Recently I purchased a Rek-O-Kut Rondine Jr. L-37. It's essentially a direct-drive broadcast deck. It's idler drive, heavy as hell and runs at only two speeds: 33 and 78. I am more interested in the latter. It's been through a few different owners who have committed a set of mixed restorations, and hack repairs.
It arrived with a few problems:
1. Left channel soft compared to Right channel
2. Lacks mono Cartridge
3. Ground Hum
4. All contacts filthy/oxidized in headshell
5. Solder joints iffy, wire caps sloppy
There was surely more wrong. Idler wheels may need restored. dampening inside the plinth would help. Spindle bearings are of mixed heritage... the Plinth itself is the work of a amateur carpenter. It's nicer than a dry fit box for mock up.. but it's not furniture grade either.
First problem. All connections inside the headshell are soldered. I needed to replace the cartridge so all these needed de-soldered. Turning over the headshell revealed that each individual wire was spliced. White to white, black to green, blue to blue, and brown to red. each had a raw uninsulated solder jopint in the middle. The mystery is that the teeny tiny wires already reached the cartridge. This was done so that it could be soldered on while the cartridge is outside the headshell. All this was to avoid buying $10 headshell wires. as a stop gap I coated the joints in liquid electrical tape. so I could install a new mono cartridge: Grado 78C.There should never be four wire caps in any connection. Solder something . Please. I cut the slop off, tinned, soldered, taped and then sealed in shrink tubing, added a spade connector to the uninsulated ground wire and then screwed that into the AM antenna of a rack mountable Parasound tuner. Dicey yes, but a well-grounded device. (Yes that screw in the back of the radio that says "ground" really is a ground.) I know this is not ideal. It's just all I can do until I mount a ground plate.
Replacing all the solder joints solved the softness. Cleaning the connectors with deoxit audibly helped as well. I oiled the platter, gave it a good wipe down and plugged that puppy in. Presently the ground hum is gone, the platter spins smooth and the 78s sound incredibly good. There is a bit of motor noise coming through though. This vibration is coming straight through the plinth. The solution would be to beef up the plinth and/or revisit the motor mounts. Future improvements are required but we are up and running... and playing an old Mariachi 78.Materials used: Weller Soldering Iron, solder, flux, spade connector, shrink tubing, a cheap lighter, one recyled spade connector, liquid electrical tape, electrical tape, tweezers, clothespins and a hemostat.