Wonder if someone with experience on this receiver could help with something? I have been following some of the suggestions I have seen posted in various threads, but since there is no service manual available, I am finding that identifying some of the components is a little tough. Someone else had replaced the "driver transistors" with TIP31C and TIP32C types. I am assuming this means there are a total of 4 (2 @ of the above). I have these ready to go in but I am having trouble identifying the "drivers". Are two of them TR719 and TR720? Others? Initially, there was a signal in both channels, but with hum. I have replaced all suspect caps and this took care of the hum. There currently is no output in either channel, but I think this is going to be the "driver" transistors and idle adjustment. The output transistors check okay, but I have modern replacements just in case. Any other suggestions? Thanks for any assistance!