I recently hooked up my 20 year old MFJ 941 and found it was not up to par. I opened it up and found several of the pop rivets were preventing a good ground on the SO239s. I drilled out all of the rivets and replaced them with screws, star lock washers and nuts. I soldered an additional bus to all of the SO2392. Upon further inspection, I found a cold solder joint where the bottom of the inductor connects to chassis ground, a bent inductor wire almost touching one of the tap wires, and an intermittent variable capacitor. I corrected the bad connections and cleaned the cap with contact cleaner. While I had it open, I removed the crappy 4:1 voltage balun and replaced it with a home brewed 1:1 current balun, so I no longer need to use my external balun for ladder line. 20 years ago, the tuner worked great, but they do deteriorate after sitting for 8 or 10 years. Now it's like new again.