Chosen Solution
When I plug in the CA adapter, and press the power button, nothing happens. There are no LED lights, the fan does not turn on, no noises from the hard drive, nothing. The AC adapter appears to be good, it gets the required voltage to the motherboard. Voltage checks on the motherboard show CPU 19.5V, power button 3.34. I have tried removing hdd, ram, resetting the bios and checking the CMOS, and each time trying to power the laptop up, still no joy. I do not have the schematic diagram. How do I proceed to fix this problem?
This trick got me two i7-4600U IPS FHD Touch E7440’s for $98/unit* - one sadly needs a screen (bad backlight) and neither sold with a battery, SSD+cable/caddy or RAM (although I did rummage up some 4GB DDR3L modules), so I may not be able to economically repair the bad unit :(. That said, the one with a good LCD is ready as soon as I buy a battery and a HD caddy+cable, and possibly put a matched RAM set in. I’m recycling an SSD from another machine. *Covid market - even desperate parents didn’t want to touch that gamble for their kids for Zoom school. It’s because the possibility of a bad board is very, very real. Pull the CMOS battery for 1-2 minutes and try to boot without it. If it boots, the CMOS RAM was corrupted. If it doesn’t, confirmed bad motherboard. It’s not like this isn’t known, so I don’t mind revealing it. The issue is some Dell laptops are sensitive to CMOS corruption moreso then others. The E7440 is a 2-in-1 special: it hates booting with CMOS corruption (which isn’t entirely uncommon) and it’s somewhat voltage sensitive. I suspect your Vostro is in that same group.
