Nautel VS300 Troubleshooting Manual

Also see for VS300: Quick start guide Installation manual Operation and maintenance manual Preinstallation manual Troubleshooting manual

Nautel VS300 Troubleshooting Manual Manual pdf 36 page image

VS300 Troubleshooting Manual Responding to alarmsPage 1-28 Issue 6.0 2014-11-013.Pre-amp PWB replacementSee Figure MD-1 in the Mechanical Drawings section (Section 6) of this manual.1. Remove the transmitter’s top cover. Retain hardware for re-installation.2. Unsolder and remove the six solder connections to the pre-amp PWB (A5). They include awhite, 24 AWG wire (to pad A), a white, 16 AWG wire (to pad B), and two coaxial cables (topads C and D and F and G).3. Remove the two M3 screws, Belleville and flat washers securing the clamp that secures FETQ1 to the heat sink.4. Remove the four M3 screws securing the pre-amp PWB to the heat sink.5. Remove the pre-amp/IPA PWB from the heat sink, noting the orientation.6. Clean the heat sink surface with a soft cloth and non-abrasive grease remover. Do not useany material that may scratch the heat sink surface.7. Obtain the replacement NAPA27A pre-amp PWB from the station spares kit, if purchased.8. Spread a small amount of thermal compound (Nautel Part # HAG39, from the stationspares kit), in a thin, even layer, on the bottom surface of the pre-amp/IPA PWB palette.9. Secure the pre-amp PWB on the heat sink using the four screws removed in Step 4, notingthe correct orientation. Do not tighten the four screws at this time.NOTE:FETs are static sensitive. Handle the pre-amp PWB in a static protected manner.CAUTION:When installing FET securing hardware, you can damage the FET case if you fullytighten one screw while the other is loose. Avoid this by alternately tightening thetwo screws.