03-08-2011 05:37 PM
Our ML402 evaluation platform with Virtex-4 (5V power supply) was briefly plugged into a 19V power supply, and is probably fried, as the power light is flashing, indicating an overload condition. There are three power regulators on the board, all of which are probably damaged.
Any advice about repairs, or is it hopeless?
03-08-2011 06:07 PM
Since probably no circuits on the board use the 5V input directly, it's likely that only
the power supplies themselves were damaged. If you can replace them it's
probably worth a shot.
03-08-2011 06:53 PM - edited 03-08-2011 07:18 PM
There's quite a bit connected directly to the VCC5 input rail on the ML40x board schematics.
I would suggest connecting a bench power supply to the 5V input connector, slowly dialing up the current limit control from 0 (current limit) to around 3A or so. See if the supply voltage will run up to 5V, or if current limit holds the output voltage to some lower level.
If the supply stays current limited (at 3A) below 5V output, the odds are good that some device(s) (including decoupling caps which may not be rated for 19V) has shorted to GND. Any such shorted devices should be getting warm -- VERY warm. Using the 'hot thumb' test (or the rising plume of smoke test), one by one remove the shorted items from the board.
With all the shorted items discovered and removed, what will be left are:
You will simply have to work through the board, one component at a time.
If your time has some value (greater than zero), or you cannot afford to invest further development effort with a suspect compromised board, then this is your chance to
Hope this helps...
-- Bob Elkind
03-10-2011 12:15 AM
Thanks very much. I will run through the suggested tests and hope that not many components are at fault. Otherwise it looks like it's time for an upgrade...
03-10-2011 08:35 AM
Since the board failure is due to wrong power. So I am sorry to say that there is no possibility to get board replacement from XILINX.
If regulators failed immediately after wrong power you are lucky. Because they will acts as bowled fuses and protect remaining part of the circuit.
The below are some suggested steps to debug your board
Some third party servicing stations might available locally. If the Power adapter is not same which is supplied with Board it is always safe to measure voltage before connecting to the board.
03-10-2011 09:12 AM
If the Power adapter is not same which is supplied with Board it is always safe to measure voltage before connecting to the board.
Now you tell him!
-- Bob Elkind