Which NVRAM did you install?

I installed (3) 5101 from Pinitech on System 80/b games with no issues.
https://www.pinitech.com/products/5101_nvram.php

You changed the correct part location Z5?
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Sometimes you have to push on it in different places as you turn on the game. If that still failed, try another spot and turn it on again. There was only one small area where I could push on at the time that would allow my Gold Wings to boot.

I do not have any experience with that one in particular from him, thought I had bought some other type for system 11 and WPC.

Do you have an old 5101 RAM you can try?

Any of the solder joints related to the mounting of the daughter board is suspect more than the PROM socket, but it can be that too.

How about posting a picture of the MPU board?

I don't think the game will boot without the reset board plugged in since this is a system 80B. Normally, it is plugged in just to the right of the MPU, which currently is showing missing in the pictures.
2019-10-29 07_17_14-Internet Pinball Machine Database_ Premier 'Hollywood Heat' Images - Internet Ex (resized).png

Have you tested all the pins to adjacent pins on the IC socket to be sure too much solder did not flow thru to the top side shorting out adjacent pins?

Check out that RAM IC socket thoughly first.

I definitely would remove the IC socket that was installed and take a picture of the traces under it and zoom up on pads to be sure they are connected to the traces.