[hpsdr] Troubleshooting/repair assistance sought for Mercury card

[Jim Sanford]

All:

I have come to the conclusion that my friend's Mercury card has hardware 
issues.  I wonder if anyone on this list can/will do 
troubleshooting/repair or knows anyone who can.


_Symptoms_:

When first powered up, Mercury seems to work fine, but after a few 
minutes, quits working and the relay chatters in sync with some of the 
"atypical" LED behavior.

Slow motion imaging tells us that U-15, a 3.3-volt regulator which goes 
to a lot of different places on the board, is shutting down, in sync 
with the relay chatter.  (The LED goes OUT.)

Thermal imaging tells us that U-15 is getting quite hot, suggesting it 
is shutting down on thermal overload, not over-current.  It gets hotter 
than U-15 on /either /of my two boards which work.

Thermal imaging tells us that the FPGA is much hotter than /either /of 
my two Mercury boards.

My Mercury board works in the backplane where his does not.  His acts up 
in two different Atlas backplanes.  The two Atlas boards have different 
12-volt and ATX power supplies.


_Additional information:_

We have tried loading earlier versions of Mercury firmware and reloading 
latest version of firmware to see if there were some issue there.  Only 
change is the length of time before the problem starts.

Penelope and Excalibur appear to work fine in his Atlas backplane.

_
_

_Hypotheses:_

This is a Mercury issue, not an Atlas or power supply issue.

There is /something/ going on in the FPGA.

The higher temperature than on two other working boards for U-15 
suggests that U-15 is not prematurely shutting down.


_Request__:_

Is there anyone around who can troubleshoot, or just replace the FPGA?  
I've looked through magnifiers; my eyes are no way good enough to 
replace the FPGA.  I could do the regulator, but as above, the data 
suggests it is behaving as it should.


Thanks & 73,

Jim

wb4gcs at amsat.org




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