Grabbed an old 2 meter mobile at a flea market for $10, no mic - how do I even tell if it works?

Done this rescue a few times and most of them came back to life, so here's how I check one before it ever sees a car battery. First thing, pull the top cover and look inside. You're checking for a burnt smell, scorch marks on the board, or any can-shaped parts with bulged tops or crusty leaked stuff around the base. Dust is fine, blow it out with some compressed air. Corrosion on the board from a leaking roof in the truck is what usually kills these, not age. If the inside looks clean, you're probly okay to power it up.

On your bench supply, set it to 13.8 volts if it goes that high, and most old mobiles want 10 to 15 amps available, so check what yours can do before you connect anything. If it's a little supply that only does a couple amps, it may fold over when the radio keys up, but that won't hurt the radio. Start with the supply current limit turned all the way down if it has a knob, then bring the voltage up slow and watch the ammeter. A healthy radio sitting in receive should pull well under an amp. If you see the needle slam to the max the second you connect, kill it right away, that means a shorted part inside and you just saved your fuse block.

No mic needed for a basic bench check. Receive is the easy half. If you've got another local ham or even a handheld, key up low power from across the room and see if you hear it. Some radios will also show signal strength on the display when it hears something, which tells you the receiver front end is alive without transmitting at all. I wouldn't transmit on it until you know the previous owner didn't beat on it, but receive alone tells you most of what you want to know.

Mics are the annoying part. They almost never swap between brands, the wiring is different on nearly every one and some carry the mic audio on different pins, so a random mic can do nothing or can even short the transmit line. Find the model number on the label, usually on the back or bottom, and search that plus the word mic pinout. Somebody has documented it. Then you can either hunt a used mic for that model or solder up an adapter yourself once you know which pin does what.

Cut power lead is no big deal, just solder on new leads and mind which one is positive, they usually mark it on the board or the back of the set with red and black.

Same experiance here with the mic being the tricky part. Pulled an old Kenwood mobile out of a barn sale last spring and the radio worked fine on recive first try, but I burned a whole month tracking down a mic that matched the plug. Ended up buying a second dead radio at another swap meet for a few bucks just to rob the mic off it. Check the accessory catalogs at hamfests too, guys sell used mics in boxes for next to nothing.

One thing to verify before you expect to hear anything on receive is that the radio actually covers the 2 meter ham band at all. A lot of the surplus mobiles floating around at these sales came out of commercial or police fleets, and some of those were programmed well away from where we hang out, so a perfectly healthy set can sit there quiet as a rock and convince you the receiver is dead. Find the model number, look up the frequency coverage, and if it is a commercial unit check whether it is even capable of being moved to our band, because not all of them are. I chased that ghost on a rescue of my own years ago and felt pretty silly when the manual explained everything.

Following this one since I did a similar rescue with an old CB set last fall. Mine powered up fine but the volume knob crackled like crazy for the first few minutes. Sprayed some contact cleaner in behind the knob and worked it back and forth a bunch of times and it cleared right up. If yours lived in a truck that long the knobs are probably grimy too, so don't assume the audio is dead when it's just dirty. One thing I'm still unsure about though, is it safe to key up briefly with no antenna or load hooked up, or does that risk cooking the output stage? I never got a clear answer on mine.

Update: pulled the cover like the first reply suggested and inside looked clean, no burnt smell, no bulged cans, just dust. Powered it up on the bench supply and it acutally receives. Volume knob was crackly at first so I tried the contact cleaner trick and it quieted right down. Still need a mic though, and yeah, the plug hunt sounds like the real project here.