RE: [Discuss-gnuradio] RE: USRP + case = electrical short?? EXPLAINED

[Weber, Michael J. \(US SSA\)]

This thread related to the USRP version 4.2, 10-2-2006. As you point
out, the v3 boards have a smaller heatsink pad.

Best,
Mike 

-----Original Message-----
From: address@hidden
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On Behalf Of Brett Trotter
Sent: Wednesday, March 07, 2007 5:52 AM
To: address@hidden
Subject: [Discuss-gnuradio] RE: USRP + case = electrical short??
EXPLAINED


Out of curiosity, what generation USRP do you have? My Rev 3 board has
quite a lot of clearance on the TX-B side (1/4"ish- not measured)


Weber, Michael J. (US SSA) wrote:
> 
> I have identified the cause of the shorting issue I was experiencing 
> and thought I would share. The bottom-left corner mounting hole of the

> USRP passes very close to the internal heat sink pad for the 3.3V 
> regulator; this pad is at 3.3V due to the regulator design (tab is 
> hot). Some of the green board mask had scraped off when the mounting 
> post for the Side B daughtercards was installed, which brought that 
> mounting post, and by extension the enclosure, to the 3.3V potential. 
> Photos of the board site are at http://www.likesgadgets.com/gr/  When 
> the SMA jumpers connected the ground to the case, a short occurred.

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