-1
\$\begingroup\$

I have a digital multimeter DT830B, and I suspect it is damaged. I think sometime ago I tried to measure something wrongly, and maybe I broke it.

Its display is working OK. When I turn it ON, it shows me some numbers varying and then goes to 00.0.

I try then to measure voltage from an electrical plug or battery, but the numbers stay at 0.

How could I test the multimeter itself, or the cables (red and black) used with it, to try to discover what is wrong?

I tried to open it to find a fuse, but could not identify any.

update:
I opened the device again, and I think I managed to see why it's not working: the "fuse" is really burnt, but this one is "printed" in the board, as you can see in the image. I think if I solder it again it maybe work. Its construction is really very ordinary.

multimeter board PCB trace

\$\endgroup\$
4
  • \$\begingroup\$ Get another DMM and measure the voltage and current in the resistance, diode, and continuity modes, and the resistance in the voltage and current modes. \$\endgroup\$ Commented Jun 3, 2015 at 19:00
  • \$\begingroup\$ possible duplicate of Using a multimeter \$\endgroup\$
    – Kaz
    Commented Jun 3, 2015 at 19:25
  • 1
    \$\begingroup\$ You can buy a DT830B new for about $5. You can probably buy a secondhand Fluke for about $25 on eBay. The Fluke will be more resistant to misuse, more accurate and will have autoranging and other useful features. Don't spend too long trying to fix your DT830B after checking the fuse. \$\endgroup\$ Commented Jun 3, 2015 at 19:42
  • \$\begingroup\$ I don't see any trace of a "printed on" fuse unless it actually blew away the corner of the PCB. Check the other side of the PCB \$\endgroup\$
    – Oskar Skog
    Commented Feb 4, 2017 at 10:56

3 Answers 3

4
\$\begingroup\$

The DT830B (in fact any DMM with 830 in the part number) is well known as the cheapest and least safe DMM available. If you think it is broken, throw it out. It is not worth repairing. In any case, you can get one free at Harbor Freight. If you plan on doing work that will require a DMM, then get a better one. A used Fluke is certainly a good choice but there are other brands such as HP. They cost more but are much more reliable and safer.

\$\endgroup\$
2
\$\begingroup\$

Did you see something like this?

enter image description here

The top item is a fuse. The bottom one appears to be a current measurement shunt. Chances are that if you put voltage on a high current range the traces going to the shunt would be blown off rather than the shunt damaged. If either the fuse or some traces are open (you can see the thin hair-like element inside the glass 500mA fuse) then some functions of your multimeter will not work.

\$\endgroup\$
3
  • \$\begingroup\$ #2 is a fuse? Where is the shunt then? \$\endgroup\$ Commented Jun 3, 2015 at 19:19
  • \$\begingroup\$ @IgnacioVazquez-Abrams It looks like a shunt to me, but the guy with the web page claims its a fuse. Probably he's wrong, I'll change the answer. \$\endgroup\$ Commented Jun 3, 2015 at 19:21
  • \$\begingroup\$ Some multimeters with the same model number don't appear to have this fuse on the more easily accessible side of the PCB. \$\endgroup\$ Commented Jun 3, 2015 at 19:49
0
\$\begingroup\$

You need to open the case as the manual says. When using a multi meter be careful that you have the meter set for the correct range and measurement type and the test leads in the correct sockets. Also do not try and measure resistance in a powered up circuit or place it in the current or resistance measuring mode across a voltage source. AC voltages will not usually register on a DC setting and an AC setting may or many not display a DC voltage. If you think the cables are bad place it on the lowest ohms range touch the cables together you should see a reading close to zero. However unless you have yanked on the cables and they have pulled out of the connectors they should be okay.

Its easy even for an experienced technician to put the meter on the wrong scale and burn up a meter. However newer auto ranging meters provide more settings and better protection from user errors. I still like to use the old galvanometer movement meters for some applications where I want to place a small load on the circuit being measured to avoid erroneous errors from using a high impedance digital meters. If you see or smell burnt components (usually resistors) they will have to be replaced before you will be able to use all the available functions. Go to this following web page for your owners manual.

http://rental-shack.com/jm1ljs/webshop/manual/DT830_English_Manual.pdf

\$\endgroup\$

Not the answer you're looking for? Browse other questions tagged or ask your own question.