19th February
written by Todd Harrison

This is Part 6.  It is the final installment because I did get the power supply working. You may want to first follow (part1), (part2), (part3), (part4) & (part5).

Somehow I or the crap designed circuit damaged one or more of the chips during part 1.

I started by testing my extra PWM chip (UC3843N) on a bread board. It was a new chip which was never used and it was testing fine until I turned the wrong knob and let out all the magic blue smoke. I took out the PWM chip that was in the control board since part 1 and it tested as bad. In fact Vcc was being shorted to ground. That explained a lot.

I ordered another PWM chips from Digi-Key and after installing it the controller and motor started working. I was having some speed regulation issues which I attributed to not having the heat sinks connected. At that time, which was the end of my video, I assumed the controller was functioning the best it could considering its poor design.

After delivering the motor and controller to HeatSync Labs one of the clever hackers there looked into the speed regulation issue which was not clearing as I thought it would once the heat sinks were mounted. He found another chip on the board that was bad, one of the op-amp chips. It was a chip I too had replaced over a year ago so something was killing the chips on the control board quite easily. This control board was such a pile of crap from day one.

It is working marvelously now so if you’re ever in Mesa Arizona swing by HeatSync Labs and try out their great little mini lathe. Maybe make yourself an aluminum chess piece or two.

Thanks for joining!

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