Products > Test Equipment
New 2ch pocket DSO+SG - Zeeweii DSO2512G
chemary:
Thanks @Dry for confirming that is not only my device. It seems there is a software bug, the problem is that the vertical displacement is not took into account in single mode, it adds the offset to the measurements. I have sent a message to Zeeweii support and I'm still waiting their response, I hope they release a fix. What seems strange to me is that there are no more reports of this issue as it seems pretty easy to replicate, maybe only affects last firmware revision.
This is the refined way to replicate the problem:
1. Connect the integrated Function Generator to CH1
2. Configure the integrated Function Generator to 1Khz square wave
3. Click "Auto"
4. Go to "Measurements" menu and enable "Mean" "Min" "Max" (all absolute voltages are affected)
5. Check that "normal" and "single" mode display correct measurements (clicking "Run" and "Single" alternatively)
6. Move signal up with up arrow "^" for instance 500mV
7. Check that "single" mode display invalid measurements (measurements are increased by 500mV)
It would be great if the Vertical/Horizontal offset is displayed somewhere when you move the signal around as most oscilloscopes do, it would have helped to spot the problem.
Dry:
--- Quote from: chemary on January 09, 2024, 10:32:15 am ---It would be great if the Vertical/Horizontal offset is displayed somewhere when you move the signal around as most oscilloscopes do, it would have helped to spot the problem.
--- End quote ---
In fact there is no vertical offset, the waveform is displayed correctly in SINGLE mode as well as in AUTO. Only the measured values are incorrect, but where is the zero used for that miscalculation - that is the mystery. The waveform position is automatically set in AUTO mode; when using the built-in generator this zero in far below the central line and it seems be used for every position of the waveform on the screen in SINGLE mode. Afaik the only way to measure the waveform correctly in SINGLE mode is to use the cursor lines (see below).
Aldo22:
Yes, this seems to be a bug.
However, there is a simple workaround on my device.
After you have moved the offset, press "Run/Stop" once (from the "Auto" state).
This also seems to update the offset values for "Single", so the correct values should be displayed afterwards when using "Single".
Simply repeat after each time you move the offset.
chemary:
--- Quote from: Aldo22 on January 09, 2024, 12:47:19 pm ---Yes, this seems to be a bug.
However, there is a simple workaround on my device.
After you have moved the offset, press "Run/Stop" once (from the "Auto" state).
This also seems to update the offset values for "Single", so the correct values should be displayed afterwards when using "Single".
Simply repeat after each time you move the offset.
--- End quote ---
Thanks @Aldo22, I tried and it works, not ideal but at least we have a way to get correct readings.
peter__s:
--- Quote from: timschuerewegen on October 20, 2023, 04:49:51 pm ---It should also be possible to read/write the SPI flash chip via USB "FEL" mode but only if you can insert a microSD card into the microSD slot, so you can enter USB FEL mode, which is impossible to do since the battery connector is in the way >:(
--- End quote ---
Some thoughts about solving this issue:
While cutting SIM cards from Mini to Micro or Nano was popular, judging by pictures from the WWW from data recovery specialists, it seems to be a bad idea to shorten microSD cards so that they can be forced into this slot. Likewise, trimming the PCB-side battery connector is certainly an easy mod, but it would remove the bits that keep the battery-side connector in place. https://www.reichelt.de/raspberry-pi-microsd-verlaengerung-flexibel-15cm-rpi-msd-fl15-p223611.html should also work... or:
* One option seems to be to add a new (micro)SD card socket (e.g. a microSD to SD adapter) connected with wires, without changing anything else. One could even orientate it sideways and dremel the housing allowing easy access.
* I considered unsoldering the bottom two pads of the microSD card socket and tilting it a few mm up, allowing the card to bypass the battery connector. I happened to have some chinese device with the same microSD card socket that I decided to experiment with. It turns out, that the release mechanism contains a small but powerful spring. The card socket's housing has two pins sticking out of its bottom surface into matching holes in the PCB to help protect the solder pads from mechanical stress.
While careful handling would allow occasional card insertion or removal and hot glue or epoxy could be used to fill the gap and secure the socket in its new position, removing the spring requires unsoldering the remaining two pads of the socket's top and further exposing its innards along with abandoning its ejection mechanism.
Replacing the socket with a top-loading or short alternative like Molex 105162-0001 seems more favourable but involves more soldering and risks.
* Another approach would be to unsolder the battery connector from the PCB and either replacing it with one that faces up and offers more clearance or using its pieces to achieve something similar.Has anybody solved that yet?
What are your thoughts?
I was likely to try the third option soon. But upon writing this post, I astarted thinking that simply trimming the top with sharp scissors is the quickest of all quick-and-dirty approaches, allowing to insert a card at an angle and bypassing the battery connector. After trying that with my donor socket mentioned above, I decided to carefully bend the oscilloscope's microSD socket top up with a small screwdriver instead, allowing me to insert and remove cards after unplugging the battery without further modding.
Please note that the nineth contact of the microSD card socket (allowing to detect whether a card is present or not) is not connected to the F1C100s (while all others are). Hotplugging is probably a bad idea.
BTW, I have PCB V9.15 with FW 1.3.0C
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