you want to monitor the ac input to the full wave bridge rectifier , make sure your reading some ac voltage, maybe your transformer can't handle the load of the bridge rectifier or maybe the rectifier has shorted diodes causing no voltage. do you have another transformer to use. don't forget the out side pins of the rectifier will be vdc volts dc out put so your meter must be on dc volts to read voltage!
let me know how you make out beb glad to help you any way I can!
Alan