forum search for Lifebook A514 returns no results. Yes I know there is a schematic request section but I hoped to keep it all on one thread rather than two.
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