Nautel XR12 Troubleshooting Manual

Also see for XR12: Installation manual Operation and maintenance manual Preinstallation manual

Contents

XR12 Troubleshooting Manual Detailed Circuit DescriptionsIssue 3.0 2009-07-28 Page 2-13Dump circuitThe dump circuit, consisting of DUMP potentiometer, U2C, U13A and U13B, is not used in thistransmitter.Remote interface PWB (NAPI83/01A)See electrical schematics Figures SD-15 through SD-18.The remote interface PWB performs the following functions:• Buffers all external remote control inputs and remote status/alarm outputs.• Provides buffered, analog sample voltages proportional to the B+ supply voltage, total dccurrent, audio, forward power, and reflected power for external monitoring.• Conditions the audio (analog or DAB) input's gain and provides filtering and modulationprotection.• Provides monitoring samples of the transmitter's RF output (both analog and DAB). Themagnitude of the analog sample is automatically adjusted to ensure a relatively constantvoltage, nominally 1 V rms, regardless of RF output level.• Provides the connection for the system's external interlock circuit between TB1-1 andTB1-2.Remote inputsRFI filtering is provided on all control input lines to ensure transmitter operation is not interrupteddue to RF pick up on control lines. Opto-couplers are provided to buffer/isolate the external circuitsand prevent any unwanted transients from affecting transmitter operation. The position of shortingSINGLE/DIFF jumper E19 allows the control inputs to be configured to operate from a single-endedor differential input. Refer to “Control and monitoring” section of the XR12 Installation Manual for adetailed description on single-ended versus differential inputs.