OH NO! let the smoke out....

Dang, I cooked my poor little Arduino Mega. There was a problem with my SSR puck, I assumed the knot heads would put a snubber diode in any DC puck but I was wrong and the inductive kick from the motor fried it (stuck on). That part I get. In the schematic you can see I added the snubber. Mega OK at this point.

So I removed the 120vac thinking that perhaps that would let the puck release. I plugged it back in and the resulting surge to charge the ripple cap and start the motor was too much and took out the fuse ...... AND MY MEGA ?!?!?!

Was a 6 amp fuse cuz the motor is only 1/3 hp and the Mega power comes from a small wall TX style power supply (9v). Even though the drawings show a transformer it is a small switching type regulator.

The only think I can think of was perhaps I should have kept my 90vDC ground plane seperate from the Mega's ground plane. Other than that, I am stumped as to how the puck frying would take out my Mega. I always though ground was ground, isn't it?

Can ya'll see anything else obvious?

Keshka
(uh oh, guess I don't know how to put a photo in...researching)

(uh oh, guess I don't know how to put a photo in...researching)

Get a free photo hosting site like Flicker. Up load you image to it and get the URL to it. Then paste the URL in between those brackets.
When you do we can have a look. By the way what model 'Puck' do you have? Is it an AC or DC output? If it is AC then you shouldn't have a diode in line as this is a short on negative parts of the cycle.

perhaps I should have kept my 90vDC ground plane seperate from the Mega's ground plane.

Where is the 90V DC coming from? With that sort of voltage I would advise using an opto isolator.