M2 Antenna Systems RC2800PX-AZ, Руководство по эксплуатации

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TROUBLE SHOOTING CONTINUED
.
SYMPTOM: Rotator runs immediately after control box is turned on: This can mean that one of
your motor control wires on terminal #1 or #2 is grounded. When one of your motor wires is
grounded it completes the path to one side of the power supply. The micro processor normally
turns on a Darlington that in turn turns on the Mosfet that closes the circuit to ground and powers
the motor.
To test this, remove the motor wire from terminals #1. Using your ohm meter, see if this wire is
shorted to ground. If not, then the problem may be in the control box. The mosfet could be shorted
or the Darlington could have failed allowing 10 volts of drive to appear on the gate of the mosfet,
turning it on all the time. To confirm that the box is faulty, remove the motor wires. Using your volt
meter, measure from terminal #1 to #2. 35 to 45 vdc will be present if the box is faulty. Call M2 for
an RA (Return Authorization) number so we can be ready for your unit when it arrives.
Send it to:
M2 Antenna Systems Inc.
4402 N. Selland Av
Fresno, CA 93722
We NOW INCLUDE a copy of the power supply and conditioning and the motor control schematic
if you prefer to do the repair . Here are some helpful details.
The Dual Darlington chip is an eight lead package SN75452 and may be available at local elec-
tronic parts stores in your area. Digikey and other large suppliers also would stock this device. The
mosfet is a IRFI 530 (
I nternational R ecti f ier, I nsulated case) device and it can be crossed to sev-
eral devices with equivalent or higher voltage and current. The Dual Darlington is in a socket for
easy replacement. The mosfet is bolted to the chassis so the board must be removed to replace it.
Input from the micro to the Dual Darlington is pins 1 and 2 for motor control and the output is pin 3
When the unit is in standby, the input is high (5 vdc) and the output is low (under 1 vdc). When
and UP or DOWN button is pressed, the input goes low, allowing the output to go high (10 vdc)
driving the mosfet on and closing the circuit to ground on the motor.
The Dual Darlington also controls the motor direction relay. Input pins are 6 and 7, output is pin 5
so if your motor will not reverse, perhaps this half of the Dual Darlington is faulty.
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