Pentax KM light meter repair

[roxybubbles]

Hi i was given a Pentax KM and was told the light meter may not work, iv tried putting a battery in the camera but nothing seemed to happen. iv been shown in some cameras there like a sponge strip at the upper side of the cameras inside and was told that if this is damaged that could have a lot to do with the light meter not working. iv knottiest on my camera this sponge is damaged but not a grate deal. i was wandering if anybody knew anything about this ( the sponge strip) as id been intreated to know more about it and also if its possible to fix the light mater in my Pentax light meter my self??
much appreciated =)