can't find remote codes for a rca surround/dvd player or audiovox tv/dvd player in order to program a remote?

I have an ATLAS OCAP-5 universal electronics remote control, I have an RCA RTD3131 surround/dvd combo which there are no codes listed for, so I tried the rca dvd codes to no avail. I also have an audiovox tv/dvd combo in which there are 3 codes in the guide book that also do not work. Lastly, I tried the "searching for your code" as instructed in the remote's manual on both combo devices, which also didn't work. I followed directions in the guide for setting up "programming device control" and "setting up a combo unit". Any help would be greatly appreciated. I am very frustrated with this. thanks.