Hi!
So I've tried again, this time making sure the serial shutter works. I cannot measure anything with a multimeter, but it might be because it is practicall tricky. However, when I only have the serial shutter attached to the camera (no USB) and start an exposure, it takes an exposure, and then of course reports an error. But the shutter must work becuase the shutter on the camera (including the mirror) is operating.
So. restarting everything, with both USB and serial shutter attached, I set the camera to enable mirror lock, set the mirror lock to a non zero value, and try. Now it actually takes an exposure. But it is not correct. There are 3 events: mirror lock, shutter opening, shutter closing+mirror down. Listening to the camera, it sounds as if the first event is mirror up+ shutter release. At event 2, where there just should be shutter opening, it sounds as if the mirror goes down. And nothning much happens at event 3 - however, frequently there is an "unspecified error" so at the time of event 3, instead I get a new event 1 for a new exposure.
The downloaded images does not reflect the exposire time either, but the fits header value represents the exposure time I've set. So: when I set mirror lock to 1 sec, and exposure to 45, I get an image that looks as if it is exposed 1 sec, not 45. But the fits header says 45 secs.
Further: when I have mirror lock disabled in camera, the small LED window on the camera counts the exposure time. When mirror lock is enabled, it does not count - as if it does not really take an exposure, which is what I believe (it closes mirror and shutter at event 2, instead of opening shutter).
I do hope this makes sense.
Log file attached.
Magnus