Minolta Hi-Matic 7sii aperture nonsense—any suggestions?
I bought a Minolta Hi-Matic 7sii 2 years ago. Never CLA'd it, but when I bought it it was in really good condition (well, the light meter has never woreed, but I'm happy doing sunny 16 and getting photos with the wrong exposure).
Recently, the aperture has stopped opening fully while shooting. This sounds like a stuck blades issue, but I don't think that's the case, because when I half press down the shutter button, it opens up the blades to nearly the right opening, before closing them again. On bulb mode, you can see that it really sticks to basically the same aperture no matter the f/stop I select. I don't even know how to properly describe this problem, so I'm struggling to get the right keywords to Google the problem. I've never taken apart or fixed a camera before, but I'm open to trying, particularly if it's a straight-forward or step-by-step fix (I don't want to be digging around in there exploring, I mean). [ETA: Based on the comments I will not try to fix this.]
I've attached a video to show what I mean. In the video, I start at f/16 and do a few half-presses before pressing the shutter button the whole way. I repeat for f/8, and finally f/1.7. You can see that the actual aperture at full-press increases between f/16 and f/8, but not between f/8 and f/1.7. During the half-presses, the aperture opens more between f/16 and f/8, and between f/8 and f/1.7.
What do you think? Is this a gunk issue, a broken part issue? Any suggestions for keywords I could search to learn how to fix this myself [ETA: I will not be trying to fix this]? Any fellow Minolta Hi-Matic owners experienced this problem?
Thank you, all!