Thanks for the tips! Lifting a leg of the coil showed that the short was on the side of the PCH. When I injected voltage, the PCH got warm, and using some alcohol, I could see that it got warm the fastest at one spot along an edge, so I guess that definitely shows the PCH is shorted. Too bad, but at least now I know that I don't need to search for any other issues.

Hmm, after looking around a bit more, I have a suspicion that the PCH is shorted, in which case I unfortunately won't be able to fix anything. I guess I need to inject voltage to see if it heats up. According to some videos I saw, if I put isopropyl alcohol on the PCH while injecting voltage, and it evaporates more quickly in one spot, that probably means there's a short. Should I start with a voltage of 0.8V or so to be on the safe side, or can I just go straight to 1.8V?

Hi,

I have an AsRock B560 Pro4 (boardview: [URL]https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-desktop-motherboards-graphics-cards-and-pc-peripherals/bios-schematic-requests/3231141-asrock-b560-pro4-schematic[/URL]) that's completely dead (it doesn't even turn on the power supply when the power button is pressed or the power button pins are shorted). I do get about 3.4V on the power button pin, but 1.8VSB isn't there. The resistance to ground on the inductor PL53 is only about 0.1-0.4 Ohms. Am I correct in assuming that there...

I must correct myself. I don't know what I messed up while measuring before, but now PU2 [I]does[/I] actually have 3.3V on its output. However, PQ8 only has 3.3V on its drain (see page 50 of the schematics). If I understand it correctly, this MOSFET is switched on when 3.3V_ALW is present, which is powered by PU100 (page 51). For PU100 to work, PWR_SRC needs to be present, and that brings us back to the ISL9538H (PU901) and its surrounding circuit. Does that make sense, or am I missing something?I must correct myself. I don't know what I messed up while measuring before, but now PU2 [I]does[/I]

Thanks for the suggestion. VIN has 19.5V, all other pins have 0V. The VOUT pin has about 100K resistance to ground, so there's no short there. I'm guessing that voltage regulator is dead then? I couldn't find a perfectly matching replacement chip in my collection of dead motherboards. The closest thing I found was a G920AT24U, which is the right voltage but doesn't seem to have the same current handling capacity as the RT9058-33GX (see attached datasheets), so it's probably best if I just order the correct chip....

Hi,

I have a Dell Latitude 5590 with motherboard LA-F411P Rev 1.0 that has liquid damage and doesn't turn on anymore when only the charger is plugged in. However, it does turn on when powering it from a battery. I couldn't find schematics for this exact board, but LA-F401P seems to be similar (that post says LA-F411P, but the attached schematics are actually for LA-F401P): [URL]https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/schematic-requests-only/98588-ddm80-la-f411p-schematic-or-boardview-needed?p=3262678#post3262678[/URL]...

Hi, I don't have any background in electronics, but I like repairing things, and the resources on Badcaps have helped me a lot already.