User Manual DDS200 Digital Demodulation System 070-9952-00

Maintenance and TroubleshootingSelf Test (QAM)The results of the continuously running selftest can be directly queried. Press thePRESET key, then the SERVICE key appearing on the screen and finally theSELFTEST key. By pressing the UP or DOWN key the screen can be scrolledto read the information about the individual module states. If in the MODE menuthe QAM–DEMODULATOR module has been selected, the following parameterswill be checked in detail:A): MICROPROCESSOR:0) BATTERY CHECK: OK/FAILURE. #B): CONVERTER: (selftest messages of the converter):1) POWER SUPPLY: OK/FAILURE; #2) SYNTHESIZER PLL: OK/FAILURE; #3) SAW TEMPERATURE: OK/FAILURE; #4) 5V REFERENCE: OK/FAILURE; #5) 33/24V REFERENCE: OK/FAILURE; #6) TUNER TEMPERATURE: OK/FAILURE. #C): QAM DEMODULATOR: (selftest messages of the QAM demodulator QD):8) POWER SUPPLY: OK/FAILURE; #9) OSCILLATOR LVL: OK/FAILURE; #10) AGC: OK/OUT OF RANGE;11) NOISE AGC: OK/OUT OF RANGE;12) DIG AGC: OK/OUT OF RANGE;13) TEMPERATURE: OK/FAILURE; #14) SYMBOL CLOCK: OK/UNLOCKED;15) EQUALIZER SYNC: OK/UNLOCKED;16) CARRIER SYNC: OK/UNLOCKED;17) FRAME SYNC: OK/UNLOCKED;18) I2C EEPROM: OK/FAILURE; #19) I2C BUS: OK/FAILURE; #20) 28MHZ CLOCK: OK/FAILURE; #21) I2C DEMODULATOR: OK/FAILURE. #Error MessagesThe EFA–Q continuously checks the main operating parameters. If one of theseparameters fails or is detected as faulty, an error message is displayed in thebottom line of the screen. This error message is derived from the self test, themessages being positioned in the following scheme according to their number.An error causes a “1” to be entered into the corresponding error number; if thereis no error, “0” will be entered. Only the messages marked by # are used for theselftest error code.DDS200 Digital Demodulation System User Manual 4–3