I bought 4 of these boards recently, and I’m just putting them through their paces now after some basic testing.
They will only supply about 0.5A without a heatsink, so I have arranged them in a square and strapped a video card cooler to the top, with channels cut to avoid shorting the Vbb capacitor, and the current pots sticking out the sides.
While testing this arrangement I discovered that on one board, there was a mere one ohm of resistance between enable and ground! Luckily enable is negative-asserted. On the other 3 boards, there is about 900k. According to the schematic, this should be around 100k due to R6. None of the boards show any continuity between this pin or ground and the heatsink.
I have yet to ascertain whether this is due to something I’ve done, or if the boards came like this, although I can’t imagine what I could have done to cause this.
I’m pretty sure these boards are still usable in my application with this issue.
Any ideas how this might have happened, or what I should check or try?