It's not hard to CLA a Compur shutter of this type, but if you want to send it out, Frank Marshman did a fine job on my Perkeo II. Check in the links area under camera repair, and you should find a link to a good site with instructions for repairing various folding cameras and some Compur shutters.
The film transport system:
The Perkeo II has double-exposure prevention and a film counter. If you open the back, the roller to the right of the film gate meters the film advanced. To fire the shutter, the film has to be advanced to a new frame and the shutter has to be cocked.
Notice the lever on the back of the camera to the right of the shoe. This is the counter reset.
To start flip the lever clockwise to the right. If it doesn't flip, then manually turn the abovementioned roller to the left until it stops, and then the lever will flip. Put a fresh roll of film in the feed chamber on the right side, thread the leader into the takeup spool, and then lift up the film advance knob and insert the takeup spool on the left side. Turn it a bit so the paper is taught, and close the camera back. Look through the red window and advance the film until you get to frame "1", then close the red window shutter and flip the counter reset counterclockwise, and the mechanical counter should read "1." From here on in, you can use the mechanical counter. You should be able to get 13 frames per roll reliably, but this is not particularly advantageous unless you shoot slides, because you can't get 13 frames on an 8x10" contact sheet.
Other things to notice--
When you open the camera, the lens standard might not click into place. You can nudge it a bit until it clicks. This is a common situation with the Perkeo II.
With the camera open, looking down from the top toward the rear door just in front of the shutter button there's a metal tab with a hole. You can attach a cable release here.
When you close the camera, push the two buttons on the door to release the standard, and push the button on the bottom plate so you don't wear out the latch.
On the bottom of the door, there's a little metal stand with an arrow. Pull it down to set the camera flat on a table.
