Service for Tube Int Amp

Looking near Chicago for service store that works on tube Int Amp. More specifically a Jolida 502B that the right channel is out.
Have you done any basic troubleshooting? Maybe its something simple like a blown fuse.
I forgot to add that Music Direct is in Chicago and they're a big Jolida dealer. I don't know if they can fix it on site, but its worth a try. Some of the bigger stores I deal with have service departments.
Look up some electronic places that fix stuff like this. Look in phone book. I know of a place on Belmont, that fixes tube stuff.
Give Deltronics a call. They have a few locations in the Chicago area.