Dave Smith Instruments SYNTHESIZERS

Does anyone know if PEKs are susceptible to voltage fluctuations? The 
tuning of mine seems to change from day to day. If I have the 
oscillators set to C0, I may have to crank up the fine tuning to 45 or 
50 to get in tune. Sometimes even 50 isn't enough and I'll have to 
raise the oscillators to C#0 and then adjust the fine tuning.

Bernie