#09 Rigol DM858 DCV Impedance failure - part 7
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- เผยแพร่เมื่อ 6 ก.ย. 2024
- Very low impedance DCV failure during autorange - a new discovered bug in the same Analogue Front End of the DM858 (and also E version I assume).
It can destroy / change behavior of your Device Under Test as it draw relative high current from it.
It can destroy your multimeter i.c.w. high DC voltages apparently (2 reports of final defects)
Thank you for documenting all of this.
Thanks for the test friend, I had commented on this in your last video, apparently this has not yet been corrected, as you received a version with the most up-to-date hardware, unfortunately they will have to correct a few more things, my multimeter after I measure a voltage of 400V showed an internal resistance even though there were no tips connected, I have these videos saved. The rigol representative at the time authorized me to open the multimeter so I could try to correct it, I managed to find the defective component, it was a transistor that went on the run after measuring the PFC of a source, if you want, send me an email and I'll send you the videos and photos of this defect that occurred and the component that I replaced to correct it.
Good day. Thanks for your reply. I am very interested in your videos and photos. I would be nice to understand more about the (bad) design of Rigol. My email address is marcel.yt@kpnmail.nl Thanks a lot !!
Please make a video while rectifying the issue
What do you mean with rectifying? Impedance issue?
Rigol should ditch this, recall all sold devices and come up with a decent successor!
Indeed. I think it is not acceptable. I don't understand that they didn't find this bug by themselves during Quality Tests / Quality Control.
I contacted Rigol with same fault. Reading milivolt in auto range when connected to around 30volts. They came back with : send Scpi command : System:cfgver 1
I have done that. Since then autorange working fine.
indeed, the 30 Volts topic is away via the SCPI command. But the Impedance and 100mV/1V manual overload conditions remains unfortunately. See also my latest video why you should avoid using Autorange th-cam.com/video/Zf48CLWF1pA/w-d-xo.html
Thanks
Я так понимаю ,проблему с низким входным сопротивлением в режиме DCV так и не решили .
The workaround is to use manual mode (not auto). Since in Auto it will always go one time through the low impedance phase once you connect the tips to your DUT. Hopefully Rigol will come with a fix I hope......
@@marcelmostert3081 Я тоже на это надеюсь . Но прошло уже 2 месяца , как я отправил видео с ошибкой на сайт rigol , но ответа так и нет . Я изменил схему на приборе , поставил реле в разрыв термистора , а реле запустил от светодиода DCV .
Доброго времени суток. А не подскажите, чем это черевато?
Хорошо, что я не купил это.
i thought the issue was only for DM858E,my hardware version is 1.0
I guess the Analogue Front End of the 858 and 858E are the same.
The old issue for repairing the Autoscale 28-40Volt seems to be solvable via :SYSTEM:CFGVER 1, also on HW1.0 But the new identified low impedance issue is something else (for me).
@@marcelmostert3081 Could you explain how to use this :SYSTEM:CFGVER 1 setting? I have a DM858 with HW1.0 and would like to sort this issue if possible?
I am not sure but I thought you have to set it to 1. In my new HW1.0.1 version is was apparently already set by Rigol - without knowing by me that this setting was applied. Nevertheless meanwhile I have discovered that even with :SYSTEM:CFGVER 1 the problem is not completely solved. I will probably make a new video about it.
@@marcelmostert3081how do you actually set this variable though?
@@keyboardjunkie6287Try this: send SCPI command from a PC using a USB cable as below and then restart the multimeter:
Send :SYSTEM:CFGVER? to see whether the return value is 1;
If not, then send :SYSTEM:CFGVER 1