But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter. The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it's just same design with new label, when they got enough reports/complaints. I am wondering if it's worth picking up some of the older 1000V models off ebay.
HV damages meter?
Started by ●December 31, 2022
Reply by ●December 31, 20222022-12-31
On Sat, 31 Dec 2022 10:19:53 -0800 (PST), Ed Lee <edward.ming.lee@gmail.com> wrote:>But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter. > >The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it's just same design with new label, when they got enough reports/complaints. > >I am wondering if it's worth picking up some of the older 1000V models off ebay.Buy Fluke, or at least Extech.
Reply by ●December 31, 20222022-12-31
On Saturday, 31 December 2022 at 19:30:29 UTC, John Larkin wrote:> On Sat, 31 Dec 2022 10:19:53 -0800 (PST), Ed Lee > <edward....@gmail.com> wrote: > > >But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter. > > > >The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it's just same design with new label, when they got enough reports/complaints. > > > >I am wondering if it's worth picking up some of the older 1000V models off ebay. > Buy Fluke, or at least Extech.Fluke aren't perfect. I once accidentally touched the anode of a TV line output valve (tube) when testing with a Fluke meter. It killed the LED display. John
Reply by ●December 31, 20222022-12-31
On a sunny day (Sat, 31 Dec 2022 11:30:18 -0800) it happened John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in <an21rhpe3mkic8q9a4p070i14lkm7v5eas@4ax.com>:>On Sat, 31 Dec 2022 10:19:53 -0800 (PST), Ed Lee ><edward.ming.lee@gmail.com> wrote: > >>But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the >>meter. >> >>The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. >>Perhaps it's just same design with new label, when they got enough reports/complaints. >> >>I am wondering if it's worth picking up some of the older 1000V models off ebay. > >Buy Fluke, or at least Extech.On recommendation of somebody here I bought 4 multimeters on ebay for the amount of 4$something a piece. All 4 are still working... http://panteltje.com/pub/chinese_multimeter_img_3159.jpg Used everyday! Quite accurate. too. Guess I was lucky.
Reply by ●December 31, 20222022-12-31
On a sunny day (Sat, 31 Dec 2022 12:49:05 -0800 (PST)) it happened John Walliker <jrwalliker@gmail.com> wrote in <7c4aebc5-150c-4081-963c-f438d19a0ff6n@googlegroups.com>:>On Saturday, 31 December 2022 at 19:30:29 UTC, John Larkin wrote: >> On Sat, 31 Dec 2022 10:19:53 -0800 (PST), Ed Lee >> <edward....@gmail.com> wrote: >> >> >But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the >> >meter. >> > >> >The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. >> >Perhaps it's just same design with new label, when they got enough reports/complaints. >> > >> >I am wondering if it's worth picking up some of the older 1000V models off ebay. >> Buy Fluke, or at least Extech. > >Fluke aren't perfect. I once accidentally touched the anode of a TV line output valve (tube) >when testing with a Fluke meter. It killed the LED display. > >JohnI once did that with my scope probe. Called the importer, got a new input chip, fixed it..
Reply by ●December 31, 20222022-12-31
On Saturday, December 31, 2022 at 2:14:26 PM UTC-8, Jan Panteltje wrote:> On a sunny day (Sat, 31 Dec 2022 11:30:18 -0800) it happened John Larkin > <jla...@highlandSNIPMEtechnology.com> wrote in > <an21rhpe3mkic8q9a...@4ax.com>: > >On Sat, 31 Dec 2022 10:19:53 -0800 (PST), Ed Lee > ><edward....@gmail.com> wrote: > > > >>But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the > >>meter. > >> > >>The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. > >>Perhaps it's just same design with new label, when they got enough reports/complaints. > >> > >>I am wondering if it's worth picking up some of the older 1000V models off ebay. > > > >Buy Fluke, or at least Extech. > On recommendation of somebody here I bought 4 multimeters on ebay > for the amount of 4$something a piece. > All 4 are still working... > http://panteltje.com/pub/chinese_multimeter_img_3159.jpg > > Used everyday! > > Quite accurate. too. > > Guess I was lucky.Did you try them with 400V?
Reply by ●December 31, 20222022-12-31
On Saturday, December 31, 2022 at 12:19:58 PM UTC-6, Ed Lee wrote:> But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter. > > The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it's just same design with new label, when they got enough reports/complaints. > > I am wondering if it's worth picking up some of the older 1000V models off ebay.I used a Fluke 83 when I was earning my keep. It survived sitting in a pickup year around in Nebraska weather and trips through wet cornfields. I might've left it set on ohms while checking a 480 volt circuit but I don't remember. I think it survived that also. Is Triplett any good nowadays?
Reply by ●January 1, 20232023-01-01
On a sunny day (Sat, 31 Dec 2022 15:19:07 -0800 (PST)) it happened Ed Lee <edward.ming.lee@gmail.com> wrote in <54f455e1-bf20-44ab-a3e8-268d2251effen@googlegroups.com>:>On Saturday, December 31, 2022 at 2:14:26 PM UTC-8, Jan Panteltje wrote: >> On a sunny day (Sat, 31 Dec 2022 11:30:18 -0800) it happened John Larkin >> <jla...@highlandSNIPMEtechnology.com> wrote in >> <an21rhpe3mkic8q9a...@4ax.com>: >> >On Sat, 31 Dec 2022 10:19:53 -0800 (PST), Ed Lee >> ><edward....@gmail.com> wrote: >> > >> >>But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken >> >>the >> >>meter. >> >> >> >>The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. >> >> >> >>Perhaps it's just same design with new label, when they got enough reports/complaints. >> >> >> >>I am wondering if it's worth picking up some of the older 1000V models off ebay. >> > >> >Buy Fluke, or at least Extech. >> On recommendation of somebody here I bought 4 multimeters on ebay >> for the amount of 4$something a piece. >> All 4 are still working... >> http://panteltje.com/pub/chinese_multimeter_img_3159.jpg >> >> Used everyday! >> >> Quite accurate. too. >> >> Guess I was lucky. > >Did you try them with 400V?Very likely, measured PMT supply stuff, but a searh for 'multimeter' in my own postings in my own newsreader found these: ##On a sunny day (Tue, 8 Nov 2011 08:07:17 -0800 (PST)) it happened George ##Herold <gherold@teachspin.com> wrote in ##<49c7230b-5eb5-4ee1-8f53-7fdaa234d079@o9g2000vbc.googlegroups.com>: ## ##>On Nov 8, 6:13�am, Jan Panteltje <pNaonStpealm...@yahoo.com> wrote: ##>> Killed one of the new 3 dollar 40 cent multimeters ##>> ##>> OK, they are only 1 kV, and I went to 1900 V and higher. ##>> So this is the third dead multimeter, ##>> it shows very erratic readings now on all ranges, ##>> chip CMOS isolation pierced I think, actually ##>> it may have seen as much as 2700 V and that while changing voltage ranges= ##>. ##>> ##>> So, anyways, I have some nice analog 100 uA (IIRC) huge meters somewhere ##>> in the attic, will add a resistor and make an analog HV meter for this PM= ##>T stuff. ##>> Or maybe some HV attenuator box for the second (and last Chinese meter). ##>> sniff sniff. ##>> At least now I have a spare 9 V battery, ##>> See good in bad :-) ##> ##>High voltage, the death of most DMM's? I killed a 'good' ~$50 DMM ##>many years ago when I hooked it up to the spark from an old 5 HP lawn ##>mower engine that wouldn't run. I was 'convinced' that the spark/ ##>switching circuitry was no good. In retrospect a little resistor ##>string could have saved me from kicking myself all day! ##> ##> ##>George H. ## ##What I think happened is that I switched ranges, while still voltage in the HV capacitors. ##In these simple PCB range switches then the CMOS input possibly gets the full ##current via the series resistor, but could be anything else of course. ## ##I looked in the attic, found 2 huge analog meters, but those turn out to be 1 mA fsd. ##That is too much load to measure stuff like this. ##So, went to ebay and ordered a 50 uA analog multimeter for 6 dollar 55 inclusive shipping: ##ebay nr 160573395515 from China. ##Cannot even buy a stand alone meter for that here. ##I also ordered 3 extra digital multimeters, the same as the other ones, 3 dollar 40 or something. ##^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ So that explains why I have still 4 working ones :-) Meters now in use since 2011, no more problems. 230 V mains AC also OK, measured that many times. :-) Life goes on
Reply by ●January 6, 20232023-01-06
Ed Lee <edward.ming.lee@gmail.com> wrote:> But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.High voltage can destroy resistors, but this seem to be quite fast.> The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it's just same design with new label, when they got enough reports/complaints.Lot of folks live in countries where line voltage is 230V. So 50 volts makes a lot of difference.> I am wondering if it's worth picking up some of the older 1000V models off ebay.I know nothing about CenTech meters. But I have several "DT830B" meters. Available schematics shows 3 resistors in series for 1000V. My oldest one have 2 resistors. Newest one have single resistor. Standard miniature resistors are rated for 250V, one can get better ones, but I doubt that one can get cheaply 1000V capable ones. Still, meter is marked as 1000V DC, 700V AC (the same as old meters). -- Waldek Hebisch
Reply by ●January 7, 20232023-01-07
On Friday, January 6, 2023 at 5:04:39 PM UTC-8, anti...@math.uni.wroc.pl wrote:> Ed Lee <edward....@gmail.com> wrote: > > But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter. > High voltage can destroy resistors, but this seem to be quite fast. > > The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it's just same design with new label, when they got enough reports/complaints. > Lot of folks live in countries where line voltage is 230V. So 50 volts > makes a lot of difference.This is for 250V DC. AC range remains at 250V as well. Peak to peak 250V AC is close to 400V DC. So, if it can handle 250V AC, it should be able to handle 400V DC.