I have a CD player whose tray sometimes won't close at all, it just stays in the extended position. The end of travel SW seems good.
It has what I think is a standard 2-wire brushed 5V motor. And when I'm probing it on the scope, as it goes forwards, or backwards, sometimes it makes a nice looking square wave, +/-3.8V, other times, I see a few spikes, where the voltage returns to ~0V, and other times, I see a lot of chatter, between 2.8-3.8V lets say (I never properly measured yet). Thats w/ the scope rolling at 200ms/div.
I was probing the control signal in form an MCU, that tells the motor controller IC what to do, and it all looks normal, like a solid square-wave.
So if a brushed DC motor, has a commutator, and every so many degrees of rotation, it actually does short PWR to GND.....is that what I'm seeing sometimes?
Or is the motor wiring, or it's cap, shorting out sometimes ? Or does this sound like motor controller IC is failing ?
The motor measures about 2ohms, I can try and find 1 to swap in I could even measure the motor's current, see if it's bouncing around.
I can swap in a load resistor and see if the IC voltage stays clean then.
I can't remember probing motors before, whats this sound like ?