Excellent work Joe. I for one really appreciate this kind of mod. I worked for 10 years in a calibration lab and I can really get the attraction if improving instrument performance, and especially a cheap/popular meter like the 61e. Well done.
Thanks and I'm glad you enjoyed it. I used that 61E for so many demonstrations where I made changes to it that I ended up giving it its own playlist. You can find that off the main page.
Incredible improvement! Great video! I've ordered the UT61B to be my next hobby level multimeter for daily driving. I'm keen on doing some simple mods like you have.
Very nice! I'm very happy with your videos as I have ut61e too :). I know some people hate it, but I find it adequate for money and for 240V :). I consider buying 869s as well because of its dual display.
I would guess most of the drift is from the divider network, rather than the reference, or they are both drifting in the same direction. Would also probably help to measure the pot value, and trim further so you only need a 100R pot or even a 50R instead, or just use exact value resistors instead. That though is not a good production line method though, unless you use a series of resistors and break them open to trim up instead.
The diode will change with temp. Running one sweep, I knew where we would need to place the compensation. Difficult part is trying to match it. As you can see, it can be done with fairly good results and very little cost. If comment below is correct and there are problems with long term stability, I would have a look at the cheap potentiometers on the board. Knowing what mode it drifts would help to know which parts to look at. Hope this helps.
Очень познавательное видео,спасибо.Если я верно понимаю,штатый делитель напряжения остался неизменным,за исключением подстроечного резистора VR1,который вы заменили на 1к.А так же вы допаяли дополнительную последовательную цепочку 6.65к 1% и диод BAV199 параллельно керамическому конденсатору С17,кстати какой у него номинал ёмкости и вид диэлектрика?
Being it was seven years ago, I would be guessing. Judging by the package size, appears to be X7R. I would expect COH/NPO to be much larger. From the video, keep in mind there is no once size fits all. You will need a thermal chamber to compensate one. Still, those values may make a good starting point. Good luck.
@@joesmith-je3tq Но вы же меняли детали,в том числе переменный резистор,неужели после замены вы не настраивали переменый резистор по эталонному напряжению?
Hi, well, I saw a few posts on various forums talking about drift over time being a big issue on the 61E, I got mine early this year so not really too much time to notice something, I checked the voltage readings with a AD584K voltage reference on April and was just about 1mv off from the "certified" card on the VR, and I just checked now and it's the same values for the 4 voltages of the VR. [vref] (what is supposed to be) 02.5 2.49895 05.0 4.99767 07.5 7.49586 10.0 9.99345 UT61E (02.04.16) 02.5 2.497 05.0 4.996 07.5 7.494 10.0 9.992
Hi, i think all cheap meters with analog adjustment will be improve by better and low value potentiometer. Because falls, temperature, humidity affect to low quality potentiometer dramatically.
I have checked 3 same class meters for temperature, long term stability- Victor 86E(external reference), UT61E, VC9807(digital adjustment). No surprise digital adjustment win.
Yea, I have not seen a lot of long term drift data for the 61E beside a few people mentioning it. I did look at the smaller trimmers used on the meter TechnologyCatalyst supplied along with mine. Keeping in mind that I have changed VR1, I have gone ahead and recorded DCV, resistance and capacitance after I had aligned just VR1. I'll check it from time to time. Really haven't seen much of a problem with drift with the cheep meters I actually use. These get heat cycled and such sitting outside.
I can assure you after almost 45 years of experience in repair that I have never been able to work at temperatures higher than 45C. The drift of my multimeter -in that case- was secondary importance
Joe, Is it really necessary to care about the drift. I never use the meters in such a extreme temperature environment.For me it's quite understandable that the meters will drift in those temps.
I can't answer if you need to care about temperature drift. If the question is if "I" care if the UT61E drifts, I cared enough to show people how to address it for less than a cup of coffee. I have no plans to ever use this UT61E beyond using it as an aid in these demonstrations, even though it is turning into a better meter each time I get into it.
Joe, if it was just about the UT61E, then it's okey. I thought you use the 61e as an example to show temp drift. Thanks anyway for the upload. I always enjoy your videos. If i ask you a question, it's not to fight you, but rather to get a better understanding.
From the video, I originally ran all the meters I had and posted the results. Someone then asked about running the 61E specifically. There were enough posts about adding the reference along with the drift of this particular meter, now that I have another one available it seemed worth while to repeat the test and try to improve the design.-20 to 60 may seem a little excessive for this particular meter but my goal was to determine the drift. Pushing the meter to a wider range provides me with more data. The fact it had no troubles running across such a wide range compared with the TPI that could not power up at -10, just shows it's not all that bad when it comes to temperature. As far as if you personally need to care about temperature drift in general, I have no idea.
If you had actually watched the video, you would know that this PCB is the newer design and that I compensated the original reference, not replaced it.
Excellent work Joe. I for one really appreciate this kind of mod. I worked for 10 years in a calibration lab and I can really get the attraction if improving instrument performance, and especially a cheap/popular meter like the 61e. Well done.
Thanks and I'm glad you enjoyed it. I used that 61E for so many demonstrations where I made changes to it that I ended up giving it its own playlist. You can find that off the main page.
Incredible improvement! Great video! I've ordered the UT61B to be my next hobby level multimeter for daily driving. I'm keen on doing some simple mods like you have.
Very nice! I'm very happy with your videos as I have ut61e too :). I know some people hate it, but I find it adequate for money and for 240V :). I consider buying 869s as well because of its dual display.
Thanks, I'm glad you are enjoying them.
I would guess most of the drift is from the divider network, rather than the reference, or they are both drifting in the same direction. Would also probably help to measure the pot value, and trim further so you only need a 100R pot or even a 50R instead, or just use exact value resistors instead. That though is not a good production line method though, unless you use a series of resistors and break them open to trim up instead.
Hi Joe, very interesting mod.
How the diode and resistor acts in the node compensating the change in the temperature?
The diode will change with temp. Running one sweep, I knew where we would need to place the compensation. Difficult part is trying to match it. As you can see, it can be done with fairly good results and very little cost. If comment below is correct and there are problems with long term stability, I would have a look at the cheap potentiometers on the board. Knowing what mode it drifts would help to know which parts to look at. Hope this helps.
Очень познавательное видео,спасибо.Если я верно понимаю,штатый делитель напряжения остался неизменным,за исключением подстроечного резистора VR1,который вы заменили на 1к.А так же вы допаяли дополнительную последовательную цепочку 6.65к 1% и диод BAV199 параллельно керамическому конденсатору С17,кстати какой у него номинал ёмкости и вид диэлектрика?
Being it was seven years ago, I would be guessing. Judging by the package size, appears to be X7R. I would expect COH/NPO to be much larger. From the video, keep in mind there is no once size fits all. You will need a thermal chamber to compensate one. Still, those values may make a good starting point. Good luck.
@@joesmith-je3tq благодарю,жду когда приедут детали.
Джо,на каком референсном напряжении вы настраивали мультиметр после замены деталей и добавления цепи термокомпенсации?
I assume what ever it was originally, or it would have thrown the OEM's alignment.
@@joesmith-je3tq Но вы же меняли детали,в том числе переменный резистор,неужели после замены вы не настраивали переменый резистор по эталонному напряжению?
@@РоманОпалев-з8ь Yes and I would have set it back to the same value I read before the modifications.
Awesome, will this mod also improve the drift over time of the 61e?. Thanks.
I really have no idea what the longer term drift of the UT61E is. Are you seeing a particular mode changing a lot? If so, post your findings.
Hi, well, I saw a few posts on various forums talking about drift over time being a big issue on the 61E, I got mine early this year so not really too much time to notice something, I checked the voltage readings with a AD584K voltage reference on April and was just about 1mv off from the "certified" card on the VR, and I just checked now and it's the same values for the 4 voltages of the VR.
[vref] (what is supposed to be)
02.5 2.49895
05.0 4.99767
07.5 7.49586
10.0 9.99345
UT61E (02.04.16)
02.5 2.497
05.0 4.996
07.5 7.494
10.0 9.992
Hi, i think all cheap meters with analog adjustment will be improve by better and low value potentiometer. Because falls, temperature, humidity affect to low quality potentiometer dramatically.
I have checked 3 same class meters for temperature, long term stability- Victor 86E(external reference), UT61E, VC9807(digital adjustment). No surprise digital adjustment win.
Yea, I have not seen a lot of long term drift data for the 61E beside a few people mentioning it. I did look at the smaller trimmers used on the meter TechnologyCatalyst supplied along with mine. Keeping in mind that I have changed VR1, I have gone ahead and recorded DCV, resistance and capacitance after I had aligned just VR1. I'll check it from time to time. Really haven't seen much of a problem with drift with the cheep meters I actually use. These get heat cycled and such sitting outside.
I can assure you after almost 45 years of experience in repair that I have never been able to work at temperatures higher than 45C. The drift of my multimeter -in that case- was secondary importance
As I've mentioned, opening the test limits was done to increase the spread.
Joe,
Is it really necessary to care about the drift. I never use the meters in such a extreme temperature environment.For me it's quite understandable that the meters will drift in those temps.
I can't answer if you need to care about temperature drift. If the question is if "I" care if the UT61E drifts, I cared enough to show people how to address it for less than a cup of coffee. I have no plans to ever use this UT61E beyond using it as an aid in these demonstrations, even though it is turning into a better meter each time I get into it.
Joe, if it was just about the UT61E, then it's okey. I thought you use the 61e as an example to show temp drift. Thanks anyway for the upload. I always enjoy your videos.
If i ask you a question, it's not to fight you, but rather to get a better understanding.
From the video, I originally ran all the meters I had and posted the results. Someone then asked about running the 61E specifically. There were enough posts about adding the reference along with the drift of this particular meter, now that I have another one available it seemed worth while to repeat the test and try to improve the design.-20 to 60 may seem a little excessive for this particular meter but my goal was to determine the drift. Pushing the meter to a wider range provides me with more data. The fact it had no troubles running across such a wide range compared with the TPI that could not power up at -10, just shows it's not all that bad when it comes to temperature. As far as if you personally need to care about temperature drift in general, I have no idea.
Ehmm they changed PCB now.. this fix can't be done anymore.. on new pcb there is not external place for LT1790. (bought from Amazon some month ago)
If you had actually watched the video, you would know that this PCB is the newer design and that I compensated the original reference, not replaced it.
What? You not going to include the fluke 97 with that really special temperature probe? 😁
Too bad that the Fluke can't measure down this low.
There will be never an review on the Vc-890 multimeter ???
TechnologyCatalyst did one that may be found here:th-cam.com/video/DT2MU32la2c/w-d-xo.html
joe smith I wonder what happened with him. I did send him an email a couple weeks ago and no reply. Not like him to not reply. Hoping he is OK.
Perhaps on vacation and eating too much turkey? I did post the battery test results. Looks good.