1969 Bradford AM/FM Stereo Receiver Issues

[vortalexfan]

Hello everyone about a month ago I went though my Great-Grandfather's house to help clean it out to get it ready to sell, and I came across a bunch of old stereo equipment including a 1969 vintage AM/FM Stereo Receiver that was made by Hitachi but was rebadged as W. T. Grant "Bradford".

For some reason or another the left channel won't work on it, which is weird because I can get my signal generator to blow a signal through on the left channel just fine in the tape and phono mode by hooking directly to the respective input connections inside the radio, but when you hook a signal source directly to the RCA inputs on the back, the left channel won't work, it won't even work in tuner mode, with the exception of if I tune into some loud static or hash noise on the AM Band, then it will work in both channels but if its actually a station tuned in, then nothing will come out of the left channel, just the right channel, even in FM Stereo mode.

Any ideas as to what's going on here?

Thanks for your help.

Picture of the unit in question posted below.