Products > Test Equipment
Teardown, Repair & Analysis of a Rohde & Schwarz FSH3 3.0GHz Spectrum Analyzer
(1/10) > >>
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!)
Navigation
Message Index
Next page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod