This one came to me with the very fine Super Takumar 1:1.4/50 lens. Unfortunately, the camera also arrived with a shutter that intermittently would not fire.
I played with the camera's settings to try to understand the shutter problem and found that the shutter worked better with the aperture auto-stopdown feature turned off, and it seemed to work faultlessly with no lens mounted. So, time to search the web for possible explanations.
After quite a bit of digging, I came across the likely answer at the Pentaxforums.com web site to the apparent shutter problem, which in reality was a compatibility issue.
"The SV came in an early and a late type. The latter has an orange 'R' on the rewind knob which tells that the camera can use the 50mm f/1.4 lens (which protudes farther into the camera than all other 50mm lenses)"
So, that green R designating the rewind knob is clearly pointing to the source of the difficulty. That does not explain exactly, however, how the misfit lens was interfering with the action of the shutter. My first idea was that the little flapper that activates the aperture stopdown was implicated in the problem. On further thought, and considering the clicking sound of the misfiring shutter and the likely train of events in the process, I decided that it was likely the instant-return mirror hitting the lens that was stopping the normal shutter cycle.
With the lens off the camera, I brushed Ronsonol lighter fluid onto the mirror levers that were visible in the interior of the camera body. Then, I mounted the slightly slower, but still very good 1:1.8/55 Super-Takumar from my old Spotmatic. I worked my way through the full range of shutter settings many times without encountering any hesitation in the shutter's action. The final test, of course, was to shoot a roll of film in the H3v. I dropped in a roll of Kentmere 100 and took the camera on my usual walking route through Albuquerque's Old Town. I only got a couple images I haven't shown here before, but I'm very happy to report that I came home with twenty-four perfectly exposed images.
The H3v story for me provides some interesting insights in several regards. I think it points to the fact that Pentax and the Japanese camera industry at the time of the introduction of the H3v was undergoing a pace of discovery and technological development of a vertiginous nature. The complexities were such that some compatibility issues were inevitable. It also shows that Pentax and other Japanese companies were up to the challenge, and explains much of their long-time international dominance of the industry.
My own encounter with the H3v also provides some insight into my approach to camera restoration. My tendency is to look for the simplest, non-destructive solutions to common problems encountered with the old cameras. My objective is to get the equipment working well enough to make pictures reasonably close to what might have been expected when the cameras were near new. I know that is a stance that will rankle with people who have more of an inclination toward mechanical expertise, but I'll happily admit that I'm a photographer first, and a camera repairman only as a last resort. Of course, this approach only works in the short term. If I need a camera to be ready to perform on a regular basis I think a better option is to seek the help of someone who has real skills.