Any cheap 5.5 or 6.5 digit bench top DMMs out there? - Page 1
Forum section: electronics / testgear

author: jbuszkie
author_rank: Newbie
timestamp: December 13, 2021, 04:34:59 pm
content: I want to pick up a decent bench top DMM on the cheap. Like the bench DMM equivalent of our Rigol DS1054 scope! :-)I'd like 5.5 or 6.5 digit.. Used is fine. Is my best best something like the agilent 34401A on ebay hoping for a great deal?I'd like to spend under $300...Thanks,Jim

author: jbuszkie
author_rank: Newbie
timestamp: December 13, 2021, 04:53:24 pm
content: And the only real requirement is 4W resistance...

author: bdunham7
author_rank: Super Contributor
timestamp: December 13, 2021, 05:00:10 pm
content: Beware of deals, prices on that stuff is at an all time high right now. A 34401A used to be a relative bargain, but now broken ones with no bumpers or handle will fetch over $300. The later Aglilent-branded units are $600 or so.Going older has its risks if you just want a working DMM and not a repair project. The Fluke 8840 and similar also used to be bargains, but there's a lot of rough ones out there. You can probably sill get a decent one for under $300 if you look. You're just a few years late!

author: jbuszkie
author_rank: Newbie
timestamp: December 13, 2021, 05:04:32 pm
content: Quote from: bdunham7 on December 13, 2021, 05:00:10 pmD'oh!I'm not in a rush.. *sigh* looks like I might have to spend more than I wanted...

author: Algoma
author_rank: Frequent Contributor
timestamp: December 13, 2021, 05:20:41 pm
content: I went with a new Siglent SDM3055. The cost of good condition used units has already risen enough to overlap with the price of new Siglent or Rigol units. There isn't much savings anymore going with the used market when you can get a warrenty and extra features too, for basically the same price...

author: hgl
author_rank: Regular Contributor
timestamp: December 13, 2021, 05:25:47 pm
content: For under $ 300 you can get an HP E1412A 6.5 digits, but it's not a desktop device. You also need a VXI rack and a controller and are back over it.

author: TurboTom
author_rank: Super Contributor
timestamp: December 13, 2021, 05:50:16 pm
content: If you don't mind the "Red LED Charme" and the ugly enclosure, the Keithley 196 may be an instrument to fit your box. Four wire resistance, lightning-fast auto range and full screen count of +-3,000,000. On the minus side, its maximum voltage range is 300V, the high input impedance (>>10MOhm) is limited up to the 3V range and there's no capacitance or diode test. Keithley uses a selected LM399 as a reference and a special dual slope / charge balance ADC approach, constructed of individual components. Everything's very repairable and good documentation is available. Sometimes, these meters can be found for as little as 150 USD. You should be prepared to pay for a recalibration (if you cannot do it yourself and if the meters have been messed with) though the original calibration appears to hold quite well over the time.Good luck!

author: AVGresponding
author_rank: Super Contributor
timestamp: December 13, 2021, 05:54:39 pm
content: Those old brown boxes are pretty damn good.Also consider an HP 3478, LCD so fewer worries about display death, likewise Keithley 197/A.

author: tooki
author_rank: Super Contributor
timestamp: December 13, 2021, 06:16:15 pm
content: If you don’t need the high speed of modern bench DMMs, a Keithley 197 or 197A will work nicely, as AVGresponding also said. (They’re 3 readings per second, like a typical handheld multimeter.) Something I really like about them is that they automatically switch between 2W and 4W resistance.

author: GerryR
author_rank: Frequent Contributor
timestamp: December 13, 2021, 06:43:04 pm
content: The Fluke 8810A, 5-1/2 digit, 4-wire ohms, AC True RMS. You have to be careful when purchasing as the basic meter is only DC volts and everything else an option, so you have to make sure all the options you need are included. Good meter and documentation is readily available, schematics as well.

author: jbuszkie
author_rank: Newbie
timestamp: December 13, 2021, 06:55:00 pm
content: Quote from: GerryR on December 13, 2021, 06:43:04 pmWow that one is old school!! :-)

author: J-R
author_rank: Super Contributor
timestamp: December 13, 2021, 07:42:45 pm
content: I have the Fluke 8840A and Keithley 197A and like them both. The best deals are found when you read the tea leaves and make a good guess why it's being sold for "parts". I got both relatively recently for around $100ea and the fixes were trivial. But I think you could also get either in fully working condition for under your budget.As an aside, I think 4-wire can be an over-rated feature. It's trivial to just use a power supply and the mV scale on your DMM to obtain similar results as I showed here:https://www.eevblog.com/forum/testgear/the-best-accurate-low-ohm-meter-possible/msg3681376/#msg3681376

author: GreggD
author_rank: Regular Contributor
timestamp: December 13, 2021, 08:06:32 pm
content: I got a HP-34401 a month ago from Ebay, works, good display.$275 +$18-tax free shippingNo cal sticker.

author: JohanH
author_rank: Frequent Contributor
timestamp: December 13, 2021, 08:42:39 pm
content: Quote from: GreggD on December 13, 2021, 08:06:32 pmI paid almost twice as much in EU for an Agilent 34401A, seems to be a 2002 model from the cal data. And then ended up buying a new front panel, bumpers, handle and some other stuff, because I wasn't happy with the worn looks.If you can get a cheap deal as GreggD, I certainly recommend it. Otherwise look for a newer 5 ½ meter and you will get more features.The 4W ohms is overrated on these older meters anyway. If you really need 4W measurement, that's the area for milliohm meters. I built one based on the Scullcom/Barbouri design.

author: J-R
author_rank: Super Contributor
timestamp: December 13, 2021, 09:41:58 pm
content: I'm of the opinion that if you're going to get a 5.5 digit and above DMM, you should have it calibrated and obtain the data or at least have some other method to verify its performance.

author: GerryR
author_rank: Frequent Contributor
timestamp: December 13, 2021, 10:43:31 pm
content: Quote from: jbuszkie on December 13, 2021, 06:55:00 pmOldie but a Goodie!!

author: ogden
author_rank: Super Contributor
timestamp: December 13, 2021, 10:52:07 pm
content: Quote from: jukk on December 13, 2021, 08:42:39 pmAre you sure that milliohm meter built using eBay "2 Volt full scale meter" not even having any precision specs is better that Agilent 34401A?

author: duckduck
author_rank: Frequent Contributor
timestamp: December 14, 2021, 12:28:24 am
content: Quote from: jbuszkie on December 13, 2021, 04:34:59 pmI like my GW Instek GDM-8251A. I think they are from 2010. You can find them used for around USD250. I bought mine because it has a lot of connection options for automation. Autorange is a little slow, but not bad. I also have a Keithley 197A that I got off of Craigslist for stupid cheap (USD15). You can also find an old HP 3455A for cheap (got mine for USD60), but they have a fan and that can be annoying. All of those do 4 wire resistance measurements.https://www.gwinstek.com/en-IN/products/detail/GDM-8251AEDIT:The Instek is the cheapest 5 1/2 digit meter with USB that is supported by sigrok (https://sigrok.org/wiki/GW_Instek_GDM-8251A).

author: edavid
author_rank: Super Contributor
timestamp: December 14, 2021, 01:27:23 am
content: Quote from: duckduck on December 14, 2021, 12:28:24 amIs a service manual available?

author: dorkshoei
author_rank: Frequent Contributor
timestamp: December 14, 2021, 01:34:36 am
content: Quote from: bdunham7 on December 13, 2021, 05:00:10 pmI have a very nice condition. 34401a witg rev 2 display. Bumpers, handle. $325 plus shipping No formal Cal but ive tested with voltage reference and calibration resistors. Cash sale.

author: duckduck
author_rank: Frequent Contributor
timestamp: December 14, 2021, 05:23:58 am
content: Quote from: edavid on December 14, 2021, 01:27:23 amI couldn't find one. Couldn't find schematics either. I hope it doesn't break

author: Andrew_Debbie
author_rank: Frequent Contributor
timestamp: December 14, 2021, 09:42:51 am
content: Quote from: jbuszkie on December 13, 2021, 04:34:59 pmA few others to consider:Aim TTi 1906 Made in UK. 5 1/2 digit 210,000 count.Aim TTi 1908 5 1/2 Digit - Made in UK. £475/$600 new. Used ones sometimes show up at reasonable prices.https://www.aimtti.com/product-category/legacy-products/aim-1906https://www.aimtti.com/product-category/multimeters/aim-1908I have a Dana 5100. Built in California in the late 1970s. The specifications are amazing considering how old it is. I paid £25 for mine with a faulty digitizer card, which I fixed.. The manual is comprehensive. Good meter when it works. Too early to say if it will be reliable enough for regular use. They all do AC but True RMS AC was an option.The 5100AF variant turns up on US eBay often enough. Perhaps a batch of them came out of Navy surplus fairly recently? The AF has double the sampling rate of the 5100, but perhaps not the same accuracy? I'd have to check.Other Dana and Racal Dana meters turn up on eBay all the time.The 5900 is a 19" rack sized meter that is similar to the 5100 but with more slots for option cards.Racal/Dana 6000 series meters have averaging, min, max and very good specifications. I've never been inside a 6000 and can't comment on reparability.Dana 5100 specs. The 5100AF and 5900 are similar. The 5100 is 199,999 the 5900 is 160,000.

author: JohanH
author_rank: Frequent Contributor
timestamp: December 14, 2021, 11:26:12 am
content: Quote from: ogden on December 13, 2021, 10:52:07 pmNo, I'm not claiming it to have better precision specs.It's just nice to have a dedicated instrument. I can also hook up the Agilent as an external voltmeter display.

author: JohanH
author_rank: Frequent Contributor
timestamp: December 14, 2021, 11:41:18 am
content: Quote from: duckduck on December 14, 2021, 12:28:24 amI also have a GW Instek GDM-8251A. In comparison with the 34401A it has 10A range, temperature and dual display. But it doesn't really do well in sub 1 ohm measurement, at least the meter I have. Here the 34401A is better.

author: Jester
author_rank: Frequent Contributor
timestamp: December 14, 2021, 06:10:41 pm
content: Quote from: jukk on December 14, 2021, 11:41:18 amI had a GDM-8251, I ended up selling it, it’s an okay bench meter but I would spend a bit more for a 34401A. I have several bench meters and I would use the GDM only when all the others were already in use.

author: AVGresponding
author_rank: Super Contributor
timestamp: December 14, 2021, 06:29:57 pm
content: The price you pay depends a lot on where you are, patience, and luck.My Fluke 8840A was just under £100 shipped, haven't seen one for less than half again that much since. My Agilent 34401A (round power button) was a little over £300 shipped, well below the normal prices. I got a Keithley 2000 for £250 shipped because it had a fault I recognised the symptoms of (dirty front-rear switch), but I had to pay well over £400 for my Keithley 2015. My TTi 1906 was around £60 shipped, very good value imo.As for older units keeping their accuracy, I've a couple of Fluke 8300A's (only one with ohms/mV option unfortunately) which are beautiful to look at, and still dead-on accurate compared to an in-cal modern meter, pretty good going for something so ancient.EDIT: HP stuff especially seems cheap and plentiful in the US compared with over here:https://www.ebay.com/itm/203751857114

author: med6753
author_rank: Super Contributor
timestamp: December 15, 2021, 02:43:16 am
content: As previously mentioned Fluke 8800A/8810A series. Just make sure it has the Ohms/AC options installed. And you should replace the electrolytic capacitors in PSU as they have a tendency to short.Sometimes come up on Ebay for as little as $100 USD.

author: duckduck
author_rank: Frequent Contributor
timestamp: December 17, 2021, 11:41:39 pm
content: Quote from: AVGresponding on December 14, 2021, 06:29:57 pmYeah, they pretty much give away hp 3478As on ebay in the USA. You can easily get one for around USD100, delivered. Nice meters. Made in the USA. They only go up to 300V, which is why I sold mine.