| Electronics > Projects, Designs, and Technical Stuff |
| UT61E vs Ionizer |
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| joeqsmith:
There have been people on these forums that have spent a lot of time trying to revive a low cost meter like this. I typically test the meters to failure and will have a quick glance to see if they can be repaired. That is one of the things I see with the better class of meters. They have enough protection that normally the controller ICs are not damaged and I am able to repair them. The lower class of meters, it's rare I can do anything besides recycling them. |
| cdev:
What can be done to preemptively mod the meter so it wont be as susceptible to damage, and does it reduce its accuracy? Backlight- not so important to me - durability- important to me. |
| joeqsmith:
The best thing you could do is buy a better class of meter to start with if you are playing with HV's like the OP is. The worst thing you could do is to modify a safety device in any way. That said, it may be possible to use something like I show in the following video. https://youtu.be/bj_YndfA4Qs |
| MosherIV:
--- Quote ---What can be done to preemptively mod the meter so it wont be as susceptible to damage, and does it reduce its accuracy? --- End quote --- Add the MOVs, they are marked on the PCB but have not been installed. Not sure if it will totally protect the meter. They should clamp the input voltage in case of an over volt. I have done it to my ut61e. The only measurement it have affected is the capacitance. Joe has done some tests. The MOVs he tested did not give total protection to the meter. It did survive some over voltage if I remember correctly. |
| joeqsmith:
You are correct that adding the MOVs would have never saved my meter from the piezo gas grill ignitor. The nature of poor UNI-T designs I'm afraid. I made a few videos showing the problems and how I addressed them. As you suggested, I did run several transient tests after making the changes to demonstrate them. Just to be clear, while it was mentioned in that video and others, when you start dealing with waveforms in the ns with rise times in the ps there is a lot that will come into play. Just sprinkling parts onto a board may not prove to be effective. |
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