One of my 5231 has moist on the inside, shows on the lens.
Strange thing, it is under the carport, so never had direct rain as it is in the edge at least 2.5 meters away from the side.
I saw in the z5 thread the suggestion of opening it, use warm/hot air to inside and dry the gel bag in the microwave.
Is there anyone who did this already, and perhas has some good tips?
When you open it up, inspect that all the seals look good and no places in the seal has any deformities.
Its possible that changes in temperature is causing moisture to be drawn in around where the cable enters the cam.
I would open the cam up, only in a conditioned space with normal humidity levels, no higher than 40-50%.
Leave it open for 24 hrs, check to make sure it has a gel bag in the cam. You will want to gently clean the inside of the glass, with a soft clean cotton cloth. If you can, replace the gel pack with a new one, or place in an oven on it's lowest setting for an hour or so.
Possibly add an additional gel bag during assembly. Make certain the gasket lines up correctly when putting the halves back together.
Tighten each screw a little at a time so you get an even seal. Only re-assemble in the same conditioned space.
I would then take some RTV silicone and make sure the cable is well sealed going into the camera case.
Let the silicone dry 24hrs before putting it back in service.
If you have any doubts about the gasket, you can also use the RTV silicone in place of the seal. Use only a very small continuous bead.
Then carefully wipe any excess that squeezes out with your finger so as to be sure the gap is sealed.