More fault finding on Banggood's £15 oscilloscope - I'm now 99% convinced it's the LCD that's failed.
http://bit.ly/1RzsbiM DSO138 DIY Digital Oscilloscope Kit Electronic Learning Kit
http://bit.ly/1RzsbiM DSO138 DIY Digital Oscilloscope Kit Electronic Learning Kit
I had this issue, replaced Q2 Transistor (S8550) and its now back to life, good luck all
I saw you looking at the schematic of the DSO, where did you find it? could you link it in the description? I had bought one that behaved like yours that had bad soldering on the LCD ribbon cable, which is between the LCD and its carrier!
Personally I would have started with DC measurements before breaking out the scope.
Get a quality power source and not that toy power bank – good clean power source.
I've had my kit sitting on the shelf since the middle of 2016 and now that I've seen a few videos on it and actually saw you use it is feel confident I can assemble it and upgrade the firmware. it appears the USB connector is not going to be used so I will not install it
Hi Julian, Markus Fuller did a build of a similar scope and was supplied a faulty regulator that lasted all of 10 seconds he replaced it and the scope worked fine. I've not ead through the comments so apologies if my comment as already been put earlier cheers Sean
Mine did that until I bridged the jump points.
I have a similar problem and don't have a scope to trouble shoot it. My LCD lights up but nothing comes up on the screen. I never saw the green LED light up either. My power supply might be the problem so I will try again with a better power supply. I had trouble figuring out where all the resisters go as they didn't mark the values and some of them gave me readings that fluctuated so much that I wasn't able to be 100% sure of each one. I may have to send it back to get a new one if possible. I also ordered the scope with the clear case and they didn't send the case, so I should just send it back.
Banggood's customer support just sucks. If you get a good kit, great. If not, just start a Paypal dispute. They weren't working with me at all when mailing, I started the Paypal dispute, they never answered it and I got my cash back.
Good to know their tech support sux.
Hi Julian, I've just built one of these and, apart from a problem with the probe compensation adjustment on the 1 volt range, it seemed to work straight off. But when I fed it a 1 kHz square wave from my Owon DSO 'scope's prob cal output the DSO138 reported it as 2 kHz! It looks as though there is a clock frequency problem within the system as both the cal output (actually only 500 Hz) and the timebase are both wrong, although they agree with each other. Have you encountered this phenomenon?
I'm watching and waiting to see how the company deals with your fault,which I believe is the LCD as you have done all reasonable tests.I am interested, in buying one as a part of a bigger project, so hope all goes well Julian.
very good videos as usual .
What make is the oscilloscope you used to debug this one?
How did you go Julian? I just got mine working, I had the issue with AV- producing a very low + output and I replaced Q1 as it had blown. I too believe L2 is a problem causing Q1 to overheat.