DSO138 Digital Oscilloscope not turning on

Thread Starter


Joined Mar 13, 2023

If anyone has knownlegde about the DSO138, help would be much appreciated!

My problem is that it wont turn on. It's presoldered, so it's right out of the box. When i apply my 9V DC power supply it's just black screen, nothing happends. The thing is that this is the second one i receive from the company i ordered from. The first one also did not turn on. I tried 3 different supplies, all 9V but one with 150mA one with 200mA and one with 400mA. The supplier doesn't know anything about it and cant help. Am i doing something wrong? because as far as i can tell from tutorials and things i read, it's suppose to turn on when applied with a power supply.


Thread Starter


Joined Mar 13, 2023
Thanks for the replies. Polarity is correct. I have not measured voltages, but i'll try and find a 12V instead of a 9V and see if it works. 9V battery didn't work..


Joined Oct 2, 2009
Try the 9V supply again.
Measure the voltage output when not plugged into the DSO138.
Measure the voltage with DSO138 plugged in.
Measure voltages at all regulators.


Joined Jul 10, 2017
When using a battery, if it can not supply enough voltage, the screen will light up but the processor will not run.
When you connect a supply, does the screen light up white? Do you see anything at all?


Joined Sep 21, 2010
Just checked mine & @ 9V it draws 200Ma. If the voltage drops to 8V the processor doesnt work. Check you actualy have 9V at the unit.