On 04/08/2015 13:01, Bob wrote:
Hi Folks,

I'm not an EE, so would really appreciate someone educating me a bit on
this.

Trying to fix kids toy.

Very simple electrically, just a battery going to one of those
small, cheap, probably a PM type, dc motor that does nothing but spin a
pointer.

For some reason, they have a diode in one of the leads to the motor.
(in series with one of the leads)

The Diode must be defective, for if I by-pass it, the motor spins just
fine.

Can't imagine why the Diode.

Hard to believe that it is for any RF suppression due to the brushes
that are apparently on this really small dc motor ?

Anyone have any thoughts perhaps as to for what purpose the diode
was included ?

Thanks,
Bob

There seems to be a few types of small diode constructions that are
guaranteed to fail an overcurrent by going open circuit. Cheaper than a
wire-ended fuse , and as a plus, battery reversal protection