Weak points of Harbor Freight DMMs

[David Nebenzahl]

I'm on my, oh, third el-cheapo (~$3) DMM (digital multimeter) from HF. Guess this one'll keep working fine if I can keep it dry and not stomp on it.

But today I was using it to test a bunch of transistors, using the handy-dandy "hFE" test function, and realized again what the weak points of these meters are.

The meters themselves are fine, so far as I can tell. I'm willing to bet that they're pretty much functionally identical and just as accurate as much more expensive ones. In other words, the guts are probably pretty much the same as any DMM on the market, apart from really high-end ones (Fluke, etc.).

No, the weak points are the damned connectors. I already knew how piss-poor the test leads are; you can practically pull the wires right out of them. Of course, these can be replaced with better ones.

But in testing those transistors, I had a hell of a time getting a decent connection. Had to twist and wiggle the xistor leads in the socket to get any kind of reading. Opened up the case, thinking I might be able to bend the contacts tighter or something, but the jack is closed on the back, so not possible. It's just a really poorly-made connector.

So long as one realizes this, one can still be content using these meters. They're still a great buy. How could you *not* buy a DMM for $3?

[WW]

I have bought several so to have one in each vehicle, in my work shop, in garage, and one in the living quarters. The test out equal to my Flukes. However never used to test transistors as I have a good transistor tester for that purpose. WW

[The Daring Dufas]

You can convert them to panel meters for that price. :-)

TDD

[aemeijers]

You PAID for yours? I got all 4 of mine with the free coupons (pre-purchase-requirement), paired with 20% off on whatever pissant consumable item (gloves, zip ties, whatever) I needed to stock up on that week. (I'm not quite enough of an asshole to go in and demand a freebie without throwing SOME business their way.) They are what they are- a low-end VOM good enough for quick checks and diagnosis work, and if you drop it or loan it to somebody and they don't bring it back, no big loss.

But to tie this to the recent thread about the freebies- I asked the clerk if traffic has dropped off with the purchase requirements, and she said it had. And the plastic scissors (the only recent freebie with NO purchase requirement) are, as expected, crap. I suppose they will be good for a few uses until the plastic pivot point gets wobbly, but for anything thicker/harder than 2-3 layers of cloth or paper, the blades will not maintain scissor action and spread apart. The plastic is just too flexible. Wiring scissors they ain't. Haven't tried the nutcracker/bottle opener feature.

[Jeff Thies]

I have no experience with HF multi meters but I bought a number of $3 MM from an outlet store. The electronics are fine, the test leads won't last and I am not surprised the transistor tester has bad contacts. Electronics are cheap, mechanicals is not.

I never cared what the gain of any of my transistors was. Just whether they worked and weren't leaky. A x10 scale measure from base to collector or emitter (both ways) was sufficient to sort the good from the bad.

Jeff

[George]

For the same reason I don't want 100 free harbor freight flashlights. I want something that works that I can depend on.

You essentially described why the cheap meter is useless: "I had a hell of a time getting a decent connection. Had to twist and wiggle the xistor"

[Mr.E]

I usually use a cleaning pad off a dish sponge. Clean leads by "grip and pull" and I notice very little problem making contact. Have seen older carbon resistors that were very difficult to make contact with. This is not a fault of the meter as I see it.

[Pete C.]

The appeal is that you can put a $3 DMM in every single toolbox (I have about 10 loaded for various tasks) and in every vehicle so you always have one on hand which will do just fine for every task you are likely to encounter in the field. AC voltage, DC voltage, resistance all just fine, and generally I don't need anything more detailed than that in the field. I have my good Fluke 87 in my shop along with my scope and other test gear which is where I do more involved stuff.

[JIMMIE]

Those transistor testers are practically useless, they just check DC gain. Better to check the front to back resistance of of all the transistor junctions using the ohmmeter function.

Jimmie

[JIMMIE]

I have a Fluke but also have my share of cheapies too. I find that by spending just a little more $10 I can get a much better meter as far as the cheap ones go, sometimes not. I like the small meters working around a power panel. I glue a magnet to the back of them so I can stick it up while Im working to free up my hands. Also have added a tab to them so I can hang them on a nail or screw them to where the front panel of a breaker box was screwed down. Not having to hold one of these in my hand while probing around in a live panel makes me feel a lot warmer and fuzzier.

Jimmie

[JIMMIE]

Same here Jeff, The one thing I worry about is if the insulation breaks down while using it. I dont want a fireball in my hand. Get you some decent probes to go with them. My probes have a built in fuse.

Jimmie

[Jim Yanik]

Jeff Thies wrote in news:ils1d9$k6m$ [e-mail]:

note that the HF DMM input impedance is One megohm. most DMMS are 10 MegR. another weak point is the soldered-on banana jacks,the joints crack and you get intermittents. also,the first HF DMM I bought read terribly high,had to return it for one that was more accurate. that's one thing I miss about mercury cells,they were a nice DMM check. you could count on them to be 1.35 volts.

[hrhofmann]

Fresh batterise are about 1.53 volts

[notbob]

That's the weak point of all of them.

As a one-time electro-mechanical technician, I was responsible for the DMMs on the production floor, buying, maintaining, calibrating, etc. Every meter but Flukes are junk. B-K, digital Simpsons, etc, all will start failing at the connectors. I've tossed so many broken meters, it's heartbreaking. Good guts, crap connectors, every one.

No, I don't own stock, but Flukes are the best meters made. The only meters I've ever seen that hold up under the most harsh abuse. Dropped, tossed in drawers, tools thrown on top of them, dropped in water, you name it. They jes keep on going. I had one so old the display had lost its frosting and you could see all the traces to the LCs. Worked fine, but a bit confusing to read. I still have an

8040B. I've seen a couple fail (the $80 autos), but NEVER seen bad connectors on a Fluke. Not ever!

Some things are worth spending the money on. DMMs are one such tool. Quit clowning around with junk and get the last meter you'll ever buy, a Fluke. ;)

nb

[David Nebenzahl]

On 3/17/2011 3:48 AM George spake thus:

That's only a fault with the transistor socket. I only used it for the first time the other day. Not the main function of the unit for me.

[Tom]

They are great for gifts and stocking stuffers. Then when someone has a problem you can talk them through how to use it and help them fix there problem. I can't count how many times I have told someone to look for the up side down U to test for continuity.

Tom Inspiration can be found in a pile of junk. Sometimes, you can put it together with a good imagination and invent something - Thomas Edison

[JIMMIE]

The Fluke is hardly the last meter you will ever buy. I see them go bad almost as quickly as the cheap ones. The big thing the Fluke has going for it is accuracy. If you need to measure down to the hundredth of a volt get a Fluke. Its also built with safety in mind but be damned if Im going to measure a thousand volts while holding the Fluke in my hand any quicker than I will a $3 meter.. The damage I see to meters is more abuse than anything else. From dropping them from top a

30ft ladder to measuring 440 while set to ohms. Buying a Fluke when you dont really need one is about like buying Snap On tools when your biggest problem is loss.. There are some really economical meters that will get-r-done just as well as the best.. I have a cheap little give away meter I picked up at a Powerware UPS class about 12 years ago still works fine gets used a lot.. But whenever I need to set a CRT beam current to 12 microamps or balance two paralleled 300A 5VDC power supplies I grab the Fluke.

Jimmie

[Robert Green]

Yep, depends on how you work. I even have backlit swivel head LED meters that plug into the car's cigar lighter that are very useful for battery checks that I keep in all the cars. I bought a bunch of Fluke copies for dirt cheap from Ebay's China vendors. Took a long time to get here, but it was worth it. Big numerals, auto off backlight, lots of functions, yellow rubber shell case - looks just like the Fluke except their's was named "Fuke" - really! Good enough for the phone repair kit and I got another for the CATV wiring kit.

It all depends on how you use them and what you use them for. Even have a raft of meters (Metex and RatShack) that interface with a PC and can be used to record readings from any scale/range/function. Useful to monitor the powerline, make temperature fluctuation graphs, etc.

-- Bobby G.

[larry moe 'n curly]

The meter probes attach to a small, narrow circuit board that's connected to the main board only through solder blobs, and that solder may eventually crack from mechanical stress. So I bridged that solder with short segments of solid copper wire.

One of the meter tips pulled out easily when I stuck it into a 120VAC outlet (GFCI protected) but has been very secure ever since I pressed it back in. Meter accuracy was very good on DC volts and ohms.

The LCD is slightly better than my Fluke 73's and has a wider viewing angle, either horizontally or vertically.

[notbob]

That does no jive with my firsthand experience. When I was maintaining them, we had 2 failures out of 200 meters over a 4 yr period. I suppose Fluke quality may have gone down in the last 15 yrs, but I find it hard to believe Flukes are now failing as often as cheapo meters. Sorry, but I just don't believe you.

nb