Arty Z7-020 regulator failure?

[lrodgers]

Just had an Arty Z7-020 come in today. I was running it off the power brick from Digilent for about 10 minutes, when I came back and found that the board no longer had power. The brick measured at 12.12 volts, and re-jumpering it to USB power allowed it to come back to life. I checked the schematic, and found that the +5 output from the regulator goes to the right-most pin on the USB/regulator select jumper, so I measured it. 0V.

I also noticed a large amount of heat from that area, not sure if it's normal or just the result of a failed regulator.

[jpeyron]

Hi @lrodgers,

I'm sorry to hear you are having issues while trying to power the board externally. Before we move forward with the RMA process,could you please measure C192 while using the external powering.

thank you,

[lrodgers]

Sure, can you tell me where C192 is? The capacitors don't seem to be labeled on this board.

[jpeyron]

Hi @lrodgers,

It will be close to IC24 the Step-Down Converter on the top of the board to the right of the power jack. If it is not labeled I will find it specifically tomorrow when I am in the office and can look at my board.

thank you,

Jon

[lrodgers]

OK, I see three SMD caps nearby.

One is extremely small (couldn't easily reach it with my probes without shorting it, so I didn't try) and placed horizontally right above IC24. 

The next one is below IC24 and is horizontally oriented. I see 12.12V here, same as the power source.

The final one is to the right of that cap, and is vertically oriented. 0 volts.

[jpeyron]

Hi @lrodgers,

Looking closer at the power brick it can not provide the current needed to power the Arty-Z7-20 as described in the reference manual in section 1 Power Supplies here. The usb 2 provides 500 mA's which is enough current to run some designs on the Arty-Z7-20. If you look at the sales page for the power brick the 12v can supply +-100mA as described here.  Please try running the Arty-Z7-20 externally with a wall wart that provides more current some thing like 1-3 A's.

thank you,

Jon

[lrodgers]

This is the wall wart I ordered with it and was using: https://store.digilentinc.com/12v-3a-power-supply/

It's 12V 3A, so I'd think it'd be fine?

 

I looked at the schematic and discovered that I could remove the USB/REG jumper and power the board through the Arduino shield header's +5V line, from a bench PSU. This works and lets me run designs that need more power than USB provides

[lrodgers]

Is there any way I can order another Arty Z7-20 and return this one with the regulator fault for a refund after I receive the other one? I'd like one where I can actually use the 12V 3A wall wart, but I'd rather not be without it while I work on this project.

[JColvin]

Hello @lrodgers,

I have sent you a PM about this.

Thanks,
JColvin