1998 S-10-E Electric Truck
EV1 System 110 Inverter/Drive train

I found the following modification in the buffer wiring harness for the radiator
cooling fan which indicates a failed fan buffer assembly.

The assembly's PNs =
(on wire = 711) - (on buffer =  27003265 717_) - ( on wire = 712)

Unfortunately this is a typical failure and the part is no longer available from
GM.  Therefore the only option is to de-epoxy the assembly, dianose its failure
and repair the original part.

The following are a few pictures of this projects progress.  More pictures to
follow  as progress is made.  2009.01
This shows the unit
as found after
purchasing the
vehicle in 2007.
Note the lower right
corner of the uni.  It
shows and unusual
indentation which is
later found to be the
area of an over temp
failure event.
Our initial attempt
was to chip away at
the epoxy base but
we quickly learned
that this would not
yield exceptable
results.  We later
came across a
progess to slowly
soften the epoxy and
successfully cleared
the board for repair.

This process took
nearly a week of
soaking, removing
material, and
repeaded efforts.  
Painful but
eventually worth the
results seen below.
Top view.  Here is the
basic board at the
final stage of expoxy
removal.

It should be noted
that in this picture the
board is missing a
number of parts that
were removed for
replacement.
Bottom view.
Well, then an
unexpected option
came up.  Someone
Well, then an cents.  
We normally
unexpected option
never give up a
project, but other
project, but other
projects were calling
projects were calling
and we just had push
the easy button.


We did make some
more modifications,
however, to the new
NOS buffer when it
arrived.  As noted in
the pictures to the
right, we added a good
sized aluminum heat
sink & ceramique to
the original set-up in
hopes of saving it from
the previous part's
fate.

The following are
some different shots
of the new set-up
.
Resistor scales and
written in on this
document.