Daphne, Try using auto code search feature, found on most universal remotes. Instructions should be in your manual. From one of the forums they suggested this. Place your tv on channel 3.
Point your GE universal remote at the converter box, press and hold the setup button until the red light remains lit, then press and release the DVR/AUX button. The red light will blink once.
Enter 0581 as the code, then press Power and the Converter box will turn on and your channels will pop right up.
Check the attached links,instruction,guides, read through them, as they have fixes to program remote. Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."
RC Controlling the Magnavox TB100MW9 Digital Analog Converter Page 2 of 2
Remote Code Finder