What about some lighter solvents like IPA? I don't often use racing fuel on my bench but the IPA comes out quite often.
Then there's the acetone ... I try not to use that one the bench though.
I expect acetone would make a mess of just about any meter but these are supposed to be tough and "industrial". Maybe try it on some of the less important lettering.
Non-destructive testing of the Keysight U1282A.
AFAIK the vertical reading tends to be preferred by this audience as well (in contrast to sideways).
I have an Ideal branded clamp meter (Pretty sure it's actually a Uni-T ). And they have this really neat dual display. I was expecting it to be gimmicky, but I have used the display on the end of the meter often.That is pretty neat indeed and I can see its practical aspects.
Although I wonder if it weakens the housing.
I tried to find the OEM but to no avail. I tried CEM, Mastech, Uni-T and Appa.
It looks like they did the housing pretty well. There is additional plastic ribbing to reinforce the display and input jacks.
I can't say for sure who the OEM is, but the interior build looks suspiciously similar to my Uni-T 210e. It appears to be (the scratched off the label) the same DM1106 controller chip. If they weren't made by the same OEM, they appear to have been based off the same reference design.
Great testing, Joe! I only wish you had put in the chamber the meter with the same Hycon chipset to see if we could further isolate the root cause of the issue down to the processor/chipset itself (my best bet, since the meter became "frozen") or another component (XTAL, voltage regulator, etc.). From where we see, there is a chance that Brymen's chipset might be better fabricated than Hycon, but we can only speculate.
AFAIK the vertical reading tends to be preferred by this audience as well (in contrast to sideways).
I have an Ideal branded clamp meter (Pretty sure it's actually a Uni-T ). And they have this really neat dual display. I was expecting it to be gimmicky, but I have used the display on the end of the meter often.That is pretty neat indeed and I can see its practical aspects.
Although I wonder if it weakens the housing.
I tried to find the OEM but to no avail. I tried CEM, Mastech, Uni-T and Appa.
It looks like they did the housing pretty well. There is additional plastic ribbing to reinforce the display and input jacks.
I can't say for sure who the OEM is, but the interior build looks suspiciously similar to my Uni-T 210e. It appears to be (the scratched off the label) the same DM1106 controller chip. If they weren't made by the same OEM, they appear to have been based off the same reference design.Thanks for sharing the pictures; indeed the bottom display seems sturdy.
Looking at the PCB silk screen, it seems to me an original design from Ideal: the model number 61-757 is shown in both PCBs.
Non-destructive testing of the Keysight U1282A.Great testing, Joe! I only wish you had put in the chamber the meter with the same Hycon chipset to see if we could further isolate the root cause of the issue down to the processor/chipset itself (my best bet, since the meter became "frozen") or another component (XTAL, voltage regulator, etc.). From where we see, there is a chance that Brymen's chipset might be better fabricated than Hycon, but we can only speculate.
Another aspect: when you rotated the switch after the low temp tests, was the meter already back at a specified temperature of at least -20ºC?
The reason is that the material might have become brittle at such low temperature and rotating it might degrade it (microfissures?) which would add another variable to the rotary switch tests.
Great testing, Joe! I only wish you had put in the chamber the meter with the same Hycon chipset to see if we could further isolate the root cause of the issue down to the processor/chipset itself (my best bet, since the meter became "frozen") or another component (XTAL, voltage regulator, etc.). From where we see, there is a chance that Brymen's chipset might be better fabricated than Hycon, but we can only speculate.
May I suggest comparing the Hycon chip datasheet/pinout with the "custom" chipset in the BM789.
Great testing, Joe! I only wish you had put in the chamber the meter with the same Hycon chipset to see if we could further isolate the root cause of the issue down to the processor/chipset itself (my best bet, since the meter became "frozen") or another component (XTAL, voltage regulator, etc.). From where we see, there is a chance that Brymen's chipset might be better fabricated than Hycon, but we can only speculate.
May I suggest comparing the Hycon chip datasheet/pinout with the "custom" chipset in the BM789.
I'll leave the reverse engineering to others. It's certainly something you could do. Anytime I have dove into a design, it was to get some idea why a meter failed my tests or how to improve it.
Pretty cool tests, seems to be a very robust DMM.
Thanks for explaining about the testing box.
I don't think the testing box is "useless", yes you are using it just to know if the meter still working; but I'm sure that could be much better if you at least provide a table with the "correct" value of each reference, maybe the meter could be a little off after the tests.
I know, nothing there is accurate and can vary a little when the temperature or power supply changes, but at least is better than not knowing the correct value.
Again, I assume the meters are within their manufactures specs when I buy them. Had my goal been to verify their calibration, I would rent a calibrator. That said, this does seem to be Defpom's area of interest. Mine is how robust these meters are.
I would have liked to ran the Keysight open fused at 2kV like the standard calls for and just see what happens. It's not been a problem but this is the first time I have seen a meter load my supply like this.
Wait... It looks like your Applied KilloVolts power supply is capable of 40ma. That would imply that the 1282A is dissipating about 80W somewhere.
For comparison the BM78x uses a of 5MOhm resistor per amp jack for the lead sense which if my math is correct it would be expected that the current draw with 2KV applied would be around 0.4ma and Brymen used 2W resistors to handle the power (expected 0.8W) dissipated. That's a significant difference between the different meters.
Did you run this test on the BM78x meters? I don't remember seeing it in any of the videos.
Wait... It looks like your Applied KilloVolts power supply is capable of 40ma. That would imply that the 1282A is dissipating about 80W somewhere.
To save you time searching.
Chemical: 21:44
Open Fuse: 22:55
Finally, the meter is damaged at 12kV (more than double what my first Keysight was damaged at): 57:47
After 50,000 full rotations on the switch: 1:15:00
Attached showing the last time I checked my UT61E, representing almost 6 years of data. Of course, this meter is highly modified for educational purposes only.
It's.too bad the Uni-T aren't very robust. They seem like great measuring meters and certainly fall under the bang for buck category. If they made them just a bit more robustly they could be great meters! I really wonder how muchlre it would cost them to make them just a bit better. It seems they are willing to spend money on parts in their better meters.
Thanks for the link. I probably don't remember that test because it.was too uneventful.
I honestly think that poor meter got the most scrutiny of any of your videos I watched. It certainly says something when a meter takes that much poking and proding and comes out that good. It certainly seems the Flukes and Brymens are in a special league with little company!
It's.too bad the Uni-T aren't very robust. They seem like great measuring meters
This is the difference Brymen brings. Brymen has proven they are interested in producing a good product.
Wait... It looks like your Applied KilloVolts power supply is capable of 40ma. That would imply that the 1282A is dissipating about 80W somewhere.
Yep. This needs investigating... where is all that power going?
Does it do it with the switch in the "off" position?
Edit: I guess it survived though, and an 8kV transient is only going to push something like 200mA through it for an instant, it will probably survive that, too.
OTOH it doesn't inspire confidence. It doesn't say "we made it as good as possible!", it asks "where else did they cut corners?"
I did not try this test in the off position, only in the Amps range that was being tested at that time.
Looks like I could borrow a supply what would get us to 150mA. The standard calls for 500VA but it may be enough to damage the meter. I think the first step is to trace this section out and see what these top Keysight engineers have done to cause such a high load.