White screen, heating U5 and short circuit 3.3v - GND

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JoTom
Posts: 2
Joined: Mon Apr 04, 2016 11:34 am

White screen, heating U5 and short circuit 3.3v - GND

Post by JoTom »

The kit is genuine, already received confirmation, but is defective. It has an almost short circuit between 3.3 V and GND ( resistance 19 ohms ), between GND and BTN1 (pin 28 PB15 MCU) ( resistance 1.7 ohms ) and between GND and BTN2 (pin 27 PB14 MCU) ( resistance 1.7 ohm ). The result is white screen, heating U5, the LED does not blink, incorrect voltages and non functioning of the kit. When open the JP4 U5 no longer heats up and the voltages are different but equally incorrect. Can only be a short circuit in the MCU or on the PCB tracks.

The voltage values at TP20,TP21 and TP22 with and without JP4 and L3 are:
L3 and J4, both removed:
TP20 = 9.15 v
TP21= 5.05 v
TP22 = 3.29 v
LED off
Only L3 removed:
TP20 = 8.31 v
TP21= 1.95 v
TP22 = 1.09 v
LED off
Only JP4 removed:
TP20 = 8.66 v
TP21= 5.04 v
TP22 = 3.29 v
LED off
Both L3 and JP4 present
TP20 = 8.29 v
TP21= 1.93 v
TP22 = 1.07 v
LED off
I would appreciate some help.
michalism
Posts: 10
Joined: Sat Apr 09, 2016 9:16 am

Re: White screen, heating U5 and short circuit 3.3v - GND

Post by michalism »

Hi.

it seems we have the same problem. For sure there's a short in my case.
Even removing caps and a couple of switches I still get a short between 3.3 and GND. I have run out of ideas and I am waiting for Jye people to provide some directions. you may want to follow my post too just in case. http://www.jyetech.com/forum/viewtopic.php?f=18&t=799.
My kit is the one with the SMD components pre-soldered.
michalism
Posts: 10
Joined: Sat Apr 09, 2016 9:16 am

Re: White screen, heating U5 and short circuit 3.3v - GND

Post by michalism »

Hi.

have you been able to solve your problem?
JoTom
Posts: 2
Joined: Mon Apr 04, 2016 11:34 am

Re: White screen, heating U5 and short circuit 3.3v - GND

Post by JoTom »

Hi.

I could not even solve the problem.

Thank you
michalism
Posts: 10
Joined: Sat Apr 09, 2016 9:16 am

Re: White screen, heating U5 and short circuit 3.3v - GND

Post by michalism »

not sure if it is related, but your problem seems similar to mine.
in my post http://www.jyetech.com/forum/viewtopic.php?f=18&t=799 Jye suggests that there may be a short to ground on one of the 3.3 pins on the board. You may want to check last post in my thread for more details.
I did not have time to check their suggestion, but hopefully I will in the next couple of days...
just in case this help you...
michalism
Posts: 10
Joined: Sat Apr 09, 2016 9:16 am

Re: White screen, heating U5 and short circuit 3.3v - GND

Post by michalism »

Hello

did you manage to solve your problem?
It turns out my mcu is shorted so I need a replacement. :(
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