Picbits with ref to post #20, I think theres something amiss with your supply.
I also have a weir, 0-30v 2a or 0-60v 1a it is 2 identical isolated supplies which are either paralled or series'd.
Mine has a max o/p of 2a and it lights a 12v 21w vehicle indicator lamp immediatley no stress.
If yours is a 5a and it struggles something's wrong, when I got mine a couple of years back some of the cans had to be replaced to get a clean o/p, maybe yours has dried caps too.
I need to strip them down and replace the caps - they are getting on a bit now and I suspect the output cap has dried out over the years. It is perfectly fine for driving a constant 4-5 amps into a resistive load but doesn't like car headlight bulbs.