5V shortcut issue on PXI 6602

[lemmel1]

I have a brand new PXI-6602 and there seems to be zero voltage on the +5V pin. In order to rule out faults in the cable and the connector box I carefully measured the pin 1 of the output connector. 0V. I don't need the 5V but I wonder if the card might be damaged.

I also have an old PCI-6602 which died after nearly ten years of operation. The self test of this old card gives Error -200020. I have read under http://forums.ni.com/ni/board/message?board.id=40&message.id=4012 that this error code indicates a card damage which can be caused by a shortcut between +5V and GND. I have never used the +5V line and don't plan to do so in future.

Now the new card was packaged with a special warning concerning the same shortcut issue, and I also read the topic "pptc" under ni.com/info. That's why I immediately tried to measure the 5V output. I connected the new card with the old BNC-2121 and measured the 5V-Pin on this connector box: 4.8V. After one hour of operation I measured about 2V. Then I replaced the BNC-2121 by a SCB-68 and measured 0V. Then I unplugged the cable and measured directly Pin 1 the PXI-6602 and received 0V. I plugged in again the BNC-2121 it is still 2V.

What's going on? Is my new card already dying? So far all counters and the DIOs seem to work.

Is it possible that the BNC-2121 has an internal damage? Is it save to use it any longer?

Why does the BNC-2121 shows some voltage on the 5V line while the SCB-68 and the PXI-6602 show 0V on Pin 1?

Where is this self-resetting fuse on the PXI-6602? I couldn't recognize it.

If this fuse is broken, can I still use the card? I urgently need it for the next 7 weeks, so I want to avoid to send it in.

Thanks for help,

Hartmut

[lemmel1]

Some more observations:

The fuse on the PXI-6602 is a traditional fuse and is appearently broken. The resistance between the two pads is several Megaohm. Now I am wondering what has caused the fuse to break.

On the connector box BNC-2121 the pin 35 was damaged and bent to the shielding. According to the manual this pin is either already GND or "reserved", depending on the cable. My cable has the number 183432B-05. It seems unlikely to me that this pin has caused the problems.

The cable and the connector box have been used for many years in this state, connected to the old PCI-6602. The old card still gives the 5V and the power LED on the BNC-2121 shines when connected to the PCI-6602. (It does not when connected to the new PXI-6602.) However, the PCI-6602 doesn't work any more. It is probably equipped with a self-resetting fuse.

If I unplug the BNC-2121 and connect an external 5V power supply to the pins 1 and 36, the power LED shines and I measure a current of 12.5 mA. So the BNC-2121 seems to be ok.

My final questions are:

As I don't need the on-board 5V supply, can I ignore the broken fuse and still use the PXI-6602?

What could have make the fuse to break?

Hartmut