On Wednesday, August 9, 2017 at 3:59:53 PM UTC-4, Mr. Luddite wrote:
On 8/9/2017 2:15 PM, wrote:
On Wed, 9 Aug 2017 13:50:30 -0400, "Mr. Luddite"
wrote:

I think the problem is on the PC board in the control unit. It's
supposed to turn on, light up blue and display all the membrane switch
areas and labels. It doesn't. Has 12 volts but doesn't turn on,


That is the problem with most new things. Everything is on a single
board that may only cost a few bucks to produce in some 3d world
country but sells for hundreds of dollars. They seldom/never provide
any documentation about what is on that board. With a little knowledge
of what usually goes wrong, you might get lucky and find a bad part
you can replace on the board but they are bad about using parts with
no helpful markings on them.
I would start with the most rudimentary thing that is not working and
trace back to the 12v ... like those back lights. It may just be a
diode or regulator on the front end. (the actual controls may be 5v)
Are there any burned traces? Parts that look like they got hot?
I usually try to draw out what I see going along the traces and hope
it is not a multilayered board.
I got into this trying to fix gate controller boards. Fixed a few,
tossed a bunch. The chip that seemed to be the failing part on most
was not documented and the manufacturer was no help.



So far I have only seen one side of the control panel board. I plan to
remove it completely and inspect it. There are a bunch of tiny diodes
on it that are about the only things I can check (forward and reverse
bias) if I scrape away some of the conformal coating but nothing else is
testable that I can see so far. I think the problem *is* on the PC
board but a replacement is not available.


Once you get to where you can see both sides of the PC board, follow the power where it enters the board and look for a fuse onboard. It may not even look like a fuse. There are auto-resetting and one-shot current limit devices. If there is one it should be very close to the wire (or header) where the power attaches. Hopefully the board isn't multi-layer.