voltage tester

DMMs are usefull but for some things they are a bit inconvenient and bulky. So for fun and less so for potential usefulness i bought the 8 in 1 voltage tester depicted below, smaller than a DMM, puts a small decreasing load on the tested circuit allowing things like GFCI testing and so on.
IMG_4760-small
But when testing at 220V AC it produced:
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In fact the 380V LED lights up down to 175V.
Opening the thing up without destroying it proofed to be some effort, the inside:
IMG_4765-small
I was already starting to trace things and draw a crude schematic to debug this when i noticed:
IMG_4769-small
A unpopulated component, for a fraction of a second i considered a optional features quickly discarding that in favor of the hypothesis of excellent quality management in this ultra high end (it cost almost 5 euro) tool.
So after a bit of thinking, guessing and testing i wanted to solder a 100k resistor in there but my 10-15 euro variable power soldering iron didnt work anymore. That one was even from a local shop not ebay. Luckily i still had my grandfathers soldering iron:
IMG_4771-small
Which after exchanging the tip worked perfect:
IMG_4772-small
and after that all voltages work fine, including 220v:
IMG_4773-small
PS: Recommendations for a good and cheap variable power soldering iron are welcome! ;)

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