Hello,
Ive had my DSO 138 for about 6 months now and from one use to the next the test ring signal started showing a 1.7V sawtooth signal
and my trace started drifting from the center line. My power Supply is a 7.6v Lithium Ion battery hooked up to a step up voltage converter set to 12V.
Ive had the same set up for several months now without issue until my latest use. Ive gone through all the voltage checks but at this point I cant Determine the cause