It is up to each builder to determine
which modifiactions to perform on their own helicopters. If your
ship has the jumpers as installed from the factory in the overhead
wiring panel, all engine systems could shut down simultaneously
if a short circuit should occur. The following photos and explanations
show how I fix this problem to provide true redundency to the
electrical power to the engine components controlled by the overhead
panel.
Step one is to disconnect the
battery and then clip back the plastic zip ties that bundle the
wires together so that you will be able to pull the wires to one
side to get to the three jumpers (D,E, & F) that go between
Fadec 1to Fadec 2 to Ign 1 to Ign 2. These jumpers connect both
the primary and back up systems together and will cause those
systems' power supply breakers to blow in the event of a short
circuit in the alternator wiring (B).
Once you can get at the wires
you can easily see the three jumpers. I cut the first jumper (D)
as close to the Fadec 2 fuse as possible to give me a longer lead
to work with. The middle jumper (E) between Fadec 2 and Ign 1
is cut in the middle and the last jumper (F) is cut as close to
Ign 1 as possible to give a longer lead on the Ign 2 side to work
with. The below photo shows me cutting the Fadec 1 to Fadec 2
jumper (D). Wire (A) is the 30 amp lead coming from the battery
to one of the two the 30 amp Battery fuses, (B) is the wire that
comes from the alternator and connects to the 30 amp battery fuse
on the load side so if there is a short in that wire, it takes
out the 30 amp fuse, then through the jumpers takes out the other
30 amp fuse cutting all power to the engine systems. Wire (C)
is the power wire coming from the load side of the 30 amp battery
fuse to the line side of the Ign 2 fuse.
The below photo shows
me cutting the jumper (E) between Fadec 2 and Ign 2 in the middle
of the jumper.
The photo below show
me cutting the jumper (F) between Ign 1 and Ign 2 as close to
the Ign 1 fuse as I can cut it.
In the photo below the
jumpers have been cut and the ends stripped of insulation so that
the two new jumpers can be attached. I solder an 8" 14 gauge
jumper between wire one (Fadec 1) and wire 3 (Ign 1). I solder
another wire between wire 2 (Fadec 2) and wire 4 (Ign 2).
After I solder one end
of each jumper to Fadec 1 (Wire marked 1 on above photo) and Fadec
2 (wire marked 2 on above photo) each, I slide two pieces of shrink
wrap onto each new jumper so that I can insulate both ends of
the jumper after the final soldering is completed.
The photo below shows
the two new jumpers soldered onto the cut jumpers. One wire
connects
wire 1( in the photo with marked wires ) to wire 3 and the other
jumper connects wire 2 to wire 4. Once the all of the
joints are
soldered, I slip the shrink wrap over the solder joints and
use a heat gun to shrink the pieces in place. The short stubs
of the
jumpers that were cut (seen in the photo below) can have a
piece
of shrink wrap placed on them and then heat shrunk in
place.
Once the two new jumpers
are installed and tested by turning on all systems, I use new
zip ties to securely bundle all of the wires in the overhead panel
together.