SQ-A ME prism trouble

I recently acquired ME prism from KEH, BGN. Since I live in Europe sending it back is not an option so I hope you guys can help me a bit with it:

It seems that ME prism always adds +2EV, no matter what back I put on it or if I try with the new battery.

Okay, if I want to shoot 400asa film I can always dial 1600 on the back and get the right exposure value, but with anything above 800asa it is just impractical, just takes time and I got it for street type of shooting mainly, candid stuff and etc. so...

any of you fellas know if there's a way to re-calibrate it, or have any other idea what might help?
It's a CDs based prism so I guess it drained a bit, but I also hope there's some nice way to set it's EV properly.

thanks!

The compensation dial is working properly?

my mistake, sorry with bothering with this thread, I'm used to different communication between the camera, prism and the lens.
I simply cleaned the contacts between prism and the body a bit and now it gives right EV.

...and it worked for few minutes, now it's back to 'normal'. cleaning contacts again didn't help. perhaps someone 'repaired' it and set cds wheel +2 by mistake.
sorry for relentless bumps.

Check the battery. It might be on its last legs.

Steve

oh, that was one of the first thing I did, I get same +2EV with fresh one. also checked with all 4 lenses I have at all ƒ values, it gets the ƒ-value read from any lens.