On Sun, Jun 25, 2023 at 5:33 PM Rob Jarratt <[email protected]> wrote: > > Thanks Tony. I removed the mains bridge rectifier and found it measured short > across two of its terminals, so I am ordering a replacement. I tested the > PSU, without the mains bridge rectifier and without the diodes on the output > of the startup transformer. I got 24VAC on the output of the , the lamp > limiter bulbs did not light and the fan in the power switch unit turned. So > it looks like the startup transformer is actually OK. >
It's possible that the rectifier just failed. Or it might have been damaged because it had to pass too much current due to a problem in the main chopper circuit. I would certainly check the chopper transistor for shorts now. -tony
