After my many adventures in purchasing FF33’s I decided to write a little buying caveat emptor tutorial… I hope this proves helpful!
FF33 are still relatively plentiful, having been used by quite a few European countries including Switzerland, Norway and Sweden well into the 1970’s.

Current prices range from $60 to $125 with some being offered for the ridiculous prices of $200 and up. Check the telephone or the photos of the telephone well. Almost always the telephone will be missing the carry strap and the patch cord. Many will be missing the hand crank, look for it either attached to the end of the telephone on the generator shaft or stowed in its pocket on the top of the telephone under the handset.
Check the handset; sometimes it will be missing the carbon speaker and receiver cartridges. And in instances the microphone side will be replaced with a receiver end as the microphone cover with its elongated cup is more easily damaged. The other regular handset problem is the bridge of the handset being cracked. The cabling to the handset is often frayed or damaged at the exit due to the rubber cable grommet being deteriorated. The handset PTT button should function freely. The plug on the cable will have 4 or 5 pins, the middle pin was unconnected. Later in the production the middle pin was omitted to save materials and production time. The same is true of the socket on the telephone.
The battery case is another piece that is often missing. This is easily discovered by lifting the battery compartment cover. The battery case is designed to protect the telephone internals from any leakage by the corrosive battery. A missing battery case isn’t fatal to operation of the telephone and isn’t a piece that isn’t on view when the telephone is on display.
Test the battery connector nuts, sometimes these will be corroded in place. Depending on the amount of the corrosion damage it may be possible to free them. However do not use heavy force as these terminals are mounted on a bakelite insulator plate that will not stand stressing.
If you have the opportunity to remove the telephone internals, do so. This is done by loosening the two capture screws on the top of the body. Depending on the production date of the telephone it may have metal side panels. Most telephones will not have too much dirt or dust inside dure to being well shielded. However if the telephone was stored in a moist environment or immersed in water the internals may be ruined. Rusting or bubbling or evidence of repainting on the top panel of the telephone is a good sign to walk away from a purchase, except for scrap or spares.
The only other butchery I’ve seen in telephone internals is where someone attempted to disassemble the components. The wiring harness is soldered and well run such that all of the parts must either be unsoldered or removed in a very specific order. Watch for cut wires between components, a sign of the some amateur disassembly.
Remedies
If the generator crank is missing it is easy to make a replacement, it may not be as pretty but workable. The generator shaft is 8mm x 1.5mm thread. The quickest is to tap one end of a piece of aluminum tube and bend it into a crank shape. More time consuming is to machine a substitute.

For fixing a cracked handset bridge, epoxy resin is best. Disassemble and clean the handset thoroughly. Then fasten the two pieces together in a jig to hold them properly. Use peel ply on the exterior to keep the finish clean. Case cracks in the bakelite can be handled similarly. Use a reverse mold of an undamaged section and fiber cloth to help in forming the case if the damage is extensive. Dye may be added to the resin help disguise the repair.
Repairing a frayed handset cable end can be accomplished by shortening the cable. Repairing wiring in the telephone requires care in stripping and soldering to make sure of a good connection. The wire is cloth insulated. So stripping is best done with a razor cutter, straggling threads can be burned back with the soldering iron. Use muriatic acid to clean the wires and terminals, neutralize the acid with soda after. All terminals must be soldered for a good connection, do not use crimp terminals, the electrical connection will not be good and introduce noise. Also most crimp connectors are too large for the small gauge of the wiring in the FF33.