1. Problems
Recently I found a Geiger counter on Amazon which can't work well. After trying so many ways to find the problem, finally I figured out. It just can't convert 5V to 400V. I had ever thought that maybe it is just because the so closed copper trace, which need to bear a 400V power line, has got electric leakage. But I still can not get a stable 400 voltage conversion after I have tried to recreate the circuits on the breadboard.
2. Replace the voltage converter
This is the original circuits which is also an open source project, Geiger-Counter-RadiationD-v1.1-CAJOE. I replaced its converter with another project on Geiger counter.
Here's the final version of this PCB (there's no values on the board).
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