Chosen Solution
Long story short I replaced a trackpad for one of our employees, and now the laptop won’t stay on. When I go to turn it on, it will turn on for a few seconds with fans running and everything, the screen will flicker for a brief second then will shut off. Here is the list of steps I already tried. I tried reseating all components. I cleaned the fans. I reseated the processor (yes with new TP). I tested with new CMOS. I changed the battery. I tried without a battery while being plugged in. The only thing that I could possibly think it would be is a short on the motherboard. I do not want to buy a kit for testing and fixing this unless I am at least 90% sure that is the issue. Every other site I post on just tells me to troubleshoot the battery and charging port, but honestly I do not think that is what this is. Thank you I fixit. PS I love the kit I just bought :)
This is indeed a tough one. It’s obviously not even executing much or even any of the UEFI. You don’t mention the RAM, but I’m sure you’ve tried swapping that. You say you tested with new CMOS. Did you unsolder the CMOS chip and replace it, or just replace the battery? If the former you might have disturbed soething else. And of course, you connected the CMOS battery the right way round! My best guess is that it might need the motherboard re-flowing. But any attempt to re-flow it without a propper re-flow oven is very much kill or cure, and a cure may not last. Lead-free solder is more brittle and less reliable than leaded and in disturbing the motherboard a older joint on a BGA device has fractured. Lead-free older can also grow whiskers which can cause shorts. You say you’re in an organisation which I presume has a number of these T450’s. The acid test would be to swap the motherboard with another, perhaps one with a different fault, like a cracked screen. Or maybe you could pick up one cheaply on eBay listed as spares or repair, which appeared to have a good motherboard. You say you replaced the trackpad. Are you sure the employee was telling you the whole story? Perhaps he spilled coffee on it and cleaned it up pretty well but nevertheless, the trackpad died. And now the motherboard has gone the same way. Any residue on it?
Since this is the only thing you changed (right?) have you tried disconnecting the new Trackpad? I mean if it worked before what else has changed? I’m assuming you were very careful when you first did the replacement? Troubleshooting Golden Rule - Keep it simple.
