Nautel Vector-LP VR125 Technical Instruction Manual

Contents

Vector-LP Radio Beacon Transmitter Technical Instruction Manual Page 5-13Section 5 Maintenance and Troubleshooting Issue 1.1NOTEWhen an RF synthesizer PWB configuredto operate from an external RF drivesource is installed in a transmitter, itsfrequency synthesizer must be operationaland its BCD switches must be set toproduce the assigned carrier frequency.The synthesizer's output is used to obtainthe 2(PDM) output which ultimatelydetermines the host transmitter's pulseduration modulation frequency (PDM).(f) Perform RF drive symmetry testingand adjustment procedures (see4.3.6.9).5.8.1.2 INTERPHASE PDM DRIVER PWBREMOVAL/REPLACEMENT(See 5.8 and 5.8.1 first)(a) Remove the protective cover over theinterphase PDM driver PWB beingreplaced (A6 or A9). The cover issecured using seven sets of M3mounting hardware.(b) Remove and retain four sets ofmounting hardware for the interphasePDM driver PWB being replaced (A6 orA9). If the exciter interface PWB is tobe removed (see 5.8.1.3, remove bothinterphase PDM driver PWBs, ifapplicable, and go to 5.8.1.3.(c) Pull the PWB(s) away from the exciterinterface PWB (A2). It may be helpful togently pry the connector loose with ascrewdriver.(d) Install the new interphase PDM driverPWB by reversing the steps above.(e) Verify that shorting jumper E1 isinstalled in the D position.(f) For dual side transmitters, perform theEqualizing Exciter Gain adjustmentprocedure (see 4.3.6.10). For a singleside transmitter perform theCalibrating Transmitter Output Poweradjustment procedure (see 4.3.6.3).5.8.1.3 EXCITER INTERFACE PWBREMOVAL/REPLACEMENT(See 5.8 and 5.8.1 first)(a) Remove all connections to the top andbottom of the exciter interface PWB.(b) Remove and retain 13 sets of mountinghardware for the exciter interface PWB.Remove the PWB.(c) Install the new exciter interface PWB.Re-install connections to the top andbottom sides. Use the connector taglabels or the connector matinginformation after Table 8-2 to determineproper connections.(d) Set all shorting jumpers as per theoriginal exciter interface PWB.(e) Re-install the RF synthesizer PWB(s)removed in paragraph 5.8.1.1 and theinterphase PDM driver PWB(s)removed in paragraph 5.8.1.2.(f) Re-install the exciter/control assemblyin the transmitter by reversing the stepsin paragraph 5.8.5.8.2 Exciter Monitor/GeneratorPWB ReplacementSee 5.8 first. Remove the exciter/monitorgenerator PWB (A7 and, for dual sidetransmitters, A10) as follows.(a) Remove and retain four sets ofmounting hardware for the excitermonitor/generator PWB being replaced.(b) Remove all connections to the excitermonitor/generator PWB.(c) Install the new exciter monitor/generator PWB. Re-install connections.Use the connector tag labels or theconnector mating information in Section8 to determine proper connections.(d) Perform the following calibrationprocedures: 4.3.5.5, 4.3.5.6, 4.3.5.7,4.3.5.8, 4.3.5.9 and 4.3.5.10.