User Manual

MCA9129-90MCA9129-90-A Installation & Service Manual

044-05060 Rev. C 6-3 July 2001November 2002

the outer connector shield is not damaged. When installing the amplifier, do not force

the amplifier into the slot. Gentle even pressure is all that is needed to properly seat the

amplifier.

B. Improper seating of the amplifier.

1. Ensure the amplifier thumbscrews are properly tightened.

2. Try seating the amplifier in another subrack slot.

3. Try seating the amplifier in a subrack in another sector.

6-2.5 DC FAIL Illuminated

If an amplifier is in DC FAIL and the LPA Disable LED is illuminate, then one of the four amplifier

DC voltages is either out of tolerance or not present. Return the amplifier to the factory for repair.

6-2.6 6-2.5 FAN FAIL Illuminated

If an amplifier is in FAN FAIL, then the one or more of the amplifier’s cooling fans has failed. Re-

place the fan.

Model MCA9129-90

MCA9129-90-A Amplifiers

A single A fan failure does not cause the amplifier to shut down.

Two failed large fans cause the amplifier to shut down. These amplifiers have a small fan on

the front lower panel. The smaller front fan’s performance is not monitored.

6-2.7 6-2.6 LOOP FAIL Illuminated

Loop Fail is always accompanied by LPA Disable LED illuminated. This may be due to

1. Inability of the amplifier to maintain a 180° phase shift between the first and second loops.

2. A damaged error amplifier. This can be caused by

A. Out of band spurious or intermods being applied at too high of a level at the amplifier in-

put port. An input band-pass filter may be necessary to correct this problem.

B. Disconnecting amplifier RF output cables while the amplifier is still turned on. Always

turn the amplifier off when moving output RF cables from the hatch plate to test equip-

ment and back again.

3. Improper power balance between amplifiers in a given subrack.

A. Ensure the amplifier thumbscrews are properly tightened. Reset the amplifier by mo-

mentarily pressing the Reset button on the amplifier front panel up.

B. Try seating the amplifier in another subrack slot.

C. Try seating the amplifier in a subrack in another sector.

6-2.8 6-2.7 LOW PWR Illuminated

Low Power is always accompanied by the LPA Disable LED illuminated. This is due to the gain of

either the internal preamplifier or main amplifier being 0.5 dB (typically) or more below the ampli-

fier specification. The amplifier should be returned to the factory.

6-2.9 6-2.8 LPA DISABLEStatus LED Illuminated Only

1. LPA DisableStatus LED only illuminated indicates that the amplifier RF section is disabled.

This may be due to the following: