Betapack (1) Flicker

[twohats]

A few channels on our Betapack dimmers flicker when the output is at or near zero.

The effect is influenced by the output on other channels, it can also be reduced or eliminated by raising the level of the flickering channel to 10 or 20%.

I was considering adjusting the preheat pots, would this be a good idea?

 

Robert

[KWR88]

My best guess is a fault with the low voltage rail being dragged around and causing the ref rails to be pulled down as well.

this could be a problem with the output of the transformer or possibly the 470uF smoothing capacitors on the low voltage supply rail.

[twohats]

Thanks for that. As soon as I can I'll get a scope on the supply rails and see what they look like.