WOW! I used to have both a Citation 16s (without the v pattern leds on the front) and a pair of DQ10's. A dynamite combo! Then one fateful day something happened. I think it was from an electrical storm outside although I can't be sure because nothing else was affected but I heard a loud pop in the middle of a track and then smoke came out of one of the DQ10's and the Citation 16s... BOO. Anyway, I usually bring problems like the one you're speaking of to an old school tech near my place. He specializes in analog electronics and has been servicing high end gear for years. If you find someone like this they're priceless. You probably could figure out the cable on your own if you had to but sometimes it's worth paying someone with lots of hands on experience. Good luck.

ps not sure if you're aware but Dahlquist built a successor to the DQ10... the DQ TEN!

http://www.dahlquistcorporation.com/DQ_TEN_cover.htm