| Products > Test Equipment |
| Teardown, Repair & Analysis of a Rohde & Schwarz FSH3 3.0GHz Spectrum Analyzer |
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| Hugoneus:
In this episode Shahriar examines a faulty R&S FSH3 100kHz – 3.0GHz Portable Spectrum Analyzer. This exceptionally dirty unit does not power on and is missing a power supply and battery. After verifying the correct operation of the battery charger circuit and keypad the problem is traces to a damaged SOT-23-6 MOSFET device which is part of a fly-back DC-DC converter. A replacement MOSFET with a lower current rating proves to be a failure as the device fails on startup. A higher rated MOSFET resolves the problem and device begins to operate correctly. The block diagram of the system as well as a detailed block diagram of the RF section is presented and correlated with the teardown of the RF section. The super-heterodyne down-conversion circuits and components are examined. Watch the video here: [51 Minutes] youtu.be/qD05ZFVplE0 More videos at The Signal Path: http://www.TheSignalPath.com |
| dr.diesel:
I'd be tempted to fab a custom metal bench enclosure. Excellent video as always. |
| ElectroIrradiator:
Ah, you posted the video in here. Your first replacement MOSFET blew up because it was a P channel device. :D |
| Hugoneus:
--- Quote from: ElectroIrradiator on August 04, 2015, 02:08:42 pm ---Ah, you posted the video in here. Your first replacement MOSFET blew up because it was a P channel device. :D --- End quote --- I noticed that I actually showed the wrong datasheet I think. I believe that the part that I used was a N-channel, but rated only to 400mA and not 1Amp as the PMOS datasheet indicated. :) |
| tec5c:
Another great video Shahriar. It's always the highlight of my day/week/month when a new video is posted up on the signal path. Keep up the good work. (insert thumbs up emoticon as Windows 10/Microsoft Edge doesn't seem like it's capable!) |
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