No sound from phono preamp


I just set up a VPI Super Scoutmaster turntable with JMW-9 arm connected with Nordost Heimdall cables to the phono stage. It works great with the phono stage in my preamp, but when I connect the arm to my stand alone phono pre (RCM), there is only hum but no sound. The RCM works like a charm with my other turntable. Any suggestions what that could be and how to address it? Thanks!
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Does your stand alone have a mute switch?Do you have the cables to the correct RCA jacks? (Like accidentally having the in cable on the out RCA jack? and vise versa? Is the phono box out to an active RCA set of jacks on the preamp? Check it again..
Does your stand alone phono have internal jumpers? Have you checked them?When I am stumped. I take all the cabling apart, and start over. Usually I find the mistake I made. Do nor skip anything, specially stuff you are totally SURE has to be right. Often that is where the problem is.
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Thanks for the suggestions. I reconnected everything from scratch ... still nothing other than a hum. Took the preamp to my technician who put it on the bench. Something is not working right. Not sure what, but he'll find out and hopefully that will solve the problem.