Marconi 2955A radio test set repair component level, calibration checks, walk & talk.

Repair of Marconi 2955A radio test set with complaint of keypad issue, & stock fault of 200MHz oscillator, & check over with full calibraiton checks. Functional walk & talk, explanation of the modules & circuit theory. Here we dignose the fault on the keybard & replace a capacitor in the 200 MHz oscillator circuit, replace the air filters & clean the PSU, followed by full checks of all test parameters using various instruments such as the Marconi 6200A Microwave Scalar / VNA for accurate RF gen level checking, Agilent ESA Spectrum analyser to check dynamic range of step attenuator & Aeroflex spectrum analyser to check RF Gen levels down to -120dbm, RX Mod gen level tests, Signalling tests, Sequental, DTMF, CTCSS, DCS, POCSAG, furthermore we carryout TX power testing, AM & FM mod gen tests, TX Deviation, frequency error, & freq counter free run tests, AF Gen output & external mod input. We check the RF Level overload warning for the 1w RF port & check the instruments dynamic range of all RF levels on both N & BNC ports across the oprerational frequency ranges of the instrument.