I recently bought a RB67 ProS with 120 (ProS) & 220 (Pro) back, & lens of course. No apparent light leaks on the camera/120 back (left film in the camera testing for leaks) & shot a few rolls with the 120 back with great results, besides a few quirks - The horizontal guides doesn't always retract when revolving to portrait, but finger taps to the base of the WLF will enable them to lower out of sight. Doesn't bother me too much. On the 4th roll w/120 ProS back, when I advanced to the next frame the red dial started to not disengage, a first lightly wiggling on the winder would cause it to retract. If it didn't the ME lever could enable me to take the next shot. Later the winder wouldn't pop back after advancing to the next frame, but engaging the middle lever on the back popped it back into place. When I loaded the 220 back, the film wound on fine, but after the first shot it would not advance. So another back is its way. But would it be acceptable to keep using these & simply use the middle lever to advance to the next frame after each shot using the film counter as a guide? With the red horizontal guides also not always retracting, is this related to the revolving back or signs of something else? Are there certain repairs/cleaning jobs I could do myself to keep this beauty running strong? (I know periodic upkeep is advised) OR if i wanted to send the body off to get tuned up, anyone have suggestions on where or who would do what's needed w/o costing an arm & a leg? (KEH prices seem pretty high for repairs) The backs are just eisier to replace, not worried about repairing those - unless it's something I could do Let's keep in mind I shoot mostly for fun at this time, & the rest of the camera has performed well so far & is in decent shape But I do want to keep it going. Any advice would be welcome. Thanks!