FREE Centech DMM's - Page 1
Forum section: electronics / testgear

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 01, 2014, 07:20:29 pm
content: Harbor Fright giving away DMM's no purchase necessary. Trust it???

author: Bored@Work
author_rank: Super Contributor
timestamp: April 01, 2014, 07:27:32 pm
content: Just hazardous waste they give away. Cheaper than properly disposing them.

author: Mr Simpleton
author_rank: Unknown
timestamp: April 01, 2014, 07:32:02 pm
content: Hey, Think I got one just like that few years back... it was and still is rubbish!Maybe you can poke out the battery to use....Worst thing is that it reads totally off when battery is low, so it is dangerous to use to say the least!You have been warned.....

author: ErikTheNorwegian
author_rank: Frequent Contributor
timestamp: April 01, 2014, 07:55:28 pm
content: That must be oposite to customer care to give avay such a dangerus meter...

author: TVman
author_rank: Frequent Contributor
timestamp: April 01, 2014, 09:11:07 pm
content: I want it!I can't afford A fluke.

author: free_electron
author_rank: Super Contributor
timestamp: April 01, 2014, 09:16:59 pm
content: its cheaper than having em destroyed. grey face, flashy bumper. fluke trademark

author: ju1ce
author_rank: Regular Contributor
timestamp: April 01, 2014, 09:57:50 pm
content: Quote from: Mr Simpleton on April 01, 2014, 07:32:02 pmI think a lot of meters have that "feature". At least I have seen it on some Flukes as well.

author: particleman
author_rank: Regular Contributor
timestamp: April 01, 2014, 10:05:17 pm
content: I have like 10 of those. I wouldnt use them on mains voltage but for working on the car its fine.

author: AG6QR
author_rank: Frequent Contributor
timestamp: April 01, 2014, 10:19:48 pm
content: Quote from: ju1ce on April 01, 2014, 09:57:50 pmI did some testing on my Centech versus my Fluke, looking at exactly this issue. The Centech was far, far worse than the Fluke. In my test, as the battery supply voltage drops, my Fluke 179 stops displaying readings before it can be persuaded to deliver a reading that's out of spec even on the last digit. And I would expect that other Fluke models would always meet their published specs until the battery gets so low that they stop displaying. On the other hand, the Centech continues displaying wrong readings, producing up to a 77% error before it finally shuts down. To be fair, it starts indicating that it has a low battery when it's less than 2% off. But the low battery indication could be a bit cryptic unless you know what to look for.https://www.eevblog.com/forum/testgear/how-bad-can-a-cheap-multimeter-be/The Centech meter designers clearly had the ability to detect a low battery situation. Why did they decide to make the meter continue operating and displaying misleading readings, instead of simply shutting down? In my book, it's better to display nothing than to display readings that are known to be incorrect, but I guess they have a different philosophy.

author: amirm
author_rank: Regular Contributor
timestamp: April 01, 2014, 10:27:12 pm
content: I have a couple of these that I keep in our remote garage and pump house that have no key and hence it could get stolen. Figured any self-respecting thief would leave them and take everything else.Seriously, I have used them a couple of times to check the battery in my lawn equipment. The probes are junk and you have to really poke them to get a reading. But once there and you know what it is supposed to show (!), it works. Well, kind of.Even though they are free, I pass them by and get the free tape measure, flashlights, etc.

author: retiredcaps
author_rank: Super Contributor
timestamp: April 01, 2014, 10:28:13 pm
content: Quote from: AG6QR on April 01, 2014, 10:19:48 pmFrom my own observations, only the newer 17x series (firmware 2.0 or higher) will display "bATT" and stop taking readings when the batteries get low.The 17x series that run firmware 1.x will happily display the low battery icon, but give incorrect readings, generally high.

author: chipwitch
author_rank: Frequent Contributor
timestamp: April 02, 2014, 12:39:33 am
content: Sadly, they're still over-priced.

author: calin
author_rank: Regular Contributor
timestamp: April 02, 2014, 01:40:33 am
content: Ha .. i will get one .. take it apart and try to make use of it as a meter in my diy bench supply. But then again .. it mai be just too crappy

author: PaulAm
author_rank: Frequent Contributor
timestamp: April 02, 2014, 01:43:17 am
content: How to improve the accuracy of the HF Free DMM:1) Remove the free included battery from the free meter2) Drop meter in nearest trash can3) Install battery in Fluke/Beckman/HP/Agilent DMMDon't forget to remove and dispose of battery before it leaks all over your good DMM

author: echen1024
author_rank: Super Contributor
timestamp: April 02, 2014, 01:45:19 am
content: Quote from: PaulAm on April 02, 2014, 01:43:17 amA most excellent idea!

author: kc9qvl
author_rank: Regular Contributor
timestamp: April 02, 2014, 04:01:12 am
content: Sounds like free panel meters.

author: retiredcaps
author_rank: Super Contributor
timestamp: April 02, 2014, 06:15:26 am
content: Accuracy with the cheapest 830 style meters (including the free HF) isn't the problem. Most of them have a +/- 1% on DCV and since most of them are likely based on some sort of 7106 COB, accuracy isn't a problem.The biggest problems with these cheap meters are build quality, reliability and safety.Once you open and see the insides of one, you should be scared to use them on high voltage/current. Due to the shoddy build quality, reliability is justifiably questionable. Split pcbs held together with a blob of solder, cold joints, excess flux, hand soldering, cheap screws, cheap test leads, through hole components bent over instead of using proper smd versions, etc.Almost all these type of meters have no input protection (thermistors, power resistors, varistor) or fuses (not even glass ones). Even experienced users can have an "oops" moment (measuring mains on ohms range, measuring voltage on amps range) and these meters are not likely to survive.If the user understands these limitations, they can be handy in some cases.

author: casinada
author_rank: Frequent Contributor
timestamp: April 02, 2014, 07:09:27 am
content: They're not free unless you live walking distance from themAt $3.5 per gallon + time.....I think I have one of those somewhere.....in the junk bin

author: tjb1
author_rank: Regular Contributor
timestamp: April 02, 2014, 11:27:22 am
content: They always have coupons to get them for free, they also have coupons for the tape measures which are decent.

author: macboy
author_rank: Super Contributor
timestamp: April 02, 2014, 12:01:32 pm
content: Quote from: retiredcaps on April 02, 2014, 06:15:26 amIt is not the survival of the free meter that I would be worried about, but the survival of the user (me). I would never stick such a meter on a high energy circuit (mains, or HV DC) even if I had triple-checked the leads connections and range setting.

author: chipwitch
author_rank: Frequent Contributor
timestamp: April 02, 2014, 12:03:54 pm
content: @tjb1It's true... some of their stuff is decent. Some is to be avoided like the plague. I use their 6" digital calipers extensively. Have 7 or 8 scattered about the shop. Easily accurate to within a couple thousandths of an inch (the all steel ones). Unfortunately, they don't give those away.

author: saturation
author_rank: Super Contributor
timestamp: April 02, 2014, 04:10:04 pm
content: The free measuring tape offer can be more useful.Quote from: SoundTech-LG on April 01, 2014, 07:20:29 pm

author: edavid
author_rank: Super Contributor
timestamp: April 02, 2014, 04:21:41 pm
content: Quote from: kc9qvl on April 02, 2014, 04:01:12 amSince they are 7106 based, you need either an isolated supply or a split supply, so it may not be worth the effort.