Re: [Openbts-discuss] "assuming TRX is dead"

[Tomas K. <de...@vo...>]

 Jie,

in case of your problem, I refer you to this topic
http://sourceforge.net/mailarchive/message.php?msg_id=4B7D9F86.6080907%40volny.cz
and about 15 following
emails. Does the usrp_ffty.py output looks like this
http://sourceforge.net/mailarchive/attachment.php?list_name=openbts-discuss&message_id=4B7DCB70.2050403%40volny.cz&counter=1
?

I suspect that one of your RFX900 has damaged amplifier U4, like it was
on mine. Did you connected somehow any strong signal to RX of the issued
RFX900 ?
(I use 3dB attenuator from this moment on RX)

If the problem is truly in amp, it could be fixed quite easy, it's not
expensive
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=MGA-82563-G
I only recomend not to replace it "at home", you need some professional
equipment like microscope, soldering station etc.

Tomas


> Using usrp_fft.py one RX tunes correctly, the other fails to tune to
> my ARFCN. 
>
> The failed RX started out with a center frequency of 0MHz and failed
> to tune to anything that I tried. There were also a suspicious number
> of evenly spaced peaks displayed. 
>
> Would this pinpoint a particular failed component on the dboard?
>
> Regards,
>
> Jie
>
> On Mon, Oct 18, 2010 at 1:35 PM, Thomas Tsou <tt...@vt...
> <mailto:tt...@vt...>> wrote:
>
>     On Sun, Oct 17, 2010 at 10:18 PM, Jie M <jie...@gm...
>     <mailto:jie...@gm...>> wrote:
>     > Hi Thomas,
>     > It doesn't appear to be either of the eeproms, usrp_probe reads
>     them both
>     > correctly.
>     > For both RX A and B:
>     > --------------------------------
>     >>>> USRP Probe
>     > Name:
>     > Flex 900 Rx
>     > Converter Rate:
>     > 64000000
>     > Uses Quadrature:
>     > True
>     > Gain Range (min, max, step size):
>     > 0.0
>     > 90.0
>     > 0.0500000007451
>     > Freq Range (min, max, step size):
>     > 750000000.0
>     > 1050000000.0
>     > 1
>     > --------------------------------
>     > TX A and B:
>     >>>> USRP Probe
>     > Name:
>     > Flex 900 Tx
>     > Converter Rate:
>     > 128000000
>     > Uses Quadrature:
>     > True
>     > Gain Range (min, max, step size):
>     > 0.0
>     > 0.0
>     > 1.0
>     > Freq Range (min, max, step size):
>     > 750000000.0
>     > 1050000000.0
>     > 1
>     > --------------------------------
>     > Any other ideas?
>
>     Try running usrp_fft.py on each side tuned to the uplink frequency of
>     the desired ARFCN.
>
>      Thomas
>
>
>
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