Canon F1 mirror sticks only below 1/250th shutterspeed

Bit of a weird issue, this camera works completely fine with the exception of shutterspeeds below 1/250th of a second. At lower speeds the mirror will stick to the top and will stay there until the advance lever is slightly tapped or winded. This has nothing to do with the mirror foam (though it could be a result of it rotting into the camera somewhere). I have taken off the bottom plate and found that there is a metal piece that when moved slightly downwards also results in the mirror being dropped. I'm not sure if this piece is the solution or it just happens to be moving something else slightly which results in the mirror being returned downwards. I have attached a photo as well the direction im moving this metal piece that results in the mirror dropping. I couldn't find anything helpful online and tried to look through the f1 repair manual which got me nowhere unfortunately.

Cheers

Some cameras with cloth horizontal FP shutters, the closing curtain triggers the mirror to come down. I have seen the brake too tight, inadequate closing curtain tension, and gummed up mechanism responsible.

ic-racer said:

Some cameras with cloth horizontal FP shutters, the closing curtain triggers the mirror to come down. I have seen the brake too tight, inadequate closing curtain tension, and gummed up mechanism responsible.

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Do you know where in the camera the brakes would be found, I've checked the shutter tensions and they are both fine so it's not that

Alright for an update: the issue was exactly where i thought it was. I ended up loosening 3 screws that pertain to that part and then realigned it down a bit and retightened and wallah it no longer has that issue.

Hi, I have the same issue with my F-1. Which three screws did you have to loosen? I’d appreciate any help.