Troubleshooting guide

Bulletin 639519 • Revision D May 2009 20-1
Section 20
COBRA
™
RET System Diagnostics
20.1 Isolating the Malfunction
Finding the root cause of a failure is usually not necessary. It is enough to isolate a malfunction and
replace the device or cable. Refer to Figure 20-1 for an example of how the COBRA home-run control
cable or a spare control cable can be used to locate a malfunction. This example can also be used
for confi gurations with bias tees.
A 1 A 2
-
2
-
1
-
2
-
1
COBRA™ Homerun
Control Cable
Disconnected From
1
st
RET If Used For
Troubleshooting
COBRA™ Homerun
Control Cable or Spare
Cable Moved and
Connected to
Suspected Bad RET
Disconnect
all Adjacent
Cables
Disconnect
all Adjacent
Cables
Figure 20-1. Isolating the Malfunction.