Andrew ATC200-Lite Guía para resolver problemas descargar pdf (Pagina 35)

Bulletin 639519 • Revision D May 2009 5-1

Section 5

Basic Approach: Isolate and Replace

When experiencing issues with a factory-installed actuator, Andrew recommends

returning the entire antenna with actuator rather than changing the actuator.

Proper installation procedures must be followed when installing and operating

RET equipment. Failure to assure installations are done properly by trained

installation personnel and to follow procedures discussed in this bulletin may

cause warranty for such products to be void.

Solving a RET problem does not always require technical expertise. It is often enough to isolate a

malfunction and replace the device.

If you ﬁ nd some but not all devices, you can connect directly to the device not found using RET control

cables that are known to be good. Rescan. If the device is still not communicating, replace the device.

If it starts communicating, add other devices one at a time, rescanning after each device is added,

until the error occurs. (For example, the problem could be an output connector of a junction box or an

actuator in a daisy chain.)

If you ﬁ nd no devices, by-pass a component (other than an actuator at ﬁ rst) and rescan. Continue

eliminating devices until the source of the problem is found. For example, remove the lightning protec-

tion unit and connect directly to the home run cable. If failure still exists, bypass the junction box and

retest. Continue until you ﬁ nd the malfunction. You can assume that the RET cable is good at ﬁ rst for

convenience. However, the RET cable could be the problem.

For cases where you are unable to contact any devices and smart bias tees are used:

1. Check that both top and bottom bias tees are installed and that they are installed correctly.

2. Check voltage out of smart bias tee (24 volts or 12 volts dc according to type).

3. Check voltage at end of coax.

4. Use another smart bias tee to eliminate the possibility of a bad modulator.

5. Make sure no device in the RF path will block the 2.176 MHz AISG signal (such as a diplexer) or

ground the dc voltage (such as a surge arrestor that does not pass dc voltage).

For cases where you are unable to contact any devices and a TMA and bottom smart bias tee are

used:

1. Check that both the top TMA and bottom bias tee are installed correctly.

2. Check voltage out of bottom smart bias tee (about 24 Vdc* between center conductor and

shell).

3. Check voltage at end of coax (about 22 Vdc* between center conductor and shell).

4. Use another smart bias tee to eliminate the possibility of a bad modulator.

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Andrew ATC200-Lite Guía para resolver problemas Pagina 35