Power and Keyboard Problems After Battery Replacement

Summary: Keyboard and trackpad do not work after battery replacement, and laptop can only be on when power cord is in. In more detail:

Everything on my laptop worked fine except the (OEM) battery. I replaced the OEM battery with a Cameron Sino battery. The laptop powered on when plugged. The power button worked. I got the usual login screen but had a battery warning icon on the top right. The trackpad and keyboard did not work. I reopened the laptop and re-secured the IPD cable. Then I powered on again, and the trackpad and keyboard did work. I logged in and got my usual desktop. However, now the trackpad and keyboard did not work. The battery icon on the top right indicated 0% charge. I powered down and let the laptop sit with the charger plugged in for a few hours. Then I powered on and the trackpad and keyboard did not work again. I adjusted the IPD cable more times but each time the trackpad and keyboard did not work on login. Furthermore, the laptop immediately shut down if the power cord was removed. This was despite having left the cord in for hours.

Here is some further information that may be relevant. I replaced the OEM USB-C I/O cable (attached to power cord) with a third-party cable. I am missing two case screws, including one of the longest screws that attaches near either the power button or power cord socket. The case is slightly misaligned, possibly because the battery was misaligned when I installed it. I did not use anti-ESD equipment while I was disassembling and reassembling the laptop. And I disassembled and reassembled multiple times. A tiny ball bearing fell out of the laptop while I was assembling, and I do not know where it was from. I had to peel away some of the small fuzzy-backed tape while inside the laptop. Some dirt may have gotten inside parts.

These are my current hypotheses about what is wrong: It may be the battery is defective. It may be that I caused permanent electrical damage to some part. It may be something is shorting inside the laptop because parts are not completely secure, but there is not permanent damage. It may be that one or more cables are not completely secure.

If you think the problem is the cables not being completely secure, please give tips on how to make them connect better, especially the IPD cable. If you think I bricked my laptop, please help me determine how to recover the contents of the hard drive.

Note that I cannot reset the SMC, NVRAM, or PRAM since my keyboard is not working.