Unit installation

OMRCPMICRO 59
Test Procedure - Trouble Analysis
All of the following procedures assume that power is applied to the MicroTech control panel and the circuit
break (CB1) is on. Some of the following procedures require the removal or replacement of the controller,
fuses, connectors, terminals or jumpers. Always shut off the power before making the required changes.
Microprocessor control board
The MicroTech controller contains three LEDs which aid in controller diagnostics and indicate the
microprocessor's operating condition. Table 10 details the operating condition indicated by these LEDs.
When power is first applied to the control panel, the red RESET LED will illuminate for approximately 3
seconds. During this time, the microprocessor is checking the control software and performing internal
hardware tests. When the tests are complete the red RESET LED will turn off and the green RUNNING LED
will illuminate indicating the controller's circuitry and software are operating correctly. The amber OUTPUT 0
ACTIVE LED is associated with the external alarm output on the solid state relay board and will be illuminated
during any alarm condition.
If the microprocessor status LEDs do not follow the normal sequence as shown in Table 10, there is a problem
with the controller. Likely problems include loss of controller power, corrupted software or the controller itself
may be defective. Following are troubleshooting procedures for the various symptoms.
Red LED remains on—If the red LED remains on after the 5-second self-test period, it is likely that the MCB is
defective. Disconnect the controller power by opening circuit break CB1 and check the field wiring. Observe
the controller's LEDs while reconnecting power by closing CB1. Sometimes field wiring problems can cause
the red light to remain on. However this can also occur in some instances if there is a power supply problem.
Refer to "Troubleshooting Power Problems" below.
Red and green LEDs off—If the red and green LEDs do not turn on after power is applied to the controller,
there is likely a defective component or a problem in the controller's power distribution circuits. Refer to
"Troubleshooting Power Problems" below.
Red LED does not turn on—Check for 18 VAC between Control Board power supply input terminals 1 and 2. If
18 VAC is present, check the power fuses mounted adjacent to the power connector. If this fuse is blown, it
should be replaced with a fuse of the same rating. If this fuse is not blown it is likely that the controller is itself
defective and must be replaced.
If 18 VAC is not present at the power connector, check for 24 VAC at terminals 25 and 27. If 24 VAC is present
here, transformer T4 is probably defective.
Table 10, Controller status LEDs
Green LED Red LED Indication
Off Off No Power to Controller
Off On Self-Test Failure or Power Supply Problem
On Off Microprocessor Operating Normally
Troubleshooting power problems
The Microprocessor Control Board (MCB) receives 18 VAC, center-tapped power from transformer T4. It then
distributes both 5 VDC and 12 VDC power to the various MicroTech components. A problem in any of these
components can affect the MCB and thus the entire control system. Power problems can be caused by an
external short, which can either blow a fuse or create an excessive load on the power supply. An excessive
load can lower the power supply voltages to unacceptable levels. Use the following procedure to isolate the
problem. Note that this procedure may require two or three spare MCB fuses. Refer to the panel wiring
diagram or the MicroTech Schematic as you proceed.
1. Verify that circuit breaker CB1 is closed.