I just bought a Data Precision 2480R Bench DMM - Page 1
Forum section: electronics / testgear

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 09, 2013, 02:35:27 am
content: I was doing some hunting on eBay and I couldn't resist picking up my very first Bench DMM for only $20 on eBay!I've been looking around a bit lately and I established that most of the bench DMM's are at least $30 usually, and those are for 3.5 digit meters. So I couldn't help myself when I saw this 4.5 digit meter for only $20.Does anyone know anything about this meter (Data Precision 2480R) or even the Data Precision name itself?Here's a picture of the thing (not my picture)One thing I can already see is that these plugs are not going to accept the banana jacks with the long covers over them, but that doesn't really bother me.Thanks!

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 03:36:23 am
content: Quote from: EpicIntelGamer on August 09, 2013, 02:35:27 amI will refer you to this fine post on that topic:Quote from: free_electron on August 07, 2013, 04:20:56 amAnd the solution for the problem:

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 03:40:48 am
content: The manual isn't quite as easy to find as some.... I've had enough coffee to be generous, soI found it.Calibration info is in there. Seems to be a bit short on full schematics, though it does have a good bit of theory-of-operation stuff.Specs look decent, definitely good for $30. Is it still accurate?

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 09, 2013, 03:42:50 am
content: Quote from: c4757p on August 09, 2013, 03:36:23 amOh so that's a good thing then? Like I said, personally, I feel fine without it.Sounds like a good solution as well!And I notice in the thread where free_electron posted he said he doesn't care about HV but really I think I could easily get away with sticking 1KV in some non shrouded leads just because of the massive distance between the two leads. Not that I have anything that will really output 1KV.Thanks!

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 09, 2013, 03:45:52 am
content: Quote from: c4757p on August 09, 2013, 03:40:48 amOh hey thanks again! Very nice of you to dig that up for me, much appreciated!I'm not sure if it's accurate. I bought it "working" and its still on its way. The problem is, my only other DMM is a TERRIBLE 3.5digit, so I can't even see if this meter is accurate or not.

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 03:46:42 am
content: They're just a pain in the ass, useless and annoying. There's no particular advantage to not having them other than... not having them. IMHO safety shrouds on a bench multimeter is a bit like wearing a helmet and knee pads while driving a car.

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 09, 2013, 03:48:50 am
content: Quote from: c4757p on August 09, 2013, 03:46:42 amYeah I can see their use on smaller DMM's where the jacks are pretty close to eachother and your hands are very close to the jacks but on a bench DMM (especially mine) there is a fair bit of distance between the two jacks and your hands usually wont be as close to the jacks as they would on a handheld DMM.

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 03:51:51 am
content: It's probably fine. I buy and fix old DMMs all the time, and the only ones I ever see that aresorelyin need of an adjustment are the broken ones.Just do a few sanity checks. Check one somewhat-known voltage absolutely (like a fresh 9V battery or something, though I can't remember off the top of my head what the "exact" initial voltage should be) to make sure it's not hilariously off the mark. Then pick a voltage that is high for each range, and compare the reading between each range and the next to check the per-range adjustments. (Obviously the 1000V range might be a bit tricky!) Check some 1% resistors. Use a power supply and a resistor to make a rough current source, check the current ranges. All you really need to do is make sure nobody let their dog tweak the trimpots.Quote from: EpicIntelGamer on August 09, 2013, 03:48:50 amStandard is 0.75 inch / 19.05mm between pairs of jacks and the vast majority conform to this...

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 09, 2013, 03:55:09 am
content: Quote from: c4757p on August 09, 2013, 03:51:51 amOh maybe this would be a good time to use my little REF02 sanity check 5V reference!The closest thing I have to 1000v is the 600v output of a transformer for a tube radio I'm working on.Unfortunately I have no 1% resistorsThe thing is though especially with current, I'm not sure if I can actually tell if the bench dmm is accurate because especially on amps my handheld meter is horrible.And also maybe I'm looking at the picture wrong but It looks like more than 3/4in between those jacks.

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 03:59:09 am
content: Just test the mA ranges. What is the highest reasonably accurate voltage you have? 50V across a 10k resistor is 5mA, and 10k is high enough that the burden voltage offset will not be too high. You can even measure it and compensate for it in your calculations. If you don't have such a high voltage you can use a lower one, you'll just need to measure the current shunt resistor and compensate for it. (You can use the meter to measure its own shunt. I see it uses shared jacks, so you can't do the "bridge ohms and amps" trick, but you can slide the case open and probe it. Just don't connect ground.)Calculatethe current, don't measure it. Screw the A ranges, who the hell needs precision above 100mA anyway....?The spacing looks proper to me.... Of course, I can't estimate small distances in inches for shit, but it does look like about 20mm...

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 09, 2013, 04:07:43 am
content: Quote from: c4757p on August 09, 2013, 03:59:09 amI'm not sure what you define reasonably accurate. I have a variac and some 600v diodes and a 600v transformer so tecnhically I can get some pretty high VDC but I'm not sure if it has the accuracy you'd want.Other than that I have a hacked 7805 that can output up to 15v, that's about it. I'm nervous about all of this resistor business, I don't really ever go about using them for anything precise or with current.And as for your last statement of that paragraph, *raises hand* "uhh......I.........I.....do..." lolMost of the current ranges I ever measure are up in the amps, though now if I have the capability for mA, I guess I'll start using it more often.Hmm, I'm the opposite, can't estimate meteric even a quarter as precise as I can in imperial, and even that I'm not too good with.

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 04:11:07 am
content: Depends on how accurately you want to check it! Like I said, you just need to make sure nobody let their dog tweak the trimmers.No..... keep off the 600V, no need to fart around with that. I thought 50V because that what my highest-voltage "low voltage" PSU goes up to. Just use what you have and let Ohm's Law do the rest.Ha... I was kidding, after all, on my bench anything over about an amp is "oh shit, something's about to fry"...I can't estimate large things in metric and can't estimate short things in imperial! After getting used to working with PCB layouts I can even do a decent job estimating widths to the tenth-millimeter... But meters? Kilometers? Kilograms? Kiloanythings, really? Nope, I'm hopeless.

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 09, 2013, 04:15:43 am
content: Quote from: c4757p on August 09, 2013, 04:11:07 amAw I knew one of these days I'd be forced to learn about ohm's law, I guess that day is quite soon now.Think I might just hook it up to 600V just to see how accurate it is with probably the highest voltage I'll ever need to measure.Usually the only thing I measure are motors and other big things I'm working on, but I suppose I'll start to measure mA consumption of some of my circuits just out of curiosity.Later this month I plan to spend $100 to $150 on a really nice used Fluke portable DMM so maybe then I'll have something that is accurate and help me make this bench dmm accurate.I barely know meteric in general, and many imperial sizes confuse me. The only ones I've definitely got down is weight and distance measurement in imperial.

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 04:19:47 am
content: Ohm's law is... well, it's Ohm's law...That's it. It's about the most important "law" you'll learn in electronics, behind maybe Kirchhoff's laws - get familiar with it!

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 09, 2013, 05:15:11 am
content: Quote from: c4757p on August 09, 2013, 04:19:47 amThat's not so bad, and will probably come in handy.All I know about Kirchoff's law is that current will flow equally along two wires or something like that.

author: Bored@Work
author_rank: Super Contributor
timestamp: August 09, 2013, 06:10:53 am
content: Quote from: EpicIntelGamer on August 09, 2013, 05:15:11 am

author: IonizedGears
author_rank: Regular Contributor
timestamp: August 09, 2013, 07:09:53 am
content: Kirchhoffs law is of voltage and current. The voltage law basically states that all the voltage drops in a circuit is equal to the applied or source voltage. Kirchhoffs current law states that current through one node is equal to the sum of the branches of said node. Hard to explain without a diagram.

author: steve30
author_rank: Frequent Contributor
timestamp: August 09, 2013, 07:24:53 am
content: Looks like a nice multimeter.We had a handful of old Data Precision meters at my old college, but they weren't in use as we had some more modern 1980s/1990s era meters. Some were LED and some were Nixie tube.

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: August 09, 2013, 01:45:35 pm
content: Quote from: EpicIntelGamer on August 09, 2013, 05:15:11 amOhm's Law isn't handy – it's pretty much essential.even if all you're doing is lighting up an LED, you need to understand and be able to use Ohm's Law.Just remember the first form – V = IR – and the rest is trivial algebra.

author: ddavidebor
author_rank: Super Contributor
timestamp: August 09, 2013, 02:45:58 pm
content: Quote from: IonizedGears on August 09, 2013, 07:09:53 amFirst law: you eat what you cookSecond laws: what come in will exit

author: Bored@Work
author_rank: Super Contributor
timestamp: August 09, 2013, 05:19:40 pm
content: Quote from: IonizedGears on August 09, 2013, 07:09:53 amOh dear, oh dear, oh dearThe sum of all the voltages around a loop is equal to zero.

author: IonizedGears
author_rank: Regular Contributor
timestamp: August 09, 2013, 06:14:39 pm
content: No, the sum of all the voltage drops in a loop minus the applied or source voltage =0.

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 06:29:39 pm
content: Oh dear, oh dear.No need to count the source twice. Sources aren't special objects, they're all voltage drops.If you subtract the "source voltage", that method cannot cope with multiple sources, especially ones external to the loop, which doesnothave to exist in isolation for KVL to work.Example where that method fails (your money refunded 100% if my math is wrong):

author: IonizedGears
author_rank: Regular Contributor
timestamp: August 09, 2013, 06:50:53 pm
content: :/ that isn't what they taught me in school

author: Bored@Work
author_rank: Super Contributor
timestamp: August 09, 2013, 06:51:34 pm
content: Quote from: IonizedGears on August 09, 2013, 06:14:39 pmSeriously, don't they even teach Kirchhoffs laws properly these days? Because what you wrote - twice - is utter bullshit. Twice.

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 06:53:26 pm
content: Quote from: IonizedGears on August 09, 2013, 06:50:53 pmThey oversimplified it because in all of the example problemsthey would ever give youit would work, and they wanted to treat you like a moron, which is fun. They don't give a shit if it leaves you unprepared to deal withrealproblems.This is, at least, my experience.

author: IonizedGears
author_rank: Regular Contributor
timestamp: August 09, 2013, 06:58:15 pm
content: Could you point me towards the direction in which I could look up more on this method?

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 07:03:00 pm
content: It really is just common sense! If you pick a point and go around a full circle back to that point, you have to get back where you started, right? So for every volt you gain, you must lose one somewhere else in the same circle.

author: IonizedGears
author_rank: Regular Contributor
timestamp: August 09, 2013, 07:05:45 pm
content: Okay, that sentence is really all I needed.

author: c4757p
author_rank: Super Contributor
timestamp: August 09, 2013, 07:10:42 pm
content: Likewise, short of the "something" being a magical electron eater, every charge unit into something must exit it, since you can't create or destroy them. This is Kirchhoff's current law. What goes in must come out, or in other words, the sum of all currents entering a point (wherepositive currents leavingare equivalent tonegative currents entering) is zero.I've found that students often see this as unintuitive in the case of a charging capacitor, where they think that charge should enter one side, but not exit the other, because they imagine it like a "charge tank". The symmetry between "positive currents leaving" and "negative currents entering" shows why even this case will be symmetric, with charge moving in one side and out the other: the positive side charging to become more positive is the exact same thing as the negative side charging to become more negative.

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 10, 2013, 01:10:15 am
content: Think I'm more confused than ever now lolAnyways, I put in a best offer to try to get a second identical meter from the same seller for the same price as before ($20) hopefully I can get it!!

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 15, 2013, 04:13:58 am
content: I did not get the second but I might later.I did however receive the one I did order!The faceplate was held on from the factory with two little strips of 30some year old double sided tape and was almost fallen off so I hot glued it back on.Other than that I only powered it up and tested out the 10VDC range with my REF02 .3% 5VDC Voltage Reference (here's a thread about it:https://www.eevblog.com/forum/projects/simple-voltage-reference-idea/) and it tells me that it is 5.009VDC which is probably correct (but I have nothing more accurate to check it against).I'll check some of the other functions and ranges tomorrow if I get a chance, but for now at least we know it works and its readings are reasonable.

author: MatCat
author_rank: Frequent Contributor
timestamp: May 04, 2014, 06:39:05 pm
content: How has it been treating you? I just picked one up on ebay for $0.99 + $15 shipping, hopefully it comes out good

author: MatCat
author_rank: Frequent Contributor
timestamp: May 07, 2014, 09:17:05 pm
content: Got mine in today, and I am pretty happy! The only thing accurate I had access to was a good resistor box, I tested between 0.01% to 0.5% of the value, which I am sure is down to the resistors in the box.

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: July 31, 2015, 05:48:49 pm
content: Sorry to dig up an old thread, especially one that went crazy off topic to begin with, but I will bring it back to the initial topic:I got one of these Data Precision 2480R meters recently. It has an issue where DCV at the 100v setting shows the wrong value. Interestingly (since the attenuator resistors for the different scales seem to be in series with one another), the other ranges work fine. I believe all the kOhm ranges work correctly too.Does anyone have a schematic for this? I only find them for sale on eBay for the usual Tucker Electronics high prices.... More than the cost of the meter.In trying to diagnose this I find a TP by the attenuator resistors that measures around 91k ohms on all other ranges, but 62k ohms when you push the 100v switch. This is pretty proportional to the increase in displayed voltage. I can measure the voltage on the switch (which is one of those mult-contact push buttons with the physical lockout of other switches) and it is equal to the voltage displayed. It is just wrong.I am wondering if perhaps it is the switch itself. I sprayed contact cleaner in there as well as I could. I may try shorting the contacts on the switch manually. However, I am thinking the issue may be further up the line, as this is a decrease in resistance to ground, which makes me think it is more of a mild short, or failed part. Without the schematic it is hard to trace where things go, especially since I don't know precisely how those switches work in the first place (what contacts are being opened and close by the switch).Any help would be appreciated... Thanks!

author: IanR
author_rank: Newbie
timestamp: June 19, 2024, 06:16:08 am
content: Hi There,Did you ever get a schematic for a Data Precision 2480R? I just got me one of those meters and would like a schematic if you have one please.... Cheers, Ian