another overvoltage

[ziopiffi]

Hello
  I was given a dso150, I tested the main board and it worked properly but I have seen with regret that the tension of my power supply was 16 volts ... I soldered the switches and now I have 3.3 volts in short, without mounting the analog card ... I have changed the 1117 but without success .... the screen works but it's white, not load programs ..... how can I know what I fried ??????? now the power is 8.48 volts.
thank you for your answer and have a nice day. Piffi

[jye1]

Did you see the LED (D1) at back of PCB blinked when power was applied? If it did that indicate the MCU is good.

[ziopiffi]

[ziopiffi]

Did you see the LED (D1) at back of PCB blinked when power was applied? If it did that indicate the MCU is good.

Hi, thanks for your reply, I have unfortunately not the LED flashing. the power supply is short-circuited, i'll try to desolder the 3.3 volts of MCU and see if the short disappears, but if MCU is burnt because it is short-circuited? if the MCU has burned the LED does not work but should not be shorted ........ just it does not work ...... I'm wrong? it is possible that the MCU is in protection? what is the behavior of the MCU in protection? how can I reset it ??
Thank you and have nice day
I'm sorry for English using google translator

[ziopiffi]

not one idea????

[jye1]

If the MCU was burnt it could be shorted inside. The MCU does not have protection mode. Removing the chip can verify if you have tools and skill.

[ziopiffi]

Thanks for the reply. Do you think my idea about desoldering the first pin could have stopped the short-circuit in the power supply?
Thank you and have a nice day.
Wrote with the help of son-translator

[jye1]

I'm not quite sure. I'd say usually not if there is internal shorts.

[ziopiffi]

ok....i can change mcu but i can't program it........solution???
thank you ...and nice day for you.
Piffi

[jye1]

Please see how to program the MCU http://www.jyetech.com/Products/LcdScop ... rmware.pdf .