On 2010-08-30, Jon Elson wrote:
Ignoramus5734 wrote:
That was am AMC 30A8 amplifier, revision T.

The chips on them mostly do not have markings, this one was a small
one in the middle of the motherboard.

I really like the drives, their simplicity, cost and support from
AMC. I do not know if I can guess the cause. But, possibly,
interference again is to blame.
VERY unlikely.
You mentioned ferrite cores to place on these cables. Would you
suggest any particular Digikey part number?

Sorry, I really don't have a part number. You might check old
computer cables for those bulges in them, those are big ferrite
rings for noise isolation. You want to run both motor cables
through the same core, so they are not exposed to the motor current
(the current in the two wires cancels out).

Jon, I bought some of those rings at digikey, they were
inexpensive. Item 240-2131-ND.

So you say, basically, just put a pair wires through the hole of one
ring, right?

i