Monday, 21 September 2009

Verdict: death by misadventure

"He died instantly, they say. No pain. He didn't stand a chance, the poor chip."

It seems the first stepper motor driver board's chip didn't stand a chance (and there may have been nothing wrong with the soldering after all). On inspecting the first board for damage, I noticed the semicircle drawing at one end of the chip's print on the board, and realised this was probably supposed to align with the dimple at one end of the chip. Unfortunately, being a complete electronics novice, and being unaware of the marking/importance, I had the chip the other way around. There had been nothing in the instructions to be careful about the chip's orientation. Guess we are supposed to know that. Well, I do now! (Funny how everything else was specified, though.)

I live and learn.


  1. It happens to us all even after 40 years of messing with chips. My first intergrated circuit victim was a Sinclair IC 10 amplifier chip (1968) I was 12 at the time.

    I started playing with electronics age 8 (1966) I was given a philips electronics set
    by a neighbour who worked for Philips.

    I also blew up a Gen3 stepper controller cant remember exactly what I did. The Motor power was still on as I was fiddling with it. I was not using 12V but 29V so its death was very swift.

  2. BodgeIt,
    Looks like I followed in your footsteps. I had a later version of the Philips electronics set and a Sinclair Super IC12 (which I still have), early 70's.

    The Allegro chips do not like the motor being disconnected with the power on. It makes them latch up and draw lots of current from the 5V rail.

  3. BodgeIt, that looks like fun! Wish I'd had my hands on something like that. They even made it link in with normal toys - I like the suggestion of using the light sensor with your toy train!
    The first electronicy thing I did was at A level physics, and we didn't get much hands on. I remember winding a motor, but that was about it. I learnt about electrics rather than electronics, other than the theory of logic gates.