Just some pointers to anyone having trouble with this handheld LCD scope. I've seen other reports on the web about this model not powering up but no answers. I had one that started to power up intermittenly and then eventually refused to power up at all. It would just make a short chirp beep sometimes when pressing the power button, sometime no beep at all. Long story short, you can get the older service manual here which includes full schematics and board layout.
They have lots of troubleshooting steps for no power up and so forth, but in my case it was a problem with the soldering of the "D-ASIC" chip (D3500). I think this is a BGA type or something very similar.
I fixed it by using the old hot air gun trick. I use a method of putting a tiny piece of 63/37 solder on top of the chip and then aim the gun about 6" away on med-high heat. As soon as the little piece of solder starts getting molten, I quickly move the gun away and apply force down on the chip with the handle of a screwdriver (in this case). I repeated this a few times, then let it cool off and voila! Working perfectly again!