I just replaced my HXT900 servos with D933MG Digital Metal Gear Servos from HK. The HXT's were working fine, but jittering a tad when my FPV transmitter was powered on, and these servos are supposed to be a lot better for this, indeed there was no jitter at all when I powered them up with the Vtx powered up as well.

However, the first time I powered them up, there was a loud squealing, which I thought at first was from the Corona rx, but listening closer I could tell it was from the servos. It abated some after a minute or so, not seems to only come on when I put the servos full over and hold it there. They chirp a bit but not too bad.

A quick google shows that this is probably something I should not be concerned about, as digital servos can squeal from time to time, I just wanted to make sure, that's all.

Analog servos buzz (50hz refresh rate) digital servos squeal (100hz+ refresh rate). That is why digitals are better, they are repositioning themselves faster which is why the buzz turns into a squeal.

schu