test impedance

[stoneyys]

Dear SIR

We bought digilent AD3 to test cable impedance at work, 

but now when we measure cable, it seem it dont work normally, 

so we test resistor at first, we put 4.7kohm between +1 and +2, but the result isn't 4.7kohm, please see the attach file

Does the AD3 is broken? and how do we have a repaire by you?

thanks

 

[attila]

Hi @stoneyys

Select Adapter

 

It looks like you have removed the socket. Make sure there is a connection between the following points, the trace is not broken by removal. The ones on the AD/MTE side are the sense and the other ones the current contacts.

[stoneyys]

Dir attila,

thank your reply,

below is our testing,

After selecting ADAPTER, and connect two place with wire, it can’t work,

Fig1,

Fig2

 

But when I replace small board to demoboard(put component as small board, and put 1kohm on demoboard),

it can measure resistor and capacitor(put 47nF, and 10kohm),

 

Fig3-1,

Fig3-2,

Fig3-3,

Fig4,

Fig5

 

So it seem there is problem in small board,

and I measure this red part on small board(schematic is from digilent website),

they are always 0 when I change resistor(as fig7),

so I think that the relay on small board can’t control the path,  

Is it possible to fix it?

Fig 6

Fig7

 

thanks

stone

Edited August 8 by stoneyys

[attila]

Hi @stoneyys

Are the relays clicking on the adapter when the reference Resistor is changed 100R, 1k,...1M ?
If not, the relay driver ICs may got damaged during rework, since each adapter is tested.
Here you can find the schematic: https://digilent.com/reference/_media/reference/test-and-measurement/analog_discovery_impedance_analyzer_sch.pdf

[stoneyys]

Dir attila,

thank your reply,

after we remelt the connection of this red part GND, it work~

AD3 can measure resistor and capacitor again(put 100ohm, and 1uF), maybe there is tin dross on pin, 

thanks,

stone