Robin you must be very unlucky with that camera then, because i sort of abuse mine by leaving it outside in the sun and sometimes rain and it doesn't fail or even ice up at -20 or more.
My QHY5 is has lost almost all colour on the body because of the sun
I just had an look at the Sbig website but i dont see any mechanical drawings of their models.
Mr QHY has had more full mechanical drawings than most manufacturers on the forum or on his website.