Could be you have a bad 6AU6 in the IF based on what you posted in this thread:
http://www.videokarma.org/showthread.php?t=266957
The filament voltages should be within about 10% of each other. Either one of those tubes is not really a 6AU6 or it's bad (I'm thinking a heater cathode short) or there's some bad issue with a socket or wiring.