Turntable hum problem after demagnetizing

Everything is reconnected as before, including the ground. Tonight I pulled out an older phono cable to substitute and the hum is still there. That rules out the phono cable. I guess it's possible that the problem may be with the tonearm, but it sure a big coincidence that it happened right after demagnetizing....

thanks for the comments so far. All connections are good. Both channels play. I'll try disconnecting the cartridge tomorrow and see what happens. I did follow instructions exactly as specified. Also, this is a Benz made demagnetizer and I'm using a Benz cartridge - seems strange that they wouldn't be compatible.

Was aways for a few days, so just got around to disconnecting the cartridge. Hum still there, but slightly less - only slightly more now when touching tonearm, but very loud if I touch the hookup leads (red, yello, blue, green). I will try rehooking the leads tomorrow - as Paul2240 suggests - I have otherwise disconnected and reconnected the phono cable from both ends. The ground wire on the phono cable looks to be undamaged and all other visible wiring looks undamaged. I don't think the AC is the problem - there are 4 other components hooked up to the circuit - no issues.

So, I took my whole rig into the local high end audio store and the tech checked it over with an ohm meter. He did finally isolate it to the cartridge. Ouch.....
Also a careless error of mine - the hum is actually only in the right channel, in my panic, I thought it was both. I've contacted Garth from Musical Surroundings, and I'll see what he says.