Greenlee DM-860 aka Brymen 859 teardown - Page 1
Forum section: electronics / testgear

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 28, 2014, 07:08:56 am
content: So I just picked up a Greenlee DM-860-C on eBay recently and it came in today. So of course what do we do here? Open it up! This meter is designed by Brymen and is the Brymen 859. It's also known as the Extech MM570A.The meter came in this handy case.The contents are: the multimeter, the probes (feel only slightly better than the ones that come with the ut61e), optically isolated rs232 cable, the manual (with a bit of water damage) and a baggy with the software, thermocouple and spare 1A fuseThis bad boy is large. This is it next to a Fluke 83V.Why yes that's 5.5 digits (500k counts) of D.C. voltage goodness.Some relevant details. High breakage current fuses, 1000V CAT III, DC+AC True up to 100kHz. The rubber case has a very different feel from the rubber fluke cases. It has a rougher more rugged feel.The back is held on by four self-tappers. Each screw has a rubber o-ring for water resistance.Here we can see the input protection. At least a few fusible resistors, two spark gaps and two HRC fuses. Loads of notches, cutouts abd separators to keep various signal paths isolated.This screw holds the board in case (the top is held down by a lip). Notice the o-rings around the sockets. These mate with the case to provide water resistance I guess.Main ICs, two oscillators and a resonator, the true rms ic and the REF 43G voltage reference.This thing seems solidly built and appears to be water resistant.A few other things of note.If you try to measure voltage with the probes the current measurement spots. It beeps very loudly at you and displays the above warning.It can measure dBm with a wide variety of input impedances (some standard, some not so standard).Also it remembers the setting for each spot on the dial. So if you set the DCV setting to AC+DC, then it will still be AC+DC when you go back to it, even through power cycles.Lastly, it has two off positions. One near the voltage section, the other by the amperage section.In conclusion, all in all a damn solid meter. I'm quite impressed with it.Sent from my EVO using Tapatalk

author: retiredcaps
author_rank: Super Contributor
timestamp: January 28, 2014, 08:19:23 am
content: Quote from: PedroDaGr8 on January 28, 2014, 07:08:56 amThanks for the internals pics.Are you still on the hunt for more meters on ebay?

author: Wytnucls
author_rank: Super Contributor
timestamp: January 28, 2014, 10:54:59 am
content: The backlight is notoriously bad and the 500,000 count is just high res, no better accuracy than 50,000. Apart from that, a solid meter with a good set of features.

author: BravoV
author_rank: Super Contributor
timestamp: January 28, 2014, 10:59:08 am
content: Thanks for the pics !Quote from: Wytnucls on January 28, 2014, 10:54:59 amWhat VRef chip it uses ?

author: Wytnucls
author_rank: Super Contributor
timestamp: January 28, 2014, 11:15:51 am
content: I don't think it has an external voltage reference. Best accuracy is quoted as 0.02%+2d.Actually, it has an external 2.5V reference, visible behind the true RMS converter can, on one of the picture.http://www-inst.eecs.berkeley.edu/~cs150/Documents/ADREF43.pdf

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: January 28, 2014, 05:07:55 pm
content: These jumped out at me. Water damaged manual (you noted), the rubber case doesn't fit well, it leaves bottom-left, bottom-right, edges exposed. Murphy will ensure that it impacts the floor there.Don't like that style of probe.Is that a piece of paper along the right-hand side with foil stuck on?Is that a floppy disk? What the??I like that it has pc interface and cable and a nice case.Nice pics!

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 28, 2014, 07:35:03 pm
content: Quote from: retiredcaps on January 28, 2014, 08:19:23 amAnything I think I can cleanup and flip for a profit. Since my wife and I split last year, just trying to supplement my income any way I can. Get a bit of extra spending/travel money.Quote from: Wytnucls on January 28, 2014, 10:54:59 amThe backlight and the probes are two very disappointing things about this meter. The backlight is worse than the fluke 116 I use at work. Super dim.Quote from: GiskardReventlov on January 28, 2014, 05:07:55 pmThe water damage on the manual doesn't worry me. Like I indicated in the post, the meter has a degree of water resistance to it. On top of that nothing else shows signs of water. So my guess is someone left the manual out and spilled something on it. I'm just surprised to get the manual at all. Most people lose these things.Part of the problem with that is that I half-assed putting it in the rubber.The bumper is REALLY thick, much thicker than a fluke bumper (that can be good or bad). I'll try to take an image to show it. I doubt it could hit on that corner easily.Floppy because this meter is from around 2000. Back then a floppy was reasonable. My bet is they ship with a CD now.No that is a piece of plastic with foil attached. You can see it in this image.

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: January 28, 2014, 08:08:10 pm
content: I didn't know that it was an older meter. Significant fact. Ballpark price?The cable then is just a serial cable?

author: rsjsouza
author_rank: Super Contributor
timestamp: January 28, 2014, 08:45:42 pm
content: Quote from: GiskardReventlov on January 28, 2014, 08:08:10 pmThe cable has some intelligence to it. Checkthis attemptto create one.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 28, 2014, 08:51:12 pm
content: Quote from: GiskardReventlov on January 28, 2014, 08:08:10 pmThe extech MM570A goes for $330 new. The Brymen branded 859 sells for ~$240-260 shipped new. The Brymen comes with only the meter, probes and thermocouple. The data cable appears to be a bidirectional optically isolated serial cable (it runs about $50 and is sold separately). So I'd say for a used one the price range of $150-200 is reasonable if it includes ALL of the mentioned parts.

author: Mr Simpleton
author_rank: Unknown
timestamp: January 28, 2014, 09:09:55 pm
content: Quote from: rsjsouza on January 28, 2014, 08:45:42 pmOr check these guys...https://www.eevblog.com/forum/testgear/brymen-ir-connection-protocol-anyone-sniffed-it-yet/msg302326/#msg302326