Lair Of The Multimedia Guru

July 4, 2016

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:
IMG_4764-small
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! ;)

Filed under: Electronics — Michael @ 3:45

3 Comments »

  1. Don’t know if it is too late, but I’ll answer anyway.

    I haven’t tried it myself, but I had plans to buy one of these: “aliexpress soldering iron t12 diy”. It’s a soldering station, but considering it’s price and features… DIY complect costs ~$25 and PSU for it ~$25. At the time I was searching for soldering iron there were lots of good reviews. It’s simple, cheap, uses Hakko T12 tips/their copies, operates at 12V (or was it 24V?), consumes ~80W, hence you can work with Plumbum-free solder, has temperature regulator and dynamic indicator, can turn itself off if you don’t use it (I think T12 tips have vibration sensor built in them), as well as dynamic control of tip temperature.
    Here’s a link to a first seller I found so that you knew for what to search: https://www.aliexpress.com/item/New-Electric-Unit-Digital-Soldering-Iron-Station-Temperature-Controller-Kits-for-HAKKO-T12-Handle-DIY-kits/32790086981.html

    BTW, once again I have yet to buy it, but here’s a good desolderer (it’s two different models): “desoldering Ningbo ZD 915 211”. Considering desoldering braid is not reusable, fully manual pump desolderers aren’t too good because you can’t position them right on top of the pin as fast as you need, and esp. considering that decent ones cost a lot, this one seems like the best option. You’ll have to search for more info yourself because I couldn’t find as much as I hoped.

    Comment by 8day — January 6, 2018 @ 11:54

  2. BTW, those soldering stations may need some extra adjustments on their boards, etc. (you should be able to find some hints on it’s improvement on YouTube). But IMO they are definitely worth their money.

    Comment by 8day — January 6, 2018 @ 12:00

  3. “Too late” ;) i have already bought this one as replacement (~13euros): (not meant to be a recommendation but it works and did not fail yet)
    https://www.aliexpress.com/item/EU-plug-936d-Digital-LCD-Adjustable-temperature-Electric-Soldering-iron-Electric-soldering-handle-220V-60W-10/32660074825.html
    ill consider your suggestion when that one fails, or maybe ill just buy it or a similar one so i have some redundancy.

    Comment by Michael — January 6, 2018 @ 17:27

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