I have a 8 GB Clip and I recognized recently that the display makes a tiny (really tiny!) noise, like its humming. When the display lighting shuts off, it stops, too.
Could that be a simple sign of wear or do I have to expect that it’ll explode someday? ;)
That noise is from a switch mode power supply. The display needs a voltage higher than the battery supplies so a boost converter is used to supply the voltage. It’s a common circuit technique to get high voltage rails for these portable devices off a 4V or lower battery. I design those kinds of chips. What is surprising is Sandisk used a switching frequency low enough to be audible. That’s not common these days but may have been done to keep power consumption and/or cost low. If you push enough power through a thin wire and at low enough frequencies you can hear it (been there, done that).
I would guess the noise either comes from tiny inductor in the Clip or even the display itself.
Message Edited by tnmats on 10-26-2009 02:37 PM