There is one more thing that you need to check. Please check the breather tape on the cartridge. if it is not removed yet, remove it as it doesn't let the ink come out on the paper, which results in printing blank papers.
I have a few memories with MX700, I used it for a few years around 13 years ago. Restoring the old machine is one of the best feelings. I can imagine how much you have enjoyed doing that.