Ah, now we're getting somewhere! Those multiple sets of contacts on the mic switch misled me into thinking the rig uses "electronic switching" but K1 tells me it's a relay which only requires one NO contact set to close in order to key the transmitter. Oh well, that's what happens when I don't have a schematic.
Yup, now you need to do something you should have done first off, clean the switches and pots. For this job I recommend DeOxit made by Caig, cleans like a champ and doesn't leave a lubricant residue to gum up on you later on. Then there are the relay and mic switch contacts, here you use a strip of heavy, rough paper slipped between the contacts and wiggled around while applying pressure to hold the contacts closed against the paper.
I always liked that microphone and have used them on several CB and Amateur rigs. It sounds great and gives best results when held about 6" from the mouth and off to the side slightly, "eating" it only makes it sound muffled and it picks up breath sounds rather easily.
Just a bit of advice as if you didn't see it coming, set aside that "slider" and operate legally. That having been said you'll save yourself other headaches, those things are unstable and if nobody has told you let me be the first, anything with the Siltronix name on it is pure crap. I cringed when I heard that name mentioned on the air and thought "it figures" when connected with garbage signals having chirps, a strong FM component and drift. Then the infamous 1011 was one of the original splatter boxes but I digress.
Now why don't you get yourself the other Browning and use the VFO for target practice? (;->)