Outback Power Systems FX Series Installation Instructions

FX Circuit Board Replacement Instructions

There are three circuit boards inside the FX inverter. Normally, only two of
these boards are candidates for replacement; the FET board (large board that
includes the battery terminals) and the control board (smallest board that includes
the microprocessors). In some cases, however, the AC assembly (the “L”-shaped
boards that include the AC terminal block) is defective.

Tools required to service the FX are:

• #2 Phillips screwdriver

• 3/8” flat blade screwdriver

• 4mm hex wrench (included with the boards shipped to you)

• 10mm deep socket on a 12” extension with ratchet

• 10mm wrenches (2 of them would be nice)

• Rubber-band wrench (usually used for opening jars)

• Flashlight

• 9-volt batteries (three if you have a 12V or 24V FX, six for a 48V FX)

The FET board is the “brawn” of the system. It processes all of the high
current to and from the battery. This board contains the drive and overcurrent
protection circuits. In general, when an inverter fails, it is often the power FETs
that go. The FX is designed such that in the event of a FET failure, you replace
only the one assembly. There are two green LED’s on the FET board that help to
diagnose problems.

The control board is the “brains” of the inverter. It contains all of the
processing power as well as the unit’s memory. The processors and memory are
programmable and therefore possible to upgrade. It may be possible in the future to
download new code into the control board in the field, but for now we will have to
live with board swapping. There are either 15 or 20 (depending on the age of the
board) green LED’s on the back of the control board to help diagnose problems
with it.

The AC assembly is the I/O (Input/Output) portion of the FX. The AC
assembly consists of the AC board and the connector board. They are soldered
together to form one “L”-shaped assembly. This AC assembly will rarely require
repair or upgrade.

Once you have determined that the FX must come apart, use the following
guidelines to disassemble, repair, test and reassemble the unit. Repair should be

Installation & Programming Manual FX Circuit Board Replacement Copyright 2003  OutBack Power Systems, Inc.

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able to be done in the field although installers may want to take the FX back to the
shop (where the power actually works) for verification testing.

STEP 1:

Turn off all breakers feeding into and out of the AC and DC leads. Disconnect
the AC and battery connections. Unless you want to get really frustrated when
you try to put the unit back together, take the extra 2 minutes to remove the unit
from the wall so that you can work in the “gravity assist” position. (You may
really hate life if you don’t do this)

STEP 2:
Remove the red and black plastic nuts with the rubber-band wrench (Figure 1). It
doesn’t scratch or dent anything. Break down, go to Sears and get yourself one, (It
opens jars too!) or else use a flat bladed screwdriver like you are loosing up a
conduit locknut.

Figure 1

STEP 3:

Use a #2 Phillips tip screwdriver and remove the six screws inside the AC
wiring compartment (Figure 2, Phillips). These are 6-32 x ½” stainless steel pan
head screws (In case you lose any). Before getting into the unit you need to
make sure you do not have a static charge built up on you or your clothes. The
safest way to accomplish this is to stand naked in a mud puddle while
disassembling the inverter. Another method would be to make sure you are
wearing only 100% cotton clothes. Cotton does not build up a static charge. In
addition, ground yourself by touching something like a water pipe, electrical
ground conductor etc. in order to bleed off any charge. Static can destroy

Installation & Programming Manual FX Circuit Board Replacement Copyright 2003  OutBack Power Systems, Inc.

Page 2 Rev 2.0 10/26/04 Tel [phone] Fax [phone]

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boards. The form of static that is harmful is much less than what actually
makes sparks. 30 volts can damage parts, so don’t take chances and don’t
handle any boards unless static control measures have been taken.

Hex

Phillips

Figure 2

STEP 4:

Pay attention to this one or you’ll hate yourself later! Use a 4mm Allen wrench
(included) to remove the 8 stainless steel socket head cap screws that connect
the top to the bottom casting (Figure 2, Hex). The FX has a fan mounted to the
top cover. It plugs into the FET board. If you pull the top cover off without
thinking, it will rip the wires right out of the connector. (This is where you will
start swearing and your customer will become alarmed!) If this happens, you
have two choices. 1: get new Molex crimp terminals and the special crimp tool
to correctly fix the problem, or 2: solder the wires onto the sockets that are still
attached to the mating connector on the FET board. Hint: cut some of the plastic
away first so you can get to the pins. The red wire goes towards the bottom
casting (the latch side of the connector). Figure 3 gives you an idea how long
the wires are. There are two small O-rings that fit into slots of the battery
terminals. If they aren’t in their slots, they may be stuck to the underside of the
top cover. Remove these small O-rings so they don’t get lost. There is also a
very large O-ring that travels the perimeter of the chassis. This doesn’t need to
be removed but if it comes out it should be reinstalled before the top cover is
put back on. If this O-ring is too small, it can be stretched. The last thing that
should be noted is the square piece of “Nomex” attached to the underside of the
top cover (see Figure 3). Sometimes this piece falls out or is loose. If this is the
case please use some silicone to glue it back in place. Make sure it is fairly dry
before attaching the top cover.

Installation & Programming Manual FX Circuit Board Replacement Copyright 2003  OutBack Power Systems, Inc.

Page 3 Rev 2.0 10/26/04 Tel [phone] Fax [phone]

900-0042-1 19009 62nd Ave NE, Arlington WA 98223 USA