'94 AM/FM Cass issue

Just removed after-market CD exchanger (trunk mount) from my '93 Euro and installed in my '94 Euro. Had it working for a few minutes. Removed temporary connectors to solder in place. Now can't get anything.

To check out system wires, installed each stereo in both cars. Both stereos work in the '93 and neither will work in '94.

Is there some type of "theft-deterrent" system that could have me locked out of the new stereo configuration?:

Did you check the simple things like fuses and grounds?

Fuses, yes.
I get hiss from the stereo unit, but no LED or functionality.
If I had a bad ground, I would expect other intermittent electrical issues?

There are two power wires to the radio, one is ignition controlled (usually Yellow) for the radio functions when the key is on. The second (usually Orange) has power all the time and is protected by a different fuse. It is for the clock, radio pre-set memory, etc... Finally, the radio grounds through the antenna cable as well as the wiring harness, so double check your antenna cable to make sure it isn't cut.