The usual reason remote buttons don't work is dirt, or deterioration of the
contacts. Opening and thoroughly cleaning the keys and contacts might work.

Two other points...

Have you contacted Akai or Sony? They might still have remotes. About six
months ago I found a company -- sorry, I can't remember the name -- that
buys up excess parts inventory -- and bought a rare remote control for a
rare JVC product. * Have you Googled the model number of the remote?

I'm not surprised the universal remotes didn't work. Many remotes have
incorrect or missing codes for necessary functions. For example, the 0 key
for replacement Toshiba remotes doesn't work! And good luck finding a
Toshiba replacement that includes such features as PIP, or even access to
the picture settings.

* It should be noted that most manufacturers blatantly ignore the Federal
laws that require them to stock replacement parts.