Mark Levinson No.26 Balanced Input Question

My ML26 preamp has PHONO boards which work fine with turntable. I never use balanced input. Yesterday I use a pair XLR cable from CD player to Balanced Input, Input Selector to PHONO/AUX2. no sound come out from speakers. Follow the manual reset DIP switches on the PHONO boards to balanced input gain, No sound come from speakers. Don't know why. Please help. Thanks.