[DEFECTIVE] Another Dead Latte Panda Alpha (no LEDs)

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User avatar
philgaskin
Posts: 5
Joined: Fri Jan 04, 2019 5:43 pm

Sat Mar 07, 2020 7:55 pm

I've been using my LPA successfully since backing on Kickstarter. However, a week ago, when I tried to power it on, it was completely dead. I tried changing the USB-C power supply and even made a 12v DC power connector as others advised, but I get absolutely nothing - No LEDs at all. Although I've been using it for over a year, it is just used as a small footprint PC runnning Windows10.

My board seems to be in perfect condition with no obviously failed components. I even removed the fan to see if anything was fried, but again nothing obvious.
When using USB-C power, I see 0.5v on the 3.3v pins, 0.7v on the 12v and 0 on the 5v. When I power by 12v DC, I see 12v on the 12v line, 0.5v on the 3.3v and 0v on the 5v.

I'm obviously out of warranty period, but really disappointed that it is dead - my original LattePanda is still going strong after many years. I have reviewed the many post from people who appear to have the same problem and tried all the suggestions without success. It does appear to me that there must be a design fault somewhere for so many to fail with this symptom. I'd welcome ang further suggestions and attach images to show the very good state of the circuit board.
Attachments
IMG_1420.jpg
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IMG_1419.jpg
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User avatar
msrego
Posts: 7
Joined: Sun Nov 24, 2019 4:10 pm

Tue Mar 24, 2020 1:35 am

Hello philgaskin,

From the voltage reading you gave, it is very probable you have a short circuit somewhere in the board, most probably on the 5V rail (due to the 0V readings).

Check the thread I opened and see if the 5V rail is shorted by measuring the resistance across the capacitor I circled in the photo.

User avatar
LattePanda
Site Admin
Posts: 2523
Joined: Wed Jan 20, 2016 9:09 am

Tue Mar 24, 2020 3:16 am

Hi philgaskin, pls help check whether ther is a short circuit on the 15V and 9Vpin.(as attached pic.)
20200324111503.png
20200324111503.png (2.11 MiB) Viewed 2770 times
Enjoy Tinkering with LattePanda ! :lol:

User avatar
philgaskin
Posts: 5
Joined: Fri Jan 04, 2019 5:43 pm

Sat Mar 28, 2020 1:48 pm

msrego wrote:
Tue Mar 24, 2020 1:35 am
Hello philgaskin,

From the voltage reading you gave, it is very probable you have a short circuit somewhere in the board, most probably on the 5V rail (due to the 0V readings).

Check the thread I opened and see if the 5V rail is shorted by measuring the resistance across the capacitor I circled in the photo.
Hi msrego, I'm reading 306 ohms across that capacitor.

User avatar
philgaskin
Posts: 5
Joined: Fri Jan 04, 2019 5:43 pm

Sat Mar 28, 2020 1:50 pm

LattePanda wrote:
Tue Mar 24, 2020 3:16 am
Hi philgaskin, pls help check whether ther is a short circuit on the 15V and 9Vpin.(as attached pic.)
20200324111503.png
Hi LattePanda,
I get zero volts across both of those points (15v and 9v). I tried with both 12v power and the LP USB-C Power adapter.
Any ideas?

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