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Output voltage low (only 1v)
Moderators: adafruit_support_bill, adafruit

Output voltage low (only 1v)

by mrdrako on Mon Feb 25, 2013 10:44 pm

Hi,

First time poster, so be gentle. :)

I just soldered the MB and was testing the output voltage, and I'm getting just above 1v, around 1.18v. I've reviewed everything and it all looks right. Oh, and the batteries are new, and show 3v. I took some photos of the board, will follow the data.

After reading another post, I took some measurements across some of the points, here they are:

D1-D2 = .68v
D1-D3 = .67v
D1-D4 = 1.18v
D2-D3 = 0v
D2-D4 = .45v
D3-D4 = .44v

R1 = .43v
R2 = .66v
R3 = .44v
R4 = .67v

Thanks for looking!
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mrdrako
 
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Re: Output voltage low (only 1v)

by adafruit_support_bill on Tue Feb 26, 2013 6:20 am

The soldering looks very good, but your LT1302 is installed backwards. The notch in the end of the chip should line up with the one on the silkscreen.
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Re: Output voltage low (only 1v)

by mrdrako on Tue Feb 26, 2013 7:31 am

The soldering looks very good, but your LT1302 is installed backwards. The notch in the end of the chip should line up with the one on the silkscreen.


Son of a ....

Thank you. Rotated the chip and the output voltage is now 4.98v. Will re-solder the socket later today.
mrdrako
 
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Re: Output voltage low (only 1v)

by adafruit_support_bill on Tue Feb 26, 2013 7:41 am

I wouldn't bother changing the socket. It is difficult to remove these without damaging something,
As long as the chip is in the right orientation you should be fine. :D
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Re: Output voltage low (only 1v)

by mrdrako on Tue Feb 26, 2013 9:25 am

I did it anyway, and it was a pain in the a$$. :D But I'd rather have it right in case something makes me question it later.

One last question: with new batteries, the output voltage was just shy of 5v (4.98) but the build tutorial stated it should be just over. Now, it did trigger charging in the phone, and I watched the phone go up one percent, so I guess it is working correctly. Is this within normal tolerances, any reason to be concerned?

Thanks!
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Re: Output voltage low (only 1v)

by adafruit_support_bill on Tue Feb 26, 2013 9:36 am

4.98v is well within the norm. That is off by only 0.4%.
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