[sdiy] Trimpots

[Dave Manley]

On 8/9/2011 5:45 AM, Harry Bissell wrote:

> Offhand, I didn't understand what the trimmers in the (was it) Emulator are for, or I'd try to
> be more helpful. I think you should probably look at some circuit points on the scope and
> twiddle the pots, try to figure out what they are supposed to do...

Here's the schematic

	http://www.fileden.com/files/2006/10/13/285304/E-II%20PS.JPG

Looks like R110 controls the initial frequency on a uni-junction transistor
oscillator that sets the switching rate.  The other I'm guessing (R109)
tweaks the switching rate to compensate for variation in the input
voltage (AC) level.

With a scope (or frequency counter) and a variac this could probably be sorted
out.  Someone could also easily damage their equipment or themselves by touching
the wrong thing in the high voltage part of this supply.