Sounds like a switch issue to me.Once you go past the low setting,all is well.That should be the whole multifunction "stalk",not cheap.I would get used to using the high setting then easing back to low.
Never heard of a 'pulse board' ? Where is it? How hard to replace? In a salvage yard, what do they normally run for? How do I TEST to see if it is a switch or a pulse board? Does anything else run off the Pul. board? I was wondering if that would tell me if it was bad....