5600 is givng 55dB loss at input

[Dannn]

my 5600 is giving a 55dB loss at input...checked the same input on a spectrum analyzer using a 100 MHz signal at -34dBm, whereas 5600 test panel reads the same at around -90 dBm...reference levels at -20 to -30 dBm....variation at input translates to identitical variation at test panel.......but the loss remains the same...is the device blown due to some reason...havent used any input greater than -10 dBm yet.... or some grounding issue i am unaware of...using the socket ground for PXI chassis...i did feel a slight shock once while connecting the same input through to the 5600...but the input was almost always in the range of -50 dBm.......any NI rep please reply or any other expert opinion......

[Dan_K]

Hello Dannn,

It sounds like your device has been damaged and needs to be sent in for RMA.

One note, National Instruments recommends shutting down your system and ensuring that you are grounded (i.e. wriststrap) before connecting any signals to our RF devices. This prevents static discharge and reduces the chance of damaging your system.

Message Edited by Dan_K on 08-28-2009 06:29 PM

[Phuong Thuy]

I got the same problem when I used NI-5661 to look at the Power Spectrum of my signal (I got about 60dB loss).

However, when I do "Self-test" for the device, it has passed. And I used NI-5671 to generate a sine wave with -20dBm reference level and NI-5661 to look at the signal, I got the signal at about -25 dBm (just few dB loss). All the LEDs are working fine as I transmit and receive the signal.

When I tried to change the Reference level of NI-5661 using Property Node, the attenuation changed accordingly and the noise floor changed, but not the amplitude of the signal.

Could you please give me some advice?

Thank you very much.

Phuong

[chris_amadasun]

Hello Phuong,

A 20dBm different is pretty big, how are you cabling your 5661? Have you tried using different RF cables? When was the last time your device was calibrated?

[Phuong Thuy]

Thanks for your quick response, Christian. I cabled 5661 with the included cables as instructed: PXI 10 MHz I/O to 10 MHz OUT, 10 MHz OUT to CLK IN, OUTPUT to CH 0.

I used different RF cable to connect OUTPUT of RFSG 5610 to INPUT of RFSA 5600. When I used Test Panels and RFSG 5610 to generate a signal and RFSA 5600 to receive the signal, I got NO dB loss if Power level at the RFSG <= -10 dBm, and I got 25 dB loss if Power level at the RFSG >= -5 dBm.

The calibration time of my devices:

PXI 5600:  8/4/2008  (Exp: 8/4/2009)

PXI 5142:  8/7/2008  (Exp: 8/7/2010)

PXI 5610:  12/12/2008  (Exp: 12/12/2009)

PXI 5441:  12/11/2008  (Exp: 12/11/2010)

PXI 4461:  01/13/2009  (Exp: 01/13/2010)

I am not sure if the expired calibration has impacted my test results or the hardware has been damaged. Please give me some advice.

With my real test hooked up, I got up to 60 dB loss.

Thank you very much for your help.

Phuong

[chris_amadasun]

Hello Phuong,

In light of your recent post I recommend that you send the board in for repair, there is probably a damaged component on the board.

You will need to create a service request using the technical support link here

Once you call in an RMA can be set up for your device.

Regards

[Phuong Thuy]

Thanks for your response, Christian. Which boards do you think I should send in for repair? Should I send only the PXI 5600? How much do you think they will charge us for repair? Thanks, Phuong

[chris_amadasun]

Hello Phuong,

I would recommend sending in the entire unit, that way the repair technician can test the entire system. I do not know what the cost of repairs will be but the RMA co-ordinator you contact will be able to tell you the repair costs.

Regards

[Phuong Thuy]

Thanks, Christian. I have another question. I cannot find the Control Pallete in my LabVIEW program any more even though I go to View -> Control Pallete. I restarted LabVIEW, still could not find it. I am using LabVIEW 8.6.1 right now. Thanks, Phuong

[chris_amadasun]

Hello Phuong,

This is a strange situation, which may require you to repair LabVIEW, however you will need to post in the LabVIEW discussion forums, an Engineer more familiar with our software product line will assist you.

Regards