How to repair a FeelTech FY3200S waveform generator?

[EnricoTanz]

Hi all, im a new user! I've been following this forum for some months, looking for a good oscilloscope. I've found it

I also bought a FeelTech FY3200S waveform generator, it was very cheap, and it came from China.
It worked fine, until i connected it to my pc.
I installed the drivers and the softwares properly, following the instructions on its cd.
Suddenly, as last step, i connected it to my pc via usb, and i turned it on and...



It stopped working! The software can't find it, and it always shows black squares in its display. Also when i disconnect it from my pc.
I think it's gone, but hopes are always alive.
The seller sent me a refund, but I don't need to ship it back, so.. I don't want to throw it in the trash...

I've looked everywhere for a ''factory restart'' keys combination, but I found nothing.

Do you have any idea?

Thank you.


...And sorry for the bad english 

[TheoB]

Open it up and measure the power supplies. Check the crystal oscillator. Since it worked for a while it could also be a bad solder joint or connector. The basic fault finding procedures 
You might also have killed it when you connected the USB cable to your PC while powered on. The signal generator is known to have a large powersupply leakage when you don't ground it first.