ADC Dual Inline Tower Mounted Amplifier System manual 21

ADCP-75-214 • Issue 2 • September 2006

4.3Troubleshooting Flowchart (For Systems With Three-Port MHUs)

If directed by the flowchart, refer to the troubleshooting matrix in Section 4.4 or to the return loss sweep guide in Section 4.5.

START

• CHECK SUPPLY IS -56 to -20 VDC or +20 to +56 VDC.

	ANY	NO
	LIGHTS ON
	THE PDU?
	YES
RED	ALARM	OFF
	led

The red lead is connected to the higher potential.

•CHECK SUPPLY FUSE/BREAKER IS OK. (5A RATING)

•CHECK DC CABLE AND CONNECTION.PROBLEM

The red Fail led should come on when any MHU select dip switch is pushed to the down position. If the bias-t connection is not made.

								The red Alarm led should come on
								when any MHU select dip switch
OFF	MHU				MHU		OFF	is pushed to the down position. If
		led			led			the bias-t connection is not made.
								• CHECK DC CONNECTIVITY
			YELLOW			GREEN		TO		THE
			SOLID
								• CHECK MHU PORT FOR 18VDC.
								IF NOT PRESENT, REPLACE PDU.
								• CHECK BIAS-T CABLE FOR
									18VDC. IF NOT
								PRESENT,
								REPLACE BIAS-T CABLE.
PDU OR				ONE				• CHECK BIAS-T FOR 18VDC.
								IF		NOT
				PATH
CONNECTIVITY					TTA ACTIVE			PRESENT, REPLACE BIAS-T.
				FAILING
PROBLEM								• CHECK RESISTANCE OF
								FEEDLINE.
				REFER TO TROUBLESHOOTING MATRIX				-	LO OHMS OR
								SHORTED;
								PROBLEM TOP SIDE.
								-	HI OHMS OR OPEN IS
								NORMAL
								BUT ALSO MAY INDICATE A

DISCONTINUITY.

21401-A

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© 2006, ADC Telecommunications, Inc.