JYE Tech Forum

Hello,
I have the problem with the white screen and the led is no blink.
I push the Reset, and there is no blink.
I think I have a problem with the oscillo (OSC signal), the voltage is too low.
I have remplaced the Y1, C12 and C13 and there is the same problem.
Here is the schematic with the mesured voltage.





How can I solve that? Thanks

did you plug USB in?

hint I didn't!!

~:"

Hello,
I tryed with the usb not plugged, and with it plugged.
No change, windows don't reconize the DSO (I have read it's normal, the usb is not programmed in the DSO software).

Looks the MCU didn't run. Did you have JP4 closed? If yes did you see LED blinked when you press RESET button?

Yes, of course, JP4 is closed and i have the 3,3V on the pin near the MCU on C18.
Non, the led not blink and is correctly soldered.
I alway have 3,17V on the pin of R28 near the led. And when I press the Reset, there is NO change.

I have the same problem.
I have the problem with the white screen and the led is no blink.
Any ideas?
I bought it from ebay from this saller : tomtop_game

did you plug USB in?

hint I didn't!!

~:"

I found the cause of the white screen and the lack of -5.0v at me.
For me it was L4 100 uH not working properly.
After the change with what i have on hand a foot 9 on STM32F103C8 appeared 3.3v , and DSO138 work.

I hope I've been helpful to someone.
Happy Holidays....

Ok, thanks,
I will check that.

UPDATE:

I mesure the resistance of L1 and L3, it's about 4,5 ohms. The value of L4 is incorrect.
I changed the L4, and it's working good!
Thanks karolev!