Yeah, I dont think these devices should be reaching such high temps. I find it interesting that its the backlight display circuits would generate heat. Do you typically have an LCD connected? I wonder if the LCD needs to be connected in order for the system to operate normally. Without C7 on my board, I will most likely not be able to power up my system to experiment.

--- On Fri, 5/22/09, Bob-322 <rpstevens@gmail.com> wrote:

From: Bob-322 <rpstevens@gmail.com>
Subject: Re: [Gumstix-users] Powering up overo water + palo43 board
To: gumstix-users@lists.sourceforge.net
Date: Friday, May 22, 2009, 7:31 PM


The Palo 43 problems I'm having are similar to yours. The Overo Air fails to
boot properly unless my power supply can output 5v @ 1000mA. The U11 gets
extremely hot quickly, and has slightly discolored the surrounding pcb.
U11 appears to be the adjustable power supply for the LED backlight on the
Samsung display.
Unlike yours, my Palo 43 Rev 2297 does have C7 installed... which also gets
very hot.

Maybe there is a common problem with this circuit on some of the Palo 43
boards?
Other functions that I've used on the Palo 43 like USB Console and Audio Out
are working as expected.




Anthony O wrote:
>
> Thanks for your input R.P.
>  
> I removed the Overo board from Palo 43, plugged in power and checked the
> following voltages: VBATT= ~2V; VCC_1.8= 0 & VCC_3.3=0. I verified that
> the power adapter is supplying ~5V. I noticed that C7 on my board is
> missing. C7 is a 0.47uf/50V capacitor located on page 9, U11-2 in the Palo
> 43 schematics.There is no DNI for C7 on the schematic, so I assume that it
> is missing on my board.  I also notice that U11 gets hot rather quickly
> when power is applied, so I never leave the power adaptor plugged in for
> too long. 
>
> Could this missing cap be the root cause of my power problem?  If it is,
> how shall I proceed with getting if fixed?
>  
> -anthony
>
> --- On Fri, 5/22/09, R. P. McMurphy <loginreg@gmail.com> wrote:
>
>
> From: R. P. McMurphy <loginreg@gmail.com>
> Subject: Re: [Gumstix-users] Powering up overo water + palo43 board
> To: "General mailing list for gumstix users."
> <gumstix-users@lists.sourceforge.net>
> Date: Friday, May 22, 2009, 1:11 PM
>
>
> The green LED on the Overo is connected to the power supply input
> coming from the Palo board 3.3V regulator. So if that LED is off then
> the Overo board has no power input.
>
> As for the reason why is a different matter. Check the 5V supply
> output current to see if it is shutting down due to over current / low
> voltage. Try to power the Palo board without the Overo plugged in and
> see if the 3.3V is still shutting down.
>
> On 5/23/09, Anthony O <anthony_tunde@yahoo.com> wrote:
>> First attempt at powering up Overo water + Palo43 combo. I plugged in usb
>> cable, from pc to palo43 console port, I see LED light up next to it.
>> When I
>> plug in DC power next, I see LED on Overo board flicker for a sec.and
>> stay
>> off. No activity on the console. I assume the LED (D2) on the Overo is
>> the
>> power indicator, in which case I am wondering why it flickers. It
>> flickers
>> and stays off every time I plug in the DC power supply - I use a 5V
>> adaptor
>> which I purchased from Gumstix; no LCD connected to palo43.
>>
>> I could not find a similar case on the mailing list, so I wonder if this
>> is
>> an isolated incident. In any case, what could possibly be happening with
>> the
>> power? I welcome suggestions regarding steps to try, what to look for
>> etc...
>>
>> --anthony
>>
>>
>>
>
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