Products > Test Equipment
Rohde & Schwarz CMU200
<< < (68/71) > >>
RBBVNL9:
All,

Getting the IQIF card working in my CMU200 turned out to be no less than a quest. Basically, three things went initially wrong:
1: Errors in R&S documentation, leading me to faulty wiring,
2: CRTU-B7 is NOT equal to CMU-B17,
3: Need for “firmware update after board change”. 

I also learned quite some other things that may be relevant for CMU users, like that in specific circumstances, the instrument simply swapped the I and Q lines (!)

But now I got all up and running, and made a video documenting it.

https://youtu.be/VUljs46ViIk


F4IUJ:
Hello,

I got myself a CMU200 for not much money. I use it mainly as a generator and a spectrum analyser. Unfortunately, I had a bit of an accident as I was using it as a signal generator to calibrate a small qrp rig VFO and I sent by error a 37dBm pulse into the front end of the CMU200 RF3 which is limited at 13dBm in my case  :palm:

I suppose that will teach me to put an attenuator even I don't think that I need one! But beyond this, is there a chance that I can repair the front end ?

Kind regards

Yannig

PS : thanks Rudy for the videos, I watch them!
Bicurico:
If you search this forum you will find posts regarding the repair.

It involves opening up the front end module and replacing some IC's - can't remember which ones.  There are a total of 4, one for each input port.

Definitely doable, but quite some work and not totally noob-proof. For one, you are dealing with SMD components, then you need to desolder one component containing Berlium (if I recall correctly). This is why you have a safety hazard sticker on the front end module (or should have).

The white powder inside the module should just be aluminium oxide - not that dangerous. Try to vacuum clean it, but do not (as I did) blow on it...

The other option is try to buy a front-end module or a broken CMU200/CRTU. Chances are, though, that the purchased replacement is broken, also.
Bicurico:
This is the thread I was referring to: https://www.eevblog.com/forum/repair/rohde-schwarz-cmu200-repair-(analyzer-levels)/

Check this link of one of the posts: http://wunderkis.de/cmu200/rawpic/

It is the "C4" component you need to replace.

The RFP 50-17 AMZ component is the one you need to dessolder to get to the back of the PCB. This is the one containing berryllium: https://nj.gov/health/eoh/rtkweb/documents/fs/0222.pdf
F4IUJ:

--- Quote from: Bicurico on June 26, 2023, 01:17:00 pm ---This is the thread I was referring to: https://www.eevblog.com/forum/repair/rohde-schwarz-cmu200-repair-(analyzer-levels)/

Check this link of one of the posts: http://wunderkis.de/cmu200/rawpic/

It is the "C4" component you need to replace.

The RFP 50-17 AMZ component is the one you need to dessolder to get to the back of the PCB. This is the one containing berryllium: https://nj.gov/health/eoh/rtkweb/documents/fs/0222.pdf


--- End quote ---

Thank you, that is really helpful. There is one thing that puzzles me, if I see properly there is just one "C4" component but I seem to have damaged just one channel. Shouldn't it be a part specific to RF3 in my case ?
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod