Lost 5-volt signal from pin 49 on PC-LPM-16

[Tripoli5333]

CUTTING TO THE CHASE
Can you tell me how to check if I accidentally drew more then 1A from pin 49 and if the fuse is now open and, if so, how to replace it?

THE BACKGROUND
Was learning how to use this device to read analog voltages.

Using Visual Basic examples from Component Works and Measurement Studio I typically did the following.

Run various test example programs and then tap wire from pin 49 (5 VDC) to wire from pin 3 (analog input for channel 0) using an NI supplied cable and green terminal screw "breakout box".

This has been working for quite some time (ie. From a graphing standpoint I get no reading then I get a 5 volt reading which is what is to be expected).

This morning it stopped working and usi
ng a volt meter connected to pin 2 (analog gnd) and pin 49 (5 VDC) I noticed 0 volts where I previously have always been able to measure 5 volts. I also checked pins 20 and 21 (as a test) and sure enough read -/+ 12 volts respectively.

The board still appears to function perfectly (using an external 1.5 VDC batter instead of pin 49) when trying to measure an external voltage.

The manual lists pin 49 as:
"This is the 5 volt power supply from the PC bus. The power line has a 1.0 A fuse in series".

I have examined the card and can find no physical damage to it nor any sign of a shunt or other type of fuse open. I cannot even find the fuse on the board.

Can you tell me how to check if I accidentally drew more then 1A from pin 49 and if the fuse is now open and, if so, how to replace it?

Thanks.

PS. Moving forward I will no longer use pin 49 in this way, never should have, but a battery was not handy at the time.

[RIO-Todd]

There is actually a fuse on the DAQ device that you might have blown if you tried to sink too much current from the +5 V pin. The user manual of the LPM-16 and the other document below discuss the fuse.


What Fuse Does My DAQ Board Use?
http://digital.ni.com/public.nsf/websearch/E1F4D5736D91A625862560B6005BF81F?OpenDocument

PC-LPM-16/PnP User Manual
http://digital.ni.com/manuals.nsf/webAdvsearch/2518F44F80540E7B8625665E005D6DBD?OpenDocument&vid=niwc&node=132100_US

[Tripoli5333]

Received the following excellent reply from NI customer service...

It does sound like the fuse was tripped. The fuse used is a self-reseting fuse, so powering down the machine and the powering back up should reset the fuse. The fuse should look like a little green resistor in series with channel 49. You should perform a continuity or resistance test across the fuse to see if it is completely blown (not likely though).

To repair it there are two options. You could send the board to us for repair (it's probably out of warranty though but this is the best repair option). However, from looking at a knowledge base it would appear as though the fuse is a 125V 1A pico fuse made by Littlefuse (part number is 251001). Replacing the fuse yourself would however
void any warranty on the board. I hope that helps. Have a good day.

The fuse turned out to be blown and it was labled F1 on the board.