Lionel 80W P/S Needs Rectifier

[BobbyDing]

Hey Folks,
I've got two of the above mentioned units that appear to need the rectifier repair I've heard so much about (but have never done). The trains speed up/down rather than the horn/whistle blowing. I'm sure of it being the p/s because the third supply I have runs the trains and whistles just fine. I have some electronics background, and so finding a rectifier is no sweat. I do want to be sure I install it properly though. Is there any online info for repairing these (a pic or two maybe)?

Thanks,

Bobby