This one isn't for a beginner. I ordered the
DSO138 from Amazon the reviews were stellar I thought it would make a good blog post series. Took quite awhile to put together but I "got'er done". The silkscreen could have been a bit more helpful, but all of the SMD parts were already done. Also this requires a 9V power supply. Easy to find on Amazon, but letting you know, it's not included. The other big gripe I have in putting it together, is... the incorrect resistor values. There were a few I had to guess at. Once it was all together, I booted it up, and ... nothing. reading the troubleshooting secton, I needed to short J-something or other. After that is done, I boot it up and lo and behold its running. I hooked it up to it's calibration waveform and let it sit there. Ran like a champ for several hours, then locked up to a white screen. Now it may stay active for up to a minute before switching to the white screen of death. I've set it aside for now, but I may try troubleshooting it sometime to see if I can get it working. All in all, when it was working it was a pretty good little scope. I didn't look at the input impedance or anything like that (because it locks up too fast) but it's easily hackable, and it would be simple match that back to 50ohms with a few cleverly placed components. So yes it's fun to put together, and yes it's a decent scope, but mine quit on me after awhile. Oh and be careful and make sure you keep the 7805 and the 7809 differentiated. I narrowly
missed that calamity.
