Installing the External Power Plug
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Locate a place near the battery contactor for the external power plug with convenient access,
protected from heat and exposure, and permanently mount the SB-50 plug.
●
Prepare two lengths of primary wire to connect the positive lug of the SB-50 plug to the battery
contactor, and the negative lug to the airframe ground.
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Touch solder and install the connector lugs. Instructions are included with the wiring kit. It is
recommended to install the included protective cover for the plug.
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Once the external power plug is installed, polarity tested and labeled, the GPU is ready to use.
Connecting GPU to Aircraft
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Connect the GPU input cord to a grounded power receptacle, 90-240VAC, 50-60Hz.
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Connect the output cable (dual 8-gauge cable with Yellow SB-50 plug on each end) to the GPU.
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Turn GPU power switch ON, observe as proper voltage stabilizes on the output display.
●
Connect GPU output cable to SB-50 plug on the aircraft, observe that the airframe is energized
and shows a stable load of less than 35 amps. If voltage or current load are not as expected, or
GPU status warning light comes on, disconnect the GPU from the airframe and investigate the
problem.
SAFETY TIP: Using the GPU during preflight allows a thorough inspection of all systems and
lights, without depleting the battery. In fact, if the battery is in-circuit, the GPU can provide a brief
“top-off” charge for the aircraft battery!
Status Indicator
The GPU incorporates a status indicator between the volt/amp meter and the output connector.
Indications are interpreted as follows:
OFF Power Switch OFF, or no AC input power
GREEN
ON or powered, normal operation
FLASHING GREEN
Auto-shutdown engaged
FLASHING RED
Fault condition – see troubleshooting table for more details
Automatic Shutdown Timer
The M1435-EXP features a programmable timer to automatically shut down the GPU after a period of
time in use, as selected by the user. This is to prevent the GPU from inadvertently being left on for an
extended period and potentially overcharging the aircraft’s battery, if in-circuit with the GPU.
A 10-position rotary switch on the back panel determines the duration of continuous operation. Each
number represents ½ hour. This switch is factory set at 5 (2.5 hours); make adjustments with a small
screwdriver. To disable the auto-shutdown feature, set the switch to the 0 position.
To reset the timer and restart the GPU after auto-shutdown, cycle the power switch OFF then back ON.
USB Mobile Device Charging
Two convenience USB charging ports are provided on the rear panel of the GPU. These provide a 5VDC
output, up to 2A total combined, suitable for charging many portable devices like phones and speakers.
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Model M1435-EXP Manual P/N 752-790, Rev 20211029
