DT830 multimeters

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Another meter is fried again today!!!

I have six meters blown in 2 years, while reading high voltage AC.
I guess I will find a better alternative for such reading.

Is there a way of fixing spoilt meters!?.

We are talking about this kind of DT830 type multimeters:

My answer:

Those three on the right are basically the same dt830 design with very slight variations. Those are known to work OK on low voltages but are not well designed or protected against high voltages. Some DT830 meters have ended to sales ban lists because are not safe for mains voltage mesurement. I own several dt830 based meters and use them only with low voltage circuits. For mains voltage circuits I use known brand 1000V rated meter!

Some info on dt830 meters – technology and repair information:
https://www.petervis.com/meters/dt830d/dt830d-repair-and-fuse.html
https://www.petervis.com/meters/dt830d/dt830d-circuit-component-values.html
https://forum.allaboutcircuits.com/threads/dt830d-digital-multimeter-repair.165464/
https://www.scribd.com/document/405317612/Digital-Multimeter-DT830B-schematic-diagram
https://www.instructables.com/Digital-Multimeter-Kit-Build-DT830B-DMM-Electronic/

They are this kind of cheap multimeters

Here is DT830B circuit diagram from https://www.hobby-hour.com/electronics/dt830b-digital-multimeter.php

These meters are not designed for high voltage AC. They work quite OK for low voltage measurement.
Don’t buy or use cheap meters to measure high voltage.
Buy Fluke, Agilent, Keysight or another known brand. The quality does matter when your life is on the line.

8 Comments

  1. Tomi Engdahl says:

    Cheapest DT830 multimeters seem to cost $0.99 on ebay

    Reply
  2. Tomi Engdahl says:

    How to use your trashy meter without blowing it up (much)
    https://www.youtube.com/watch?v=-QDW0LRQVrY

    Your first multimeter can initially seem a bit daunting with all the modes, but the only way to learn is to get one and play with it. I damaged my first meter when I was young by using it on the incorrect range. You can damage these cheap meters, but at the cost you don’t have to worry about it too much.

    I probably made this video too long and complicated, but it’s useful to know how things work as well as how to use them.

    The very cheap meters sold for around 5 $/£/€ are usually pretty accurate for their cost and very usable. Once you’ve mastered using one you can move up to something with more features or more suitable for industrial work. These cheap meters are NOT suitable for poking around in distribution boards or industrial equipment with high fault current.

    Meters have a category rating as follows:-
    Cat I – electronic use (these cheap meters)
    Cat II – electrical appliance, but not fixed wiring or distribution boards
    Cat III – general electrical maintenance in panels and machines
    Cat IV – utility level work with very high fault currents

    For industrial work I recommend Fluke as it appeases the clipboard warriors. There are many other brands suited to industrial use too. Beware cheap meters with fake category ratings.

    Reply
  3. Tomi Engdahl says:

    Tuotenimi: Laser 6228
    https://marek.tukes.fi/Tuote.aspx?nettijulkaisuId=10694

    Toimintaohjeet

    Tukesin päätöksellä talouden toimija on määrätty lopettamaan tuotteen myynnin ja muun luovuttamisen; mukaan lukien uudet toimitukset jälleenmyyjille. Koska tuotteesta ei aiheudu välitöntä vaaraa hengelle, terveydelle tai omaisuudelle, talouden toimijaa ei ole velvoitettu keräämään tätä tuotetta pois jälleenmyyjiltä tai loppukäyttäjiltä. Kuluttaja voi kuitenkin kuluttajasuojalain mukaan palauttaa tuotteen virheellisenä (turvallisuusvaatimusten vastaisena) ostopaikkaan, jotta myyjä voi korjata sen vaatimusten mukaiseksi. Ellei korjausta voi tehdä, on myyjällä oikeus antaa korvaava tuote tilalle tai viime kädessä kaupan saa purkaa. Menettelystä on kerrottu tarkemmin kuluttajansuojalaissa.

    Toimenpiteen syy

    Tuote ei täytä sähköturvallisuuslain (1135/2016) eikä tuotetta koskevan eurooppalaisen harmonisoidun standardin EN 61010 vaatimuksia. Mittarin mittapäiden eristämätön osa on liian pitkä verkkojännitettä mittaamaan pystyvälle mittarille.

    Reply
  4. Tomi Engdahl says:

    $3 multimeter test & teardown
    https://www.youtube.com/watch?v=R693vS09hoo

    Today I test a cheap multimeter from Ebay for 3 USD including shipping (DT830B knock-off). Does this thing work? Is it safe to use? What’s inside? Let’s see in this video :).

    Viewer comments:

    Another great video, thank you! Your lovely CAT1 is right – take HV measurements at mA range but please be careful(!). Also, I love your hand-drawn schematics, you’ve got a damn talent. All the best and greetings from Poland.

    I got one of these a year ago and I was surprised how accurate it was, especially when compared to much more expensive meters.

    But I don’t expect it to be very durable.

    The first one of these I had I was checking 240 Volt AC and had the dial 180 degrees wrong way at the ohms setting by mistake. There was a big flash, a loud bang and a new pair of underpants required. But started my intrest in multimeters.

    The metal strips from the probe connectors are the fuses. They work like the battery fuse in your tesla. The metal strip is designed to melt at a specified current, and this way you don’t need a fuse. Look at the left metal strip where it meets the board. It has a notch in it where it will melt.

    The best DT830B variants are those from the 90′s. They use all through hole parts and everything is just better. Not necessarily prettier to the untrained eye but still much better quality. I don’t know about the UNI-T brand which also has a DT830B in the menu and it’s a little different in the transistor connections. But otherwise probably the best DT830B you can get is the DIY/kit version. That has large through hole resistors, fuse and large 10A resistor too – not too far away from your older version. The downside though is you have to calibrate it yourself so investing in a good voltage is recommended. They’re not too expensive though and may come in handy for other things too – so no need to invest in an expensive lab multimeter in order to calibrate it more than good enought for any use you’d sanely use a DT830B for.

    DioneGoneWild: it appears from your testing that the rotary switch of these “smaller 830B” has much more contact problems than the almost identical switch on the larger/older meters. I mean, they were a bit flaky on the older ones as well, but not that bad. Is there really a difference between them?

    I found this multimeter to be very accurate. 95% of the time. The other 5% of the time it would show wildly exaggerated readings. Accuracy isn’t enough – consistency is necessary of one is to trust a measuring instrument. Consequently I threw mine in the bin, and would not recommend anyone buying one of these.

    This exact type of meter has been made almost identically for decades, it literally looks the same as my first meter I got in 2001, only that the circuit board on this one is smaller, crappier and simplified to the bone. The warnings on the back about the fuse are probably there because they use the same exact injection mold for the casings for all variants of the meter. They are OK as basic meters, their weakest point actually being the crappy leads.

    Reply
  5. Tomi Engdahl says:

    XL830L Digital Multimeter
    http://www.dgmeters.com/product_3755.html

    This is an XL830L Digital Multimeter for measuring DC and AC voltages, DC currents, resistors, diodes and transistors, which is battery powered. It is very simple and effective and very practical for electricians. Easy to operate, readings are displayed directly on the screen. It can be used to access a variety of boards. It is also an ideal teaching tool for students…

    Reply

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