If I were stranded on a deserted island trying to fix the radio, I would be happy to have one of these. Otherwise, they’re the subjects of a study in how to make DMMs as cheaply as possible.
Purchased at Harbor Freight for $2.99 on sale. This is the one with the back-light. Of the two samples documented here, this was the better one. Obviously it would not hold up to continuous use, but it did give accurate repeatable readings.
Also purchased at Harbor Freight for $2.99 with a coupon. This one looks a lot like the one above, but without the back-light. The build quality (relatively speaking, of course) was not as good as the back-light model. It gave steady repeatable readings on DC and AC volts, but in resistance and milli-amp modes, it would never give the same reading twice.
Update #1: After re-soldering the input jacks, replacing the solder bridges with some copper braid, and tweaking the calibration pot, the 69096 meter functionality improved to be on par with it’s backlit cousin. I get the feeling it’s ‘luck of the draw’ with these things.
Update #2: Everybody seems to have an opinion about these little red/yellow boxes, but I find myself disagreeing a bit with some of the stuff I read and hear online. So let’s do a little myth-busting.
Myth #1: These 830-style DMMs are not accurate.
Actually, the ICL7106 Analog-to-Digital Converter/LCD Driver clone (under the black blob) is extremely well-suited for rendering very accurate DC voltage measurements. It is quite possible, even probable, that it can easily match a more expensive DMM digit-for-digit on the DC voltage scale, especially if the calibration trimmer is tweaked. (Some of the latest ones do not have a trimmer.) For functions other than DC volts, more variables are involved, so the word “ballpark” becomes operative.
Myth #2: “It matches my buddy’s Fluke, so it’s just as good as the Fluke.”
No, it isn’t. The Fluke is made to be reliable, remain accurate, and last many years and provide measurement confidence. This unit is made from a dollar’s worth of cheap parts and cheap plastic, and it’s a crap shoot as to whether it will remain structurally intact for any length of time. The leads are particularly short-lived.
Myth #3: It will explode and kill you if you use it to measure the mains.
If the meter and leads are in good condition, and you plug the leads in and set the switch correctly, it should measure up to 240 VAC in a standard residence with no drama whatsoever. No explosions. If the leads are plugged into the 10A current jack, or the range switch is set to ohms or current, then you might get sparks, smoke, and startling noises. Unless you’re holding the meter in your mouth, the only fatality is likely to be the meter itself. But please, don’t use this device anywhere near commercial/industrial distribution panels where deadly arc flash incidents are actually possible.
Myth #4: These are good enough for a beginner or an amateur at electronics/electricity.
These things can definitely lie to you. Low ohms measurements are likely to be way off. The AC voltage ranges are DC-coupled and will appear to read non-existent AC voltages in the presence of DC. The unreliable nature of the leads, the rotary switch, etc. can result in inconsistent readings at inconvenient times. This means trouble for users who cannot easily differentiate between a real fault and a failure of the measuring device. Novices do not need a $200 DMM, but they definitely need something reasonably reliable that is less likely to give misleading readings.
Just $20 can get you a tool that is an order of magnitude better than these toys.