i have a whirlpool washing machine that i just bought used all cycles work except when it goes to rinse cycle?

my thought would be along the same line. disconnect the hoses at both ends and check the screens inside of the ends of the hoses. (that is if you have the screens.) make sure both WATER LINES ARE TURNED ON. sounds to me like one of them my still be off and when it comes to the rinse cycle and the machine calls for water, the hum you hear may be the solenoid valve for the water is open and if the water is off it's just going to hum. (that's telling you that the solenoid working but will keep on humming till the washer gets to the water level that you have set and then the machine will shut that solenoid off and the machine will start to agitate . check all of the settings to make sure they are going to do exactly what you want them to do and NOT what the last person had set them to do.

good luck to ya

From what you describe I would suspect that you have your water temperature knob set to wash in hot and rinse in cold, and the cold water doesn't feed into the machine for some reason. If this is the case try setting the knob to rinse in warm water and see if hot water is fed into the tub. If it does make sure the cold water tap is open. If so you may have a bad cold water solenoid valve. Good Luck

Here is the solenoid valve: http://www.repairclinic.com/PartDetail/Water-Inlet...

It sounds like the cold water isn't on or hooked up right.

The first thing I would do would be to check the belt it sounds as if it stretched.