Inverted power plug polarity

[danielcbit]

Hi everybody,
Just received my parallella board a few days agora and rushed to get the thing up and running. I read the quick tutorial and some of the documents.

I had a good power adapter laying around, (5V, 2A specs). But the problem was that I didn't noticed until was too late was that the pin polarity was inverted.

So I plugged it on the parallella board and fired up. Just to after realize what I have done. Right after I tried with other power adapter but I had no signs of life from the board. No green led lighten.

I tried to power by USB by plugin to the connector next to the ethernet port and switching the jumper to the right.
The green led lighten up but I had no response from the HDMI nor the Ethernet leds.

So, here are a couple of questions:

1- Did I irreparably damaged my new board?
2- I measured the voltage between the power selector pins and a ground and it gave me 2,26 V approximately. Even using a 5V, 2A Apple Power adapter for iPad. Is this a sign that I damaged the board or for some reason the Apple iPad adapter is not providing enough juice to power the board?

Thanks

[9600]

My guess would be that permanent damage has occurred, but hopefully someone better informed can comment. It certainly doesn't sound promising. If you have a USB UART (3v3 logic levels) you could attach this to the UART header, run up a terminal emulator and see if you get any output.

Regards,

Andrew

[danielcbit]

I tested with yet another power adapter with the correct polarity and this time the green light come up.

I also plugged in a TTL-USB adapter to see U-boot messages, but had no luck so far. Don't know if adapter I have (PL-2303HX based) supports 3.3V signal levels or only 5v.

I tested again the voltage between the jumper for power select and ground and read 2.6V approximately, but the green led was on and both the Epiphany-III and Zynq 7020 started to get very hot.

Is there a way that I can be sure the board's power system is damaged or not?

Thanks!

[9600]

[danielcbit]

Hi 9600

Just a quick update, tested once more the UART output again and could read some things being sent out on the serial interface when I powered up the board, but nothing that makes sense. But at least something came through.

I'll have to get an ammeter to mesure the current yet. But just to be clear, I'll have to test between the barrel connector or the two pins on the jumper and any ground on the board, right?

Thanks!

[9600]

[danielcbit]

Well, I measured the current in the power selector pins and to my surprise I read around 3A. Tested the voltage and got 3.4V. All this using the the 2A, 5V power adapter.

So based on this I can assume this board is dead, right?

[9600]

I'm afraid it certainly sounds that way, as you should be reading around 1A and this explains why the voltage is so low.

Regards,

Andrew

[danielcbit]

Hi.

Recently I gave another try to the board and found some things.

The U36 element (NC7SZ125) was damaged, so the + and - poles of J12 were in short circuit, and this short circuit is probably dragging down the 3.3 voltage in 3P3V (is around 2.4V when powered through USB).

Can some one explain what is the function of U36? Can I power on the board without it, through USB?


Thanks!