Author Topic: no power to the PiCap?  (Read 2254 times)

Offline Ken

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no power to the PiCap?
« on: February 11, 2017, 01:19:24 PM »
I hooked up power to the PiCap but the green led is not coming on.  So far I've validated that I'm getting 12v at the PiCap power connector and none of the fuses are blown.  I've got the Pi powered by the 5v power supply because it wouldn't power on using the power from the PiCap.  I'm also getting 12v out the PiCap GPIO 18 & 19 connections.  The jumper for powering the Pi has been removed and I've got pins 1&2 and 3&4 jumpered.

What should I check next?

Offline bpos

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Re: no power to the PiCap?
« Reply #1 on: February 11, 2017, 03:40:12 PM »
Dumb question but do you have the V and the Gnd to the correct pins on the PiCap? There should be 3 jumpers installed on the Pwr select for 12vdc.  Is this the the first time you are using this device? (has it worked in the past?)

Offline David Pitts

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Re: no power to the PiCap?
« Reply #2 on: February 11, 2017, 04:33:18 PM »
The PI should never have 12V on the GPIO pins that seems suspect. The led should light though on the PiCap.
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Offline David Pitts

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Re: no power to the PiCap?
« Reply #3 on: February 11, 2017, 04:41:24 PM »
Please post a  good pick of the board. Maybe something will stand out.

Offline Ken

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Re: no power to the PiCap?
« Reply #4 on: February 11, 2017, 05:48:14 PM »
Here's a picture of the board connected to the Pi.  Before hooking up any connections I double checked the polarity and output of the power supply with my multimeter so I know those are correct.  When I said I was measuring 12v on GPIO 18 & 19 I actually meant on the V and Gnd connections of P1 and P2.  As far as I can tell the Pi is working properly.  FPP loads without any errors other than the audio driver which I assume is normal because the PiCap is attached and I was able to go in and add the PiCapp to the configuration.

Let me know if you need any additional information.
 

Offline David Pitts

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Re: no power to the PiCap?
« Reply #5 on: February 11, 2017, 06:19:51 PM »
Hard to tell, but "D1" looks like it is not soldered on one side. Maybe it is on the other side.

Offline bpos

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Re: no power to the PiCap?
« Reply #6 on: February 11, 2017, 06:30:00 PM »
David is definitely the man with the plan. I have some things you might look at as well.

Physically the board looks good. The IC next to the battery looks like it could be re seated? Probably doubtful. David is the IC on the regulator polarized?  Mine shows the dot lower compared to his upper?

On the wiring setup.. how about unplugging the strand of lights all together and re installing the PI power jumper and try that?   I have all my jumpers on DMX but shouldn't make any diff there.  The 2a fuse is good? No GPIO pins bent or broke on installation?

Have you used the board before?

Offline Ken

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Re: no power to the PiCap?
« Reply #7 on: February 11, 2017, 06:48:51 PM »
Here's a picture of the bottom of the PiCap.  From there it looks like both sides of D1 are soldered.  Also, I have tried hooking everything up without any lights and I get the same thing.  I also just tried running "sudo hwclock -r" on the Pi and it said it couldn't find the clock. 



Offline Ken

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Re: no power to the PiCap?
« Reply #8 on: February 11, 2017, 06:57:42 PM »
I just measured the voltage across the 2 amp fuse and it's only showing 16 mv.  Shouldn't that be 5v?



Offline David Pitts

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Re: no power to the PiCap?
« Reply #9 on: February 11, 2017, 07:06:17 PM »
Yeah. You should. Could be the regulator. Send it to me I can fix it.


Offline Ken

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Re: no power to the PiCap?
« Reply #10 on: February 11, 2017, 07:26:18 PM »
Ok.  I'll ship it out Monday morning to the Peyton, CO address that was on the box it came in. 

I know it's not your fault but I'm so bummed right now.  I just got it from you on Wed so I was really looking forward to playing with it this weekend.  Oh well!  Life happens.

 :'(

Offline David Pitts

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Re: no power to the PiCap?
« Reply #11 on: February 11, 2017, 07:38:40 PM »
Sorry. First one that has had problems that I know of. Well we will get it fixed-up.

Offline Ken

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Re: no power to the PiCap?
« Reply #12 on: February 11, 2017, 07:45:55 PM »
Sometimes being the fist one isn't always a good thing.  lol

Like I said, no worries.  Life happens.

Offline pixelpuppy

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Re: no power to the PiCap?
« Reply #13 on: February 14, 2017, 07:34:44 AM »

I just measured the voltage across the 2 amp fuse and it's only showing 16 mv.  Shouldn't that be 5v?

I'm sure David will get your board fixed up.  But...

When you say you measured voltage "across the fuse", it sounds like putting your probes on both sides of the fuse and measuring.  That would be measuring voltage DROP across the fuse and in that case 15mV is probably correct.

To measure voltage "at the fuse", you will need to keep the negative probe on the negative power supply input terminal and then test the positive probe first on the input side of the fuse and then on the output side of the fuse, still keeping the negative probe on the negative power supply input at all times.

Perhaps that is what you did, but the way you worded it sounds like you were measuring across the fuse so I just wanted to verify which way you were measuring.
-Mark

Offline Ken

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Re: no power to the PiCap?
« Reply #14 on: February 14, 2017, 03:25:38 PM »
It was a poor choice of wording on my part.  I tested it just as you described. 

 

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