Installation Note N5227-90118 61
Installation Procedure for the Upgrade
Step 25. DC Continuity Test the LFE Board and Test Ports
The DC continuity test verifies that the LFE board is installed correctly and
does not have any opens or shorts in the DC path.
1.
Using a DVM, connect one test probe to the center conductor of the RF
port 1 (
1 1.85 mm
) on the front panel.
2.
Connect the other test probe to the port 1 bias input (
BIAS 1 IN
) on the
rear panel.
3.
Verify the DVM measures
<
10
Ω
.
4.
Repeat these steps for each of the other test ports.
Step 26. Position the Cables and Wires to Prevent Pinching
On the top side of the PNA, carefully position the gray flex cables so they can’t
be pinched between the covers and the rails.
On the bottom side of the PNA, carefully fold or push down the ribbon cables
and wires so they can’t be pinched between the hardware and the outer cover.
Ribbon cables and wires must never be positioned on top of hardware.
Step 27. Reinstall Front Panel Jumpers
Reinstall the front panel jumper cables.
Step 28. Reinstall the Inner Cover
For instructions, click the Chapter 7 bookmark “Removing the Covers” in the
PDF Service Guide
1
.
Step 29. Reinstall the Outer Cover
For instructions, click the Chapter 7 bookmark “Removing the Covers” in the
PDF Service Guide
If the DVM value is 0
Ω
or
>
10
Ω
, then something is incorrectly installed or there is
an open or short somewhere in the LFE board/cable path:
– Verify the cables installed in
“Step 18. Install the New Bias Tee
Combiner’s Semirigid Test Set Cables, the Blue Cables, and Install Cable
Clamps Onto the Ferrite Beads” on page 41
and
A71–74 Bias-Tee Combiner’s Blue Low Frequency Extension (LFE) DC Bias
Cables and Route Cables” on page 52
are connected correctly and not
open or shorted.
1. See