I have 3 Tascam 112 taperecorders, they have been unused for over 20 years, i replaced the belts and the pinchrollers, they work great now, but... with two of the three 112s there is a VU-meter not responding. When i play a tape with the output volume at 10 i see 1 of the meters that works, and i see the overload led blink... the other meter is not responding, the overload led however is also blinking. The meter is not blocked, when i put the tapedeck at it's side both meters sway out together... what can cause this and how do i solve this ?