J15 Jumper and USB Power Not Working

Hardware related problems and workarounds

J15 Jumper and USB Power Not Working

Postby midnightconman » Fri Aug 01, 2014 8:58 pm

I recently purchased two orders of 18 core parallella boards, one order of 2 boards and one of 6 boards. I planned to connect these using a jumper for J15 and then powering two stacks of 4 boards each. I managed to get 7 of the 8 boards working, but the last board even after jumping shows infinite resistance between the negative and positive power pads. I also tried to power the board via a 2A micro USB cable and I wasn't able to get the power LED to light. I unfortunately do not have a barrel connector in 5V anywhere near 2A. I noticed that the barrel connector leg (when looking at the barrel connector head on) on the right side of the barrel shows a complete circuit with the negative power pad. I just purchased a barrel connector power supply and should have it Tuesday... but if that works I was planning to just drop a bead of solder between the right leg of the barrel connector and the positive power pad, what do you guys think? Can I have someone confirm that the right leg is the positive leg?

EDIT:

Looks like I posted this too soon, I found that you need to switch the power source jumper from the first position to the second to allow for USB powering... so I will try this and see if that does the trick for the USB power issue.
midnightconman
 
Posts: 3
Joined: Fri Aug 01, 2014 8:32 pm

Re: J15 Jumper and USB Power Not Working

Postby aolofsson » Sun Aug 03, 2014 5:05 pm

Hard to comment regarding "the right leg", not sure what that means. Let us know how it goes.
Thanks,
Andreas
User avatar
aolofsson
 
Posts: 1005
Joined: Tue Dec 11, 2012 6:59 pm
Location: Lexington, Massachusetts,USA

Re: J15 Jumper and USB Power Not Working

Postby midnightconman » Sun Aug 03, 2014 6:25 pm

I tried powering the unit via a 2A USB connection as well, with the power source jumper in positions 1 and 2, and unfortunately the power led is not lighting. I will try the barrel connector when I receive it.
midnightconman
 
Posts: 3
Joined: Fri Aug 01, 2014 8:32 pm

Re: J15 Jumper and USB Power Not Working

Postby midnightconman » Thu Aug 07, 2014 2:31 pm

Got the barrel connector power supply last night and tried to power the board, but no luck. Any ideas as to what I can try next, or is it possible this board is dead?
midnightconman
 
Posts: 3
Joined: Fri Aug 01, 2014 8:32 pm

Re: J15 Jumper and USB Power Not Working

Postby FHuettig » Thu Aug 07, 2014 3:26 pm

Hi Midnight,

midnightconman wrote:I tried powering the unit via a 2A USB connection as well, with the power source jumper in positions 1 and 2, and unfortunately the power led is not lighting. I will try the barrel connector when I receive it.

This might just be a typo and/or the pin numbers may not be obvious, but to use the USB input the jumper must be in position 2-3, away from the barrel jack. Position 1-2, closest to the barrel jack, is for the barrel jack.

midnightconman wrote:I noticed that the barrel connector leg (when looking at the barrel connector head on) on the right side of the barrel shows a complete circuit with the negative power pad. I just purchased a barrel connector power supply and should have it Tuesday... but if that works I was planning to just drop a bead of solder between the right leg of the barrel connector and the positive power pad, what do you guys think? Can I have someone confirm that the right leg is the positive leg?


Looking at the jack head-on (mounting hole is on the right, USB power connector is on the left, the "right leg" is ground, as is the "front leg" underneath the jack. The "rear leg" closest to the 3-pin header is +5V. Don't connect the right leg to power, it should be not just a "complete" circuit but a "short" circuit!

I was guessing you might have a blown fuse F1. With your power supply connected to the barrel jack, can you measure 5V at J14 (the 3-pin power-selection header, check the pin closest to the barrel jack)? If you get 5V at J15 (the 2-pin header right next to the barrel jack) but not at J14 then F1 is open. However, the USB power jack (between the RJ45 and the barrel connector) does not go through the fuse, so you should be able to apply power that way even if the barrel jack does not work as long as the jumper is positioned correctly.
-- Fred -- Hardware Guy --
FHuettig
 
Posts: 142
Joined: Wed Jan 29, 2014 8:30 pm
Location: Lexington, MA, USA


Return to Troubleshooting

Who is online

Users browsing this forum: No registered users and 5 guests

cron