Voltcraft DSO 1202D goes crazy right after a few seconds from booting - Page 1
Forum section: electronics / repair

author: rugo100
author_rank: Contributor
timestamp: November 23, 2024, 09:07:21 pm
content: Hi,my Voltcraft DSO1202D after a few years fine working yesterday went 'crazy' when I was checking a PWM circuit prototype.Since that time when I switch it ON it is booting well and seems to be functioning well but after 10-15 seconds normal work it starts 'hanging', no response for button pressing it starts itself to do different things randomly (like somebody would pushing buttons randomly).So, it is totally useless now.I would very grateful if somebody would give me idea what the problem can be and what would possible to do to repair it.Thank you.I already have tried to do system recovery without success(ON-OFF and ON again)

author: rugo100
author_rank: Contributor
timestamp: November 25, 2024, 08:02:58 pm
content: I had more time so I made some research on the behavior of my 1202D.power ON is OKbooting, Voltcraft logo appearsthen scope usual screen appearCH1 MENU, MATH Menu, CH2 MENU, AUTO SET and RUN/STOP lit but no response for single pus on buttons or selecting a function.Seems to be the device hangs.Although it does not work but a bit of life is in it (behind the scenes)E.g. if I push a function button and keep it a bit longer time the corresponding function screen appears.Also if I touch nothing osmetimes the device changes screen/function on its own.Another interesting thing is if I connect a memory stick the system is recognise it, the disk icon appears on the top of the screen and even I was able to use the 'Update' menu of 'UTILITY' and I have successfully updated the firmware.Unfortunately after the update then reboot the device behavior is the same as I described above.Another thing what is working that is the boot menu.With the booting cycle(ON/OF then ON again) the system recovery menu appears and I can start the system recovery function.It is finishing well but unfortunately the device behavior is same as before.like the next step I wanted to connect to the device on UART to see if I can access the operating system or not.To do this was needed to find UART RX/TX pin inside the device. After a while I found them. See the attached picture.I have connected an USB-Serial converter then via a terminal emulator was possible to access the system (connection speed 115200bps)eg unix LS command is OK (see picture #ls)See terminal screen after booting the scope (see attached)So operating system on the device seems to be operational.At this point if I use a function or menu button (push shortly) nothing happen on the terminal but if the push it longer (2-3 secs) some corresponding sequence appears on the screen.Eg if I push CH1 MENU button shortly noting can seen, but If I keep it pushed longer then on terminal I can see this:"t_unscan_wave_vertic_operate:ch0:5, 5factor:chid0, vb:5, pos:0, factor:1.088000Disp_SyncChOnOff:inyt_unscan_wave_vertic_operate:ch0:5, 5factor:chid0, vb:5, pos:0, factor:1.088000Disp_SyncChOnOff:inyt_unscan_wave_vertic_operate:ch0:5, 5factor:chid0, vb:5, pos:0, factor:1.088000Disp_SyncChOnOff:inyt_unscan_wave_vertic_operate:ch0:5, 5"Well, based on above finding I think my scope is not totally dead, but unfortunately I do not know what can/should I do with it to get back a functional device.Is the problem whether hardware or software related?If somebody has idea please tell me.Thank you

author: Fenstergucker
author_rank: Regular Contributor
timestamp: November 28, 2024, 09:49:06 am
content: I assume your Voltcraft DSO1202D is from Hantek. Does it have a battery for the RTC?I have a Hantek DSO1202B handheld that no longer has a Li-Ion battery and no battery for the RTC. When I switch it on with the power supply, it behaves exactly as you described.But if I set the time and restart it, it works normally again. Setting the time is sometimes difficult because the keys play crazy.Peter

author: coromonadalix
author_rank: Super Contributor
timestamp: November 28, 2024, 10:02:46 am
content: you see a coin cell holder in the op pictures ... near the buzzer

author: rugo100
author_rank: Contributor
timestamp: November 28, 2024, 09:22:24 pm
content: yes, there is a 3 volt battery in it.It was almost totally empty, 0.xx voltI have replaced it with a new one, but since the buttons are 'crazy' I could not set the time.Now I go and try to set it.Thank you

author: rugo100
author_rank: Contributor
timestamp: November 28, 2024, 10:45:54 pm
content: Now I am thinking about that what happened when my device went mad?It was connected to a pin of prototype circuit checking a PWM signal on it then I left the room. About a hour later I wanted to take a look on the proto again but I realised my DSO is hanging. I switched it OFF then ON but since that time it behaves as I described.Later time I opened the box to check the device and I found the battery discharged. I have replaced it to a new one but the device behavior remained the same as it was before. The drying of battery and the device failure happened suspiciously same time therefore that can be the cause of the problem.But I have not got a clue whether what for that battery is in the DSO. Is it really the power source of a built in RTC? What that RTC is for?I have looked over the whole manual but I could not find any settings what would set the time (RTC). Next to this since the front panel buttons are 'crazy' very hard even select a function.Do you or somebody knows what is for the 3 volt coin battery in the DSO?Do you or somebody knows what should set after this battery replacement?Thank you.

author: rugo100
author_rank: Contributor
timestamp: November 28, 2024, 11:13:17 pm
content: I found the RISC processor of my DSO S3C2440X has a VDDRTC pin (with other word in it is an RTC integrated) so the battery is probably connected to this pin supply with power the RTC when device is OFF. It is OK but then still I am looking for the answer for the question what is the function of this RTC in a DSO oscilloscope?

author: Fenstergucker
author_rank: Regular Contributor
timestamp: November 29, 2024, 05:21:30 am
content: I have temporarily connected a Li-Ion battery to my Hantek DSO1202B handheld. With the battery, the oscilloscope works normally after switching off and on. When I remove the battery and reconnect it, it goes crazy and the time/date is 2009-01-01.I can also set the time via the USB connection using the DSO-USB-Tool. After a restart, the oscilloscope works normally again. Whether this is a coincidence every time, who knows.With a Voltcraft DSO3062C (Hantek) you can set the date under 'Utility' -> 'Page 2' -> 'Time'.Peter

author: rugo100
author_rank: Contributor
timestamp: November 29, 2024, 05:36:38 pm
content: Hi Peter,thanks for information. SInce your device is quite different as mine I am not sure the reason is that of behavior of my device.Since my device so 'crazy' I am not able to set the time (I had very hard time to even select the "Time" menu but when I got it it disappeared within a seconds or two)Because of this situation I am looking for a fellow guy who owns a Voltcraft DSO1202D or an identical Hantek device (one of DSO5000 series) and who is brave enough to temporary remove coin battery from her/his device to see how it behaves.Thank you in advance.