xM not powering on, overvoltage LED (D13) always on

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1

I'm having some power issues with my xM. When using three different
5v DC supplies that worked with my C3 Beagleboard, the overvoltage LED
comes on and the board does nothing. When powered off of the USB OTG
port, the board will power on but D13 still turns on (and also the USB
hub will not power on).

Also, page 46 in the documentation states that D16 is the overvoltage
LED, but elsewhere in the documentation, and on the board itself, it
is labeled as D13.

2

This means that the voltage is too high. It is designed to shutdown to protect the board. The Rev C board has no such circuit. So that fact that it powers up OK on a Rev C3 means nothing. It can also be caused by improper system grounding. You need to make sure that all components in the system connect to the exact same grounds and that the power supplies you use are grounded and not isolated…

Gerald

3

I found the issue. The board powered on successfully for a moment
when I flexed the board slightly while pulling out a cable. I looked
at the board carefully with a magnifying glass and found that U19
isn't sitting properly. Pressing it slightly makes the board power
on. Image of the problem: http://i.imgur.com/g8ZUN.jpg

I'll just resolder it.

Nirav

4

Well that stinks! Glad you got it working. I will ping the manufacturing folks and give them a black eye!

Gerald

5

Hope these are only isolated issues with the manufacturing, but mine (xM) has the U15 firt pin unsoldered, Im currently revieweing the schemantics to see if this is how its supposed to be

And the beagleboard toys vga that im using has a similar issue (same manufacturer), there is no display at all on the 10 minutes on first start of the day, then after the vga board is somewhat warmer it is easier to bend it, and then the display comes (you need to keep it bent with pressure on the place where the standoff is to have the display working), but there is no visually indications of where the issue might be (the header and its pins are correct)

I would be ok with all of that, but the bad part is that after the display starts to work, the image is very washed out, like gamma 3.0 or more

Lioric

6

Please send me a high resolution picture and I will check into it.

Gerald

7

U18 and U5 are supposed to have unsoldered pins on them. Please check the reference designator and make sure you have the correct chip.

Gerald

8

Thanks Gerald, it should be ok then, as the xM works correctly

Now we need to identify the issue with the bbt vga board, but it mostly seems to be a manufacturing issue

Lioric

9

It could be a silicon issue. If it works after it heats up, there may be an issue with one of the parts on the board or as you say, it coul deb a solder issue, although that board does not generate that much heat. I suggest you ping the Beagleboardtoys folks and get an RMA.

Gerald