Hi, I have acquired a Pentax MX. It is in near perfect condition. Problem is that the light meter is dead, totally. I have tried: 1) No corrosion in the batter compartment 2) Contacts look good 3) Using 2 A76 batteries 4) Tried different batteries 5) Inserted batteries both ways 6) I do have the film winding lever out the 20 degrees necessary to operate the meter 7) I am pressing the shutter release down 1/2 way I need some suggestions for obvious possibilities. I have repaired many cameras, just not that familiar with Pentax and want some likely possibilities before I tear the whole thing apart. Thanks!