Mastech Multimeter Ripoff - Page 1
Forum section: electronics / testgear

author: gridleak
author_rank: Contributor
timestamp: April 06, 2020, 01:47:15 am
content: This is just a warning to members contemplating purchasing one of their "premium" handheld multimeters. Their new generation DMMs are software calibrated. No pots. If you purchase one, and it's out of tolerance, you'll get no help from the manufacturer. I notified them that I have 6 digit calibrators and can do the calibration myself with their software. No luck. They just tell you to send it to one of their "friends" and pay to have the calibration redone for $$$. My Mastech 8218 has always been 1% accurate, when spec is .03%.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 06, 2020, 02:09:36 am
content: Welcome to the club "sarcasm"Paid 160$ cad for a Gossen metrawatt 29s to be software calibrated, the software cost between 1000$ usd and 2000$ usdPaid 150$ cad for an 34401aPaid 75$ usd for 2x Flukes 189And the list goes on and on

author: Electro Detective
author_rank: Super Contributor
timestamp: April 06, 2020, 02:54:21 am
content: Looks like I won't be buying any new meters for a while, especially 'user un-adjustable' types members report about,or till the oldies get un-Cal'dor eaten whole by nasty batteriesstill waiting for the Fluke 87-1, AVOmeter, Fluke 8060A and some 90s vintage Taiwan meters to disagree on measurements.and if they do, I am certain some or all are tweakableand still Y2K ready

author: CDaniel
author_rank: Frequent Contributor
timestamp: April 06, 2020, 11:21:28 am
content: For Fluke and other major brands usually there are calibration procedures in manuals ... of course you have to know what are you doing and have the equipment .For non brands you won't find even the calibration proceduresthats life

author: Fungus
author_rank: Super Contributor
timestamp: April 06, 2020, 11:28:17 am
content: If you open it up there's probably something on the PCB you can short out to go into calibration mode.The exact procedure and voltages required will depend on Mastech though. Maybe somebody here will know.Almost all meters are software calibrated these days because it can be completely automated at the factory. There's nothing wrong with it in principle, these meters are designed not to drift, so...You don't like it? Use it to your advantage - set up your own calibration service with your fancy gear.

author: wraper
author_rank: Unknown
timestamp: April 06, 2020, 11:33:46 am
content: I won't touch pot calibrated multimeters with a ten foot pole because they are unstable crap exactly because of these pots.

author: Fungus
author_rank: Super Contributor
timestamp: April 06, 2020, 11:54:57 am
content: Quote from: wraper on April 06, 2020, 11:33:46 amA million Fluke 8060A owners will disagree with you.

author: exe
author_rank: Unknown
timestamp: April 06, 2020, 12:06:47 pm
content: I have same trouble with cheap aneg meters (though some guys figured out how to do calibration).I think "third-tier" T&M manufacturers try go the route of more established brands to increase their profit margins. That's unfortunate for me as a buyer.Another problem I found is that many calibration facilities don't deal with individuals.

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: April 06, 2020, 03:23:34 pm
content: I agree, outside of Fluke and may be Keysight, very few manufacturer provide calibration procedures. I think the reason is two folds, one is to drive profit for their calibration partners/dealer network due to the thin margin, the second is to prevent inexperienced users from messing up their meters, either by user mistakes, or more likely, by out-of-calibration or inadequate calibrators. I have seen videos out there coaching people to calibrate with a battery and assume its voltage from the spec sheet. So I can see their reason to keep it a secret to reduce warranty claims.It is not ideal, but if you like to tinker with calibration, you should assume that vast majority of the B-Brand meters does not have a service or calibration manual. And you should do the due diligence before buying it.

author: MadTux
author_rank: Frequent Contributor
timestamp: April 07, 2020, 12:39:28 am
content: That's why I love my HP-3456As, no custom parts, nice calibration pots for each range and usually better specs than the average 1-2k$ DMM nowadays.Apart from that, if I can't calibrate a DMM myself because I don't have the tools, who cares. It just goes uncalibrated, better than getting ripped off. Usually, a good DMM stays within spec for much longer than the suggested calibration interval. And I won't even touch anything without open calibration procedures, so screw you, Rigol and Chinesium crap friends...Also with 99% of the things I do, the exact value is quite irrelevant. Fast reading/response, high resolution, good linearity&precision, along with good display and user interface are more important for me, than ppm accurate readings.Like who cares, if the 15V rail is 15.001V or 15.002V, I want to know wether there is noise in mV range.Or for checking shunt resistors or power Mosfet RDSon, I need a DMM with high resolution in mV range, accuracy isn't that important, as long as it's like 0.1%