Specifications

MXI1002 OPERATIONS AND MAINTENANCE
5
5.1
5.1.1
5.1.2
TEST AND TROUBLESHOOTING
B
ASIC TROUBLESHOOTING TECHNIQUES
One of the best tools in troubleshooting is knowing what the nominal figures or typical values of the MXi amplifier
when it is at its normal performance. If a fault condition occurs, then you can compare the data taken previously
with the present conditions and come up with a reasonable conclusion about what is at fault.
The following describes some fault conditions and possible solutions.
No RF Output
• Check for proper power supply voltage and current
• Check for the presence of input signal to the modulator
• Ensure the modulator output is present.
• Check for potential connector problems causing either no drive to a module pallet (input connector) or VSWR
(output connector) problems.
• Check the fuses on the amplifiers.
Output Reduced to 25%
If the output is approximately 25%, a possible cause is a total loss of power from one of the amplifiers. The
MXi1002 transmitter utilizes a 3dB combiner to combine the power of the two RF amplifiers. If one amplifier
produces no output, half of the output of the operating amplifier goes to the output and the other half goes into the
reject loads. Similarly, most of the stages in the amplifier have redundancy built in them so that if one fails the
output of that stage will be reduced to quarter power (25%). In most cases there will be a blown fuse on the
offending pallet, indicating a shorted FET. From the control screen a simple measurement of the current drawn
by the amplifier in comparison with nominal readings will determine if this condition exists.
PUB11-018 Rev 0 July 8, 2011 11-018-9 MXi1002U Operations and Maintenance