Black screen on power up shuts off 1 min later, LEDs work, what’s bad?

L75D-A7283, running Windows 10 Home

I upgraded to an SSD, SATA III, and upgraded the RAM from 6GB to 16GB.

Laptop ran fine with my older power supply I had purchase years ago. Not OEM, but worked for my L305D.

Worked for three weeks before I was running it on battery only one morning, and the battery was getting low, so I plugged in the power supply and poof, the laptop went out like a light switch.

I unplugged it immediately, and took out the battery, to prepare to do static discharge,

I hold the power button in for 30 seconds, and notice that I smell a faint electrical smell, (you know the burning wires smell).

I heard the remaining power discharge, and before plugging it back in, I grabbed my other power supply. I have a universal one with interchangeable adapter plugs so it works with several different mfg devices. (this was 60W so I figured it would be ok)

I tried powering it back on, only plugged in, nothing.

I turned it over to put the battery back in, and held the laptop to my nose, the burnt smell was terribly faint now, but only around the are where the fan is in the corner.

I put the battery in, and the LED came on orange as if it were charging. It powers on, the white light surrounding the power button turns on, I hear the fan, but BARELY. The cap lock light flashed once as I turned it on. I tried pressing the cap lock button a few times to see if it would light up, and it did when depressed like it should. NO display again, black screen only. I hold the power button in, and turn off the laptop.

I tried turning it back on, would not power on, so I unplugged it, took the battery out (again), held the power button for 60 seconds, plugged it back in, (no LEDs), put the battery back in, (no LEDs came on this time), I pushed the power button, and nothing.

I tried to discharge it again, (now thinking I was doing it incorrectly, I grabbed my other laptop L305D, and plugged the old power supply into it, and went to turn it on, and POOF same thing happened, it turned off like a light switch. (I immediately threw that power supply in the trash) Took the battery out of the L305D and held the power button for 60 seconds, then plugged in the universal power supply I had been just using, and put the battery back in, and Boom the L305D started right back up like nothing was wrong. Booted up no problem. (So now I at least knew the power supply was giving enough volts)

Went back to the L75D, tried to turn it on again, powered on, and LED came on, but WHITE this time instead of orange.

Still no display, and I couldn’t really hear the fan, and I held my hand up next to the vent to see if I could feel it pushing air, but hardly at all.

I thought maybe the video is messed up, so I grabbed my HDMI cable, and my Desktop ASUS Monitor and plugged it into a separate power source, and turned it on (it displays the “no signal” message) Tried the laptop again, powers on, I can sort of hear the fan, White LED, the external monitor didn’t receive signal either. I shut it off, unplugged the monitor and cable and tried to power it on again.

Same result, I noticed within 60 seconds, of having the laptop on, it powered itself off. I thought this was strange, I powered it on again and it acted the same, stayed on for about 60 seconds and then powered off.

I took the old HDD that I had previously used and swapped out the SSD for the original HDD. (Which I know still works because I had booted to it via USB SATA Adapter on my HP laptop.) I re-seated the RAM while I was in there.

Tried again to turn it on, same result, it powered on, white LED, now I can hear the HDD spinning, and the fan giving the same low speed it had previously given, but no display still, and within 60 seconds or so, the laptop powers off on it’s own, again.

Now I thought, maybe the RAM is causing the problem, so I put the old RAM back in, and tried again. Same Result.

I thought maybe the CMOS battery was bad, since it seemed like I was getting nothing from the motherboard, so I un plugged the power supply, took the battery out, unplugged the RAM, and HDD and set it aside, then took the CMOS battery out and I had to leave for work, so it sat all day with the battery out.

Came home, put a BRAND NEW CMOS battery in Energizer brand nonetheless, and put the RAM back in, and the HDD and battery, and plugged it in, hopeful it would have reset the BIOS and let me get into BIOS setup at least.

NOPE, same result.

I took the laptop all the way apart this time, to take a good look at the motherboard, and I also wasn’t convinced the fan was actually running properly.

I started searching websites for troubleshooting fixes using my iphone. Watched videos on common problems, and resolutions. Most of them were for what I had already tried, or completely irrelevant.

I had seen a video where someone unplugged the ribbon cable to their auxilliary sound ports (which looked burnt) and then their computer powered up, so I tried unplugging the USB port board, and inspected the area around the power jack and the motherboard where the fan and display cable is. Nothing visibly wrong, and still same result. trying to power it on.

I tried unplugging just the CPU fan, to see if it would post properly. Nope.

I tried re-seating the display cable, to see if it had become loose, or burned or anything.

No difference was found, even the fan was in fact spinning up at power on.

I had trouble in the past with an old HP laptop where the power jack had come unsoldered from the board and I had to resolder it myself. Which was a relatively easy fix. So my next thought was maybe something happened internally to the power jack harness.

I purchased a replacement, and just swapped them out last night. But received the same result yet again. No display, and WHITE LED, and fan and HDD spin, but then device powers off after 60 seconds.

Since I had the device apart again, I took the motherboard completely out and inspected it more carefully.

There was no indication that anything had burned (at least not to the naked eye) since I have no microscope or infrared camera to look at it more carefully.

I searched the internet again, and came across a video where someone had the actual schematic of the motherboard on a screen in front of him. They tested the power supply, and the power jack harness with the digital multimeter. Both showing 19.5V. Then tested various places on the motherboard itself, some showing 19.5V some showing 3-5V.

They deduced there was a short, used and infrared camera to see where it was, and removed it with flux and replaced it with a spare one of the same capacity. Just the small little capacitor.

Well, I’m thinking now, i don’t have flux, I have my soldering iron and solder, but I didn’t visibly see anything burnt. I got out my multimeter and tried to see if I could deduce where on the motherboard the problem was. The power supply, the power jack and the transistors directly behind the plug on the motherboard, all were receiving the 19.5V.

I’m a little unsure of where else to try with the multimeter, (having no schematic of my own anywhere, Thanks Toshiba) But I’m not sure if I missed something else.

I came to IFIXIT and read through the better part of 34 pages of questions and answers from people on here, mostly the same problem I have, and most of them never replied to the thread to indicate if the fix worked, or even if they got their computer fixed some other way.

Most of what I read, I’ve already tried as well. Only trouble is trying to get a good description of what happened to the consumer’s computer is difficult.

I feeling like I am the only person I find that had the adapter, “kill” the computer, and then smelled burning wires very faintly, near the fan.

Can anybody offer up any suggestions? I even read about it being a possible BIOS update problem, and needing to re-flash the BIOS.

I’m not sure if i do, but I have a photo I can add here, of details I got out of the Registry entries when I USB booted to the hard drive about the BIOS details and possibly other important pertinent info that someone with more experience could use to help me out.

Did I miss something somewhere?