407 Torque Gauge  

I have a torque gauge in my 407 that is very "dim" for the first 10 minutes of a flight.  You can just barely make out the digital arc and the number readout.  After that it becomes as bright as the rest of the LED guages.  I'm guessing the guage needs repair, but if anyone else has had similar symptoms in their 407 gauges, let me know whether it was the sender unit or the gauge.  Greatly appreciated.