NY2KW
Newbie level 4
I acquired an R&S SM300 signal generator has some output issue only between certain level ranges independent of selected frequency. The self-test program passes all internal testing. The following is a description of the symptoms and perhaps someone can advise if I should be focusing on the attenuator or power amplifier? On my recently calibrated HP 438A, the SM300 output seems linearly accurate from -100dBm up to -26dBM but at all levels tested it is exactly 10dBm lower than as set on the front panel controls, i.e., at -26 dBM my power meter reads -36dBM. As soon as I set the front panel controls up 1 dBm to -25dBm, all signal is lost (or it is less than I can measure ~-120 dBM). Signal remains lost until I reach a setting of 0 dBM where the signal returns but my power meter only shows -36 dBM and increasing higher than 0 dBm doesn’t do anything – signal still there but at -36dBM. The SM300 should go up to +13 dBm.
The R&S service manual is unhelpful other than saying replace the board… no schematics and nothing on component level. I would like to get some idea of how to trace through the problem and where to start - attenuator or the wide-band amplifier section. I have contacted several repair services – most say they don’t have enough technical info from R&S to repair – while 2 others want 2x the current asking price for a functional used SM300.
Any advice appreciated.
Jerry NY2KW
The R&S service manual is unhelpful other than saying replace the board… no schematics and nothing on component level. I would like to get some idea of how to trace through the problem and where to start - attenuator or the wide-band amplifier section. I have contacted several repair services – most say they don’t have enough technical info from R&S to repair – while 2 others want 2x the current asking price for a functional used SM300.
Any advice appreciated.
Jerry NY2KW