Jay Summet via EV wrote:
I've opened it up and found (at least) two MOSFETS blown out right near
the logic board. Photos and lots of text here:
https://www.summet.com/blog/2017/01/08/curtis-1231c-8601-500a-pwm-dc-motor-controller-teardown/
Doesn't look too bad; it looks fixable. :-)
Be sure to clean *all* the soot off. It is conductive. If any at all is
left behind, it provides a preferential path to encourage future arcing
and shorts.
One MOSFET on the power board (Q13) is different from all the others.
That one is a series pass regulator. It knock pack voltage (B+) down to
24V to run the internal logic.
First, it has 3 pins connected to the PCB, while all of the others only
have 2 pins, with the third middle pin soldered to a ring terminal and
connected to the heatsink via the mounting screw.
It should also have an insulating sheet, to isolate its drain from the
heatsink.
Second, it is a Vishay IRFP254 instead of an IXTH50N20.
Mine has an MTW20N20 in this location. That's a 200v 20amp MOSFET. I'm
not sure why they used such a big part, as the supply current is pretty low.
If anybody has a schematic for power or logic board that would be appreciated.
I do. Printed versions, and ORCAD schematics. I can mail a copy to you
(send me your address off-list).
--
Teaching children to program goes against the grain of modern education.
Just imagine the chaos if they learned to think logically, plan, create,
implement, test, and execute!
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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