Re: [Discuss-gnuradio] find_usrps "No USRP2 found."

[Steve Glass]

Hi,

Further to my problem trying to discover the USRP2. From a cold start
(the USRP2 was left without power since my last posts) I configure the
GigE port using ethtool and enable TX pause frames (this seems to be
necessary magic on my PC). I then run this at the command line:

while true; do clear; find_usrps; sleep 1; done

and watch the output. For the first 30 seconds or so I get the device
MAC address then "No USRP2 found." From a real cold start this takes a
little longer so I got as far as running usrp2_fft.py -f 925M and that
guarantees I lose connectivity. Have removed the power and lid on the
USRP2 and see U12 which is a large-ish package and gingerly touch it. It
is indeed quite hot. Once the device has stopped responding even
removing the power for a few minutes is not enough to make it functional
so a heat-related failure of the PHY chip seems plausible. Before I go
about requesting a return authorization is there any other diagnostic I
can perform?

Many thanks to all (especially Marcus) for your help

Steve


Steve Glass wrote:
> Marcus D. Leech wrote:
>   
>> There were a batch of bad PHY chips, and I wonder if yours is one of them.
>>
>> U12, a DP83865 is the Gigabit PHY.   On "bad" versions of this chip,
>> they run
>>   *really hot*.  You could *gingerly* feel yours and see if it's really
>> uncomfortably
>>   hot.  If so, you likely have a bad PHY, in which case, it should be
>> returned.
>>
>> They've been having occasional trouble with this PHY chip, and they pass
>> the checks
>>   but fail sometime later. 
>>   
>>     
>
> Although I did get find_usrps working briefly (by enabling TX pause)  I
> couldn't get any data into usrp2_fft.py.
>
> Repeating the steps I tried earlier just have it fail again. It is,
> however, "forgetting" the tx pause flag - could that be a negotiation thing?
>
> I shall whip the cover off later and do as you suggest from a cold
> start. If its a bad PHY then I shall make arrangements to return the USRP.
>
> Many thanks
>
> Steve
>
>
>

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