Just got my 4065A a couple of days a go, and been playing around with it. Nice to have such a comprehensive multimeter!
But there are quite a few bugs that i have encountered so far. So the firmware could use some improvement still.
Here is a weird bug:
2W resistance: Turn on Auto Ranging and Auto Zero. Short the input leads to create zero ohms. The instrument shows about ~0.007 ohm. All ok so far. Then remove the short. You would expect the meter to measure open "overload" in the 100Mohm range. But nope. Mine shows about 0.014 ohm (slight fluctuating) and sometimes tries to switch to the 200k range, before going back to the 200ohm range. When i disable Autozero, the measurement functions correctly again. This only happens on auto range, when using fixed ranges everything works correct.
And another bug/issue? On 2 wire resistance, when i just plug in the upper test lead, the meter already measures ~20Mohm. When i unplug the upper test lead the meter measures >100Mohm. This might be an earthing related issue here in the lab to be honest, but yeah this makes measuring anything above 20Mohm impossible.
The whole datalogging and digitize functions are a bit unreliable. I had instances where the digitize function would continuously alternate between the true value of the signal and zero volt, when i was just measuring 5V from my lab supply. Exports to csv from both the datalog and digitize would sometimes result in the same incorrect values. I dont have a way to reliably reproduce this problem.
It isnt really clear when you are in Continuous acquire mode that you are also recording, at what speed, and where in the recording memory you are exactly. You can save the recording from the Acquire menu, but in order to delete/reset the recording you have to go in to the Trend view. But in trend view you cant save them, you have to go back to Number view -> Acquire. A bit messy if you ask me.
The Start value in the CSV export had a bit of a weird notation. For example:
"Start date:,2025-09-05,Start time:,14:15:08.3.375781"
Is it showing milliseconds or what?
And maybe it would be nice to have better options to navigate (zoom, scroll, etc) through Histogram and Trend view?
And as a final issue, windows keeps nagging about the usb stick needing to be repaired after it has been used in the sdm4065a. There seems to be no data corruption however.
That is what i have so far
