Thank you for the update. Could there be an intermittent fault in the torch or at the Euroconnector? I know that it works now with parts from your 100A Mig, but maybe that swap-over corrected a problem ? If you swap back to original parts, is it still weak ? ( There speaks a typical computer engineer: "Put the flat tyre back on the car, to make sure that you changed the right wheel")
There are 6 diodes ? A centre-zero transformer only needs 2 diodes for full-wave rectification, so it must be two pairs of three in parallel, to share the current ( or its a 3-phase set ! ) So they are 50-Amp diodes - you could rule them out by using just two at a time, with a 20-30 Amp load.
Perhaps the headlight bulb load isn't enough to show up the problem. Yes, the "sampling" on a DVM means it will not show fast changes. An old-fashioned analogue meter is better.
Hi Eddie,
Yeah, it's most certainly not a torch or connector issue, I'd already ruled that out by fitting a brand enw mb15 I'd not long had, connector looked clean enough and so on. Poor current from both. Now both torch's work with the borrowed transformer and rectifier.
Yes your right, 2 sets of parrellel diodes, effectively making 2 large diodes.
I don't have an analogue meter these days but I have a scope handy (I am an RF engineer by trade ) so I could watch it with that, might be even easier to see exactly what the dip voltages are ?
Since the last strip of the rectifier stage the insulators have started to fall apart also so finding another machine to make one good one is fast becomming my favourite idea!