I got an HEQ5 recently, and today got the upgrade to GOTO. Did the swap over of parts etc, and all went flawlessly (left the illuminated polar scope off - don't use it).
Turned it on, no problems, except after about 4 seconds of being on, I get an electrical high pitch hiss. I thought it may have been tracking, so turned that off. Nope, not tracking. Took off the covers again and listened, and it comes from the board (like a capacitor or something). Unplugged the board connector and replugged it, same deal.
Do these routinely hiss like this (quite high pitch), or should I be contacting Skywatcher/Tasco again to get a replacement board? It functions FLAWLESSLY in RA and DEC (superbly in fact), just the hiss is rather annoying/disconcerting.
I used to own one, and it only made high pitch noises when tracking. I'd probably be a little concerned. I'd be contacting Skywatcher to let them know what you've found. At least if it does go bang you've already bought it to their attention
This noise is nothing to be worried about - it is caused by microstepping (current control through motor coil is accomplished by chopping the applied voltage with high frequency. Because of that, the coil wires sometimes vibrate and produce the audible sound).
Hope Bogan is right there Lewis , strange noises like that are scary when you first turn on new equipement . ...
hope its all gonna work out for you .
Brian.
scary when you first turn on new equipement . 
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