Help! Right Channel Dead

[Cpwill]

Just replaced shunt regulator board which wasn't working.  All resistance and voltages est with 10-15% or better, except filament is a bit low.  Left sound sounds great.  Right channel is dead except for hum/buzz (120 hz???).  Every thing measure identical side to side.  I have swapped inputs, tubes, outputs and it is not the feed from turntabl4, tubes or preamp/amp/s[eaker/cables down stream.  I resoldered the RCA's.  Any clues what to check next?

[Grainger49]

The hum/buzz can be either the ground or hot open from/to the phono preamp itself. 

Check these connections first and see if they give you near zero resistance from the RCA jacks to a component lead into the circuit.