I dug up my old Hitachi world-capable TV. Unfortunately, I can't find the remote for it. So begins the quest to bring it back into use.
Universal remotes have codes that will activate most of the functions, but the TV has 4 colored buttons that are required to configure which system you're tuning. So far none of these universal remotes will send those functions, even the ones that have buttons of those colors. They're apparently for DVR use only.
So, I built an IR receiver circuit on my Arduino and started hitting it with codes that DO work. Isolated the address part of the protocol and built a list of working functions and their codes. Now I built an IR transmitter and started trying the other codes until I found the ones that activate the missing functions.
Now all I need is a learning remote to program them into.
Moral of the story: Never lose your remote. Ever.