Re: [Discuss-gnuradio] Faulty USRP microprocessor?

[Matt Ettus]

Berndt Josef Wulf wrote:
> G'day,
>
> I haven't made any progress in finding a solution to my problem. A direct 
> email to Matt (Ettus) explaining my predicament didn't receive a reply. It 
> was hoped that the manufacturer of the USRP would provide some after sale 
> techmical support for their products.
>   

Berndt,

I am sorry to have not gotten back to you, but I get over 300 non-spam 
emails per day, many with technical questions, and it can be hard to 
wade through them.  I try to go through the backlog at least once a week.

> The USRP is no longer communicating when it was powered up after being in 
> storage for the past 6 month. As mentioned in my previous email, see below, 
> my suspect is the co-processor that hosts the USB interface, although I can't 
> be sure. Perhaps someone on this list knows a procedure that would lead to an 
> accurate diagnosis.
>   

It sounds like the transceiver circuitry on the FX2 has gone bad, but 
the processor is still running.  This the most common failure mechanism 
we see.  We have static protection diodes on the recent boards, but it 
does not seem to change things.  The best course of action is to replace 
the FX2 chip.  We do not see this failure often, but when it does, it is 
often when used with cheap aftermarket power supplies for the laptop, or 
with a nonstandard USRP power supply.

> At this stage I'm contemplating to replace the processor. What needs to be 
> considered prior to replacing this processor, e.g. does it need to be 
> flashed? I'm also looking for a supplier for this chip.
>   

They do not need to be flashed.  You should be able to get the chip from 
Digikey or any other Cypress dealer.  The exact part number is 
CY7C68013A-100AC.  They are about $15 in small quantities. 

Matt