On Mon, 25 Nov 2013 20:07:16 -0700, Tony Hwang wrote:

What if the new board blows up when replaced?

That's why I only want to spend the $104 to replace it.
It *does* have overload circuit protection besides.

Are you planning to protect it some how from that occurring?

I've done plenty of smoke tests in my life.
This will be one of them.

BTW, looking at arrow marking on diode
can yu tell which direction current electron or current flows?
Can you tell which lead is the cathode or anode?

Heh heh ... here is a board I built many years ago to test
impedence (j omega stuff). I wired a diode to house current!
You'll notice the diodes. Particularly, you'll notice that the
nichrome wire resistor has the same impedance as the the capacitor.
(I couldn't find an inductor of a large enough size.)
FRONT: http://farm6.staticflickr.com/5491/1...41b67f1e_o.gif
BACK: http://farm4.staticflickr.com/3800/1...928f65c1_o.gif

Also notice this circuit, where I used 555 timers (I think that's what
I used), way back in the 80's, to measure capacitance and resistance
simply by counting the flash rate ...
FRONT: http://farm8.staticflickr.com/7362/1...3e84efa3_o.gif
BACK: http://farm3.staticflickr.com/2893/1...fa50a070_o.gif

I did those circuits in the early 80's but, of course I know
about the shape of the diode curve and which is the anode and
which is the cathode.
http://sub.allaboutcircuits.com/images/03256.png

Everyone knows this basic stuff... even we accountants.