[hpsdr] Excalibur checkout

[Chris Smith]

Graham

Many thanks. I was aware that this was only a test for shorts but was a little worried that the high reading might mean an open-ciruit path somewhere. I guess the only way is to power Excalibur up and see if the voltages at the test points are as advertised.

My main concern was that, during population of the board, I managed to get a solder bridge between pins 1 & 2 of the 3V3 regulator. Not having any solder wick or spare clean coax braid, I spent a while applying heat to the tiny chip and was worried that I'd destroyed it - hence the high reading. :-)

Cheers

Chris
G4NUX

On 17 Mar 2010, at 21:47, Graham / KE9H wrote:

> Chris:
> You are OK to power up. You are only looking for shorts.
> Different Ohm-meters will give Ohm different values, based on the
> voltage it is using.
> --- Graham
> 
> ==
> 
> Chris Smith wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
>> 
>> OK. Next problem. I finished Excalibur this morning after winding the toroid.
>> 
>> Then, following the "Checkout prior to first power application",  I checked the DC resistances from the 3 voltage TPs.
>> 
>> +6V was just about spot on at 2.5K to ground and +3.3V was close at 104K to ground BUT +5V to ground reads 14.4K to ground - more than 3 times what the manual suggests.
>> 
>> Should I be worried? I haven't yet applied power as I've had to work for my living today but was hoping to plug Excalibur into the Atlas back-plane tomorrow.
>> 
>> What have others found at this check? Any thoughts would be appreciated.
>> 
>> Cheers
>> 
>> Chris
>> G4NUX
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