scxi 1125 R202 getting burned

[richardmass]

Wondering if anyone else has seen this issue.

I have about 200 of these cards (SCXI-1125) in service in production test machines.  Quite a few of the failed units have R202 burned on the SCXI-1125 card.  Sometimes replacing R202 fixes the issue, but more often it does not.  Since i do not have a schematic of the 1125, it is hard for me to tell if this is a design flaw, or if it is something that we are doing.  Luckily, I also have a stack of 32 of these cards that were purchased for a project that was cancelled, so spares is not an issue thankfully. 

[S_Hong]

Hi richardmass,

There has not been any reports of SCXI-1125 modules failing due to the R202 resistor. Unfortunately without any more details on your application, it would be difficult to figure out why this may be causing a problem in your application. 

[richardmass]

We have 4 of these 1125's in a pxi 1010 or 1050 chassis.  The input's come from several different sources all of which are 0-10V DC.  We have the outputs on the back side going into headers with the part number 182671-01 which then are all connected to a board 160405A-01 and then cabled to the from of a PXI6031E card.

We are using CVI 5.5 Teststand 1.03 (yes I know they are old), and Nidaq 6.9.3.

I've also been told that we use special 1125 cards that were design to handle 0-10V.

[S_Hong]

Hi richardmass,

Could you be more specific about the application? Are you simply measuring a static DC voltages? What is generating these voltages?

[richardmass]

We are testing power supplies, specifically DC to DC converters.  So yes, static DC voltages.  We are also reading static DC voltages from the analog controls of some of the other instruments in the rack (power supplies and loads).  At no time is there more than +10V present on any channel.  These being 8 channel devices, I would find it strange that we are only seeing damage to one component.  As far as I know, the way we have it cabled, we are using all 8 channels separately and using the mux in the 6031e card to channel the readings to the AtoD.

So I would like to know the purpose of R202 in the circuit of the SCXI1125?

[tnek]

Hi Richard,

Thanks for letting us know about this problem. Would it be possible for you to call in to discuss this issue? If you would like, you can leave your email here or give permission for me to get your email from the forum administrators. Let me know how you would like to proceed.

Regards,
Kent
Applications Engineer

[richardmass]

You can get my email from the forum admin.  We can go from there.