Yashica Flash-O-Set II Repair

This is only a guess, and I'm assuming the 'II' version is the one that does not have the crest on the front of the face plate.

The rear screw looks like it's one anchor point for the top plate. I think the two side screws adjacent to the strap lugs, have a dual purpose. They are likely to be overly long 'through screws' and hold the lugs in place, and coincidentally also anchor the top piece to the camera frame. If that's the case, they'd need to be removed entirely to let the top plate slide up. And... The lugs may be loose and fall out once the top is pulled up, and will need to be secured temporarily when the top is returned. Most of the Japanese camera maker's top plates that I've come across don't ordinarily use brazing or soldering/welding for strap lugs or similar attachments to the top cap itself from inside/underneath. If there's no slide-slots to clear the top getting past them when it's pulled up, I've found they're usually separate pieces that aren't screwed-in using their own threaded post, or permanently attached.

It's difficult to tell from crappy auction pics, but it might be possible that the top cap may have an 'apron' that is covered on the front side by the outer leatherette cover. It may need to be peeled back to reveal any anchor screws underneath. I'd think that would be the logical place to hide them, if the 2 side screws weren't the correct - or only - anchor points

The 'I' version is considerably different in construction, so if that's the one you have...

I think this version might use a 2 piece top cover, with the front section being a separate piece. There looks to be a parting line running right in front of the back edge of the flash bulb's ejector button. It seems like that whole front-facing section acts as a bezel for the bulb socket, the finder window, and the meter panel - and once its freed, it will slide forward. My guess is that all four screws - 2 on each side - need to be fully removed.

The side screws seem to serve two purposes. The upper set - next to the lugs - are likely a set of 'through screws' again. The lower screws may serve as the primary anchors for both the front bezel and the vertically-lifted top plate rearward of the bezel as yet another set of through screws. The rear screw on the metal section seems to be obvious that it's there to anchor the top plate - while the screw on the plastic finder window cover likely attaches it directly to the frame.

There might also be secondary screws underneath the front bezel that are additional anchor points for the top plate, assuming my guesses on this version are accurate.