Nautel GV30N, Troubleshooting Manual

Page: 53 / 365

GV30N TROUBLESHOOTING MANUAL RESPONDING TO ALARMS
VERSION 0.1 2014-11-01 PAGE 4.1.45
PA Resistance Checks
1. Using a digital multimeter, check the continuity across fuse F1 on the suspect PA PWB.
 If the measurement is an open circuit, replace the PA PWB (see “PA PWB Replacement” on
page 4.1.44 ).
 If the measurement is short circuit (near 0

), proceed to Step 2 .
2. Using a digital multimeter, measure the resistance between each gate lead of the FET and the
metal flange of the FET.
 If the measurement is less than 8 k

, replace the PA PWB (see “PA PWB Replacement” on
page 4.1.44 ).
 If the measurement is between 8 k

and 17.5 k

, check the other PA PWBs for a failure. If
none of the other PA PWBs have failed, replace the original suspect PA PWB.
 If the measurement is greater than 17.5 k

, proceed to Step 3 .
3. Using a digital multimeter, check the continuity between each drain lead of the FET (positive meter
probe) and the metal flange of the FET (negative meter probe).
 If the measurement is open circuit, the PA PWB is OK and does not require replacement.
Continue troubleshooting and suspect a problem with an associated PWB.
 If the measurement is not open circuit, replace the PA PWB (see “PA PWB Replacement” on
page 4.1.44 ).