I'm assuming you're trying the type of universal remotes where you punch in a code and it automatically maps the universal remote's keys. That you are not learning the commands from your existing Sony remote. Take a look at

[Link: hifi-remote.com]

This has codes for Radio Shack and One-For-All remotes. It appears that the 158, 010 and 159 codes are used for Sony amps and receivers. Will these work with you mini component system? Don't know. You'll have to give it a try.

Please post the universal remotes you've tried. That might help us help you.

Your best solution maybe a learning remote. Most, but not all, universal remotes have this capability. There are hundreds of choice for this. Ranging for less than $20 to $$$$.

There are a few remote signals (IR - infrared) that are difficult to learn. Things like B&O, some Kenwoods. I know there are others but these pop to mind. I don't think your Sony will be one. Can you control your Sony from another room? If so, you have a RF (radio frequency) remote control system. In most case, these can't be learned.