My shperex xbox 5.1 doesn't work for the right speakers

You don't say if all speakers work with the setup procedure. THAT is step 1. Then try FM as it doesn't require any cabling. Then move on to more complex sources like external analog, then digital (and make sure to assign the ports).

Assuming that you mean Dolby digital 5.1, confirm that you have a center channel properly connected and perform the following;

Using the remote, enter the menu on the receiver and navigate to the selection labeled "LEVEL." Toggle through the selections until you reach the "CENTER CHANNEL". You will be able to use the remote to increase the volume of that channel in .5dB increments.

I don' know what type of system you have, but try to switch system to "SURROUND" mode, or "DSP" mode.

Sounds interesting.
It may sound silly, but can you check all your speaker cables again and confirm whether they are connected to the right connections. please check all cables as also the severed one and please repair it also.

Now please go to the system-set-up and do an auto setup and set up your speakers. Listen to the test tones and confirm that they are coming out of the correct speaker.

Once these are set, then if still there is mismatch of sounds, then we could further trouble shoot.

I had this problem with my surround. The way I solved mine was by hitting the "sound" button and it showed me a small symbol that looked kinda like speakers and I hit the button a few times untill all of the speakers were lit up. Your button may be different but you can use what I tried as a guideline on how to try and figure yours out.

Sounds like the rear volume is just turned down. Cant be the amp if the front and subs are working

Hey Tad, I have the same problem and perhaps a solution. I just moved to the other SW "pre-out" and it seems to be working..the green light is on . Whatever works i guess.

go to audio set up and configure the system for 5.1 or higher sound output.then only all the speakers ll work

You need to use a digital interface cable between the sound card and the speakers to get all of the 6 channels to work properly.