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watmes

Nexys 4 ddr power-led is off and vivado can't read the device

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Hello, i have been using this board for 2 years without a problem, but a few days ago i used a design that utilized pmods. today when i tried to boot up the board it isn't working anymore, the power led is off. I did some diagnosis with a multimeter and figured out that the 1.8V and the 1v outputs work, but the 3.3v output doesn't work (number 6 in the included image). the voltage across the power led is about 0.8v but it is off. what could the problem be ?

n4c.png

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Hi @watmes,

Welcome to the Digilent Forums!

1) Please measure with a DMM the voltage on the capacitor:

     C178 - It should be 5V.

1) I would also try cleaning the power switch while the Nexys 4 DDR unplugged. The contacts on the switch could have some build up and are not getting a good connection. 

     Here is a site that discusses contact cleaner and or compresses air. 

2) Have you tried powering the Nexys 4 DDR externally? 

best regards,

Jon

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38 minutes ago, jpeyron said:

Hi @watmes,

Welcome to the Digilent Forums!

1) Please measure with a DMM the voltage on the capacitor:

     C178 - It should be 5V.

 

1) I would also try cleaning the power switch while the Nexys 4 DDR unplugged. The contacts on the switch could have some build up and are not getting a good connection. 

     Here is a site that discusses contact cleaner and or compresses air. 

2) Have you tried powering the Nexys 4 DDR externally? 

best regards,

Jon

1. I measured the capacitor in the black circle (if that's the correct one), it reads 5.46 V but my multimeter isn't very precise 
2. I actually tried that first, but it didn't fix the problem

3. if you mean by the wall adapter I can't find a 5 V adapter in this shape yet

DSC_1604.JPG

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Hi @watmes,

1) Please measure with a DMM the voltage on the capacitor:

     either C180  - It should be 3.3V.

2) Sorry if my question was confusing. By externally powered I was referring to a 5V power adapter.

3) Are you using a standard USB port or a USB HUB?

best regards,

Jon

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4 minutes ago, jpeyron said:

Hi @watmes,

1) Please measure with a DMM the voltage on the capacitor:

     either C180  - It should be 3.3V.

2) Sorry if my question was confusing. By externally powered I was referring to a 5V power adapter.

best regards,

Jon

 I measured it around C180 and it shows 0V

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Hi @watmes,

Is there any component that is overly hot to the touch? As it stands right now, it sounds like either C180/C179 or IC17 is grounding out.

best regards,

Jon  

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3 minutes ago, jpeyron said:

Hi @watmes,

Is there any component that is overly hot to the touch? As it stands right now, it sounds like either C180/C179 or IC17 is grounding out.

best regards,

Jon  

No, nothing gets hot or even warm, I did some measuring on IC7 and getting 5V at Vin and 1.19V at feedback pin, but I can't determine which pin is the output

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Hi @watmes,

Here is the Datasheet for IC17 ADP2118ACPZ-3.3. On page 6, it describes all of the pins. On page 16, Figure 41 Application Circuit shows an example of how this IC is used. The Figure shows that Vout is a combination of SW 9,10,11 going through the inductor.

best regards,

 

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42 minutes ago, jpeyron said:

Hi @watmes,

Here is the Datasheet for IC17 ADP2118ACPZ-3.3. On page 6, it describes all of the pins. On page 16, Figure 41 Application Circuit shows an example of how this IC is used. The Figure shows that Vout is a combination of SW 9,10,11 going through the inductor.

best regards,

 

I did more measuring with the multimeter and figured out none of the IC17 outputs right (pgood = 0, feedback is getting 0, all the capacitors are 0), if the IC is malfunctioning what can I do ?

Screen Shot 2019-03-20 at 12.20.12 AM.png

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