I have a very old oven 2nd or 3rd hand, no turntable, but a glass tray... The cover which is beige and a clear bubble all fell down as a single unit, exposing a lg fan. is the oven still safe to use? Likely to cost too much to have somebody look at it or do repairs, Maybe at one time were plastic pins holding it the the roof, but I see and have found nothing in the unit. See no labels or markings otherwise, then number inside door liner below.