Here's a head scratcher!

For decades, I resorted to learner remotes that eventually got damaged thru heavy use. This old Hitachi receiver is in our bedroom, and I'd like to use my Samsung tablet to power it up and use it.

Problem: it's a rare product whose codes can't be found online.

It was sold new with a DVD player that does work with standard Hitachi DVD codes.

The part number for the remote is: HL01512 (RB-HTAR150)

Does anyone recognize this product, or do you have tips on how to attain the hex codes for it?

It's comparatively small to the receivers of the era, 4x8x10 (inches).

Any help with this would be appreciated.