I'm suffering from this issue for 3days now.
I'm currently working on with a robot which has 2 circuits of using 7.4V and 11.1V.
It also has 4 of 6V L12 linear servo motor. The motor works fine if the 11.1V circuit is turned off.
But whenever the 11.1V circuit is turning or turned on, the linear motors go crazy.
Since 2 circuits are totally separated except the ground, I assumed that
noise from the 11.1V circuit goes into the linear servo signal cable and makes the problem.
So I tried to twist the servo cable to compensate the noise, it didn't work at all.
Because of this issue I'm pretty much last these days.
Would anyone give me some help with this problem?