Bests & Worsts Reviews from Amazon

In my opinion, this is a typical representative of Chinese technology. It looks legitimate on a paper, but in reality is inferior in design, performance; and with predictably questionable build quality. It resembles early pre-production concept of product, which has long way to go before becoming market worthy; or even worse – exaggerated performance to bolster sales, and in combination with deliberate measures to make sure that consumer will not get more than he paid for in their opinion… As the majority of value priced oscilloscopes, this oscilloscope automatically reduces its sampling rate (and thus accuracy) along with increase of the time scale, instead of giving user discretion over sampling rate settings. In User Manual the manufacturer attempts to lecture with their interpretation of sampling theory as probably a justification of this handicap. And of course, specification of this important limitation is not present in (up to date of this review) advertised Product Data Sheet, neither in any other form and location of specifications. Having no “Eject” functionality programmed into tool’s firmware, it always causes USB drive corruption if drive is “hot” attached and then removed. Initially mistaking this as a defect of one particular unit, and exchanging it with another one (thanks to customer oriented Amazon policy), I was greatly disappointed to learn that new one is acting in the same way. And this model is in production for no less than 3 years. Manufacturer had plenty of time to fix this error. And in a first place, how it managed to remain undetected throughout development, testing, and production quality control… It was impossible to bring signal to reasonable “zero voltage” level (Pic-1a,b) in the 500µV/Div range. And where voltage offset inaccuracy was ranging, and even exceeding 100% of scale division! This offset was floating, and seemingly changing over time. Self calibration did not solve this issue, and in the case of my first oscilloscope, it was constantly degrading over time. This inaccuracy only becomes insignificant at 50mV/Div, and in reality makes this setting as the lowest usable voltage range with acceptable visual accuracy (down to 3%-5%). And which actually, is really bad, even for a bargain priced unit. I was forced to return my replacement unit due to out of the box USB interface malfunction, and inability to make PC connection; as it was determined by technical support. On both scopes the probes’ voltage offset control function was acting identically with vertical signal position, making it completely useless and raising even more concerns about tool’s accuracy. Other bad surprises were waiting in a form of software notifications, informing that certain functions which were expected to work, are not available under certain, and apparently most useful settings. And these limitations were not disclosed in specification. Two most notable functions are listed below. Officially, this is a storage oscilloscope with loudly advertised deep sampling memory. But in reality its storage functionality is almost useless. The scope does not record waveforms into its internal memory. The external (corruptible though…) USB memory shall be used, but the waveforms cannot be played back in the oscilloscope… The only “History” waveform data can be played back in the oscilloscope. History recording is only available in “Normal” acquisition mode, and is not available in “Average” acquisition setting (It is also unavailable every other Wednesday of each odd week of the month… Please forgive me this sarcastic joke). Important to mention, that History is rather automatic loop data recorder without user ability to control what and when to record. It neither allows saving, or export recorded waveforms. Widely advertised as a competitive advantage, color waveform grading is not available in Average data acquisition mode; and where it would have been the most and truly useful. In Normal acquisition mode the brightness differentiation of overlapping waveforms is clearly visible without any colors… As observed on both oscilloscopes, the 20MHz bandwidth limiting of analog input, has seemingly only worked once. This evidenced by changing noise level of open probe inputs, and where after initial activation it stayed “On” regardless of software control toggle. Without appropriate test equipment I could not say that with greater confidence. However, if aforementioned is true, the 200MHz oscilloscope has permanently turned into 20MHz underperformer… Both tools detected & displayed unexpected oscillation at 500µV/Div, when experimenting with Ground Coupling alike condition; where the probes were connected (but probes’ grounds were not connected to anything) to oscilloscope ground as shown in Pic-2. The Peak to Peak amplitude of mysterious oscillations was observed to be in the range of 2-3mV. When this may not be detectable in other circumstances, this correlates with earlier discussed tool accuracy concerns, and suggests deficiency of design; and looks like a pathetic “clock leakage”. Unlike other more developed oscilloscopes with “floating” to “grounded” probe switching option, the ground terminals of this tool’s channels are permanently grounded. Caution and concentration of the mine sweeper is required while working on grounded equipment. Oscilloscope’s manual explicitly instructs using 3-wire power only, thereby suggesting that no isolation transformer is allowed. There were other concerns with quirks in controls settings & operations, intermittent software snags with activating & deactivating certain functions; practically useless, and gimmicky PC software. Does this tool have any positive properties – yes it does, but quality issues, shortages in basic and explicitly promised functionality dominate, and result in overall low impression, and consequentially in no come back.