Discharging leads is always a good practice. It is standard procedure to discharge all leads connected to anything on a spacecraft to prevent electrical over stress. Sometimes the capacitance of the leads can store enough charge to damage very sensitive circuits.
I've spent hundreds of hours reverse engineering PCBs and my best decision was giving up the paper and pen for a schematic editor. I use KiCAD personally and the ability to just freely rearrange components and traces around instead of making a ratsnest on paper has saved a lot of time and confusion. Highly recommended.
I got the gist of it. Lost you on the detailed circuit traces. I'll dig up a dead meter and try to trace similar paths to look for analogous elements. Yeah, I'm waiting for that 61e+ report. Did it make it past the piezo? Replacing a ptc with resistor was a worthy idea. Why didn't Uni-t think of that?
Curious if the 287 has the same problem ? If not, perhaps we have a little more evidence for why Fluke discontinued the 189 ? Well, I guess this is just one more cognitive load issue to add if I'm ever checking high AC voltage with my 189. I'll often use the AC modes to check for voltages when troubleshooting unknown circuits, so this is critical info to know (and maybe explains past odd behavior). Thanks for the great detail on the issue and alerting us 189 owners of the problem !
I doubt this is unique to the 189. It just happened to be the meter we were discussing. I think the example someone provided, they had caused a failure at much lower voltages than shown. Not too surprising.
@@joesmith-je3tq yeah, that's the scenario I envisioned too. I recall a time I was troublehsooting an EVSE and checked the input and output of a 240vac => 3.3v solid state IC and can easily see how if not shorting the leads between measurements, could have inadvertently caused residual damage. Thanks again.
Discharging leads is always a good practice. It is standard procedure to discharge all leads connected to anything on a spacecraft to prevent electrical over stress. Sometimes the capacitance of the leads can store enough charge to damage very sensitive circuits.
I've spent hundreds of hours reverse engineering PCBs and my best decision was giving up the paper and pen for a schematic editor. I use KiCAD personally and the ability to just freely rearrange components and traces around instead of making a ratsnest on paper has saved a lot of time and confusion. Highly recommended.
That sounds like a very interesting undertaking! Are you willing to share your results!
Good advice Joe, better safe than sorry... looking forward to the uni-t video
I got the gist of it. Lost you on the detailed circuit traces. I'll dig up a dead meter and try to trace similar paths to look for analogous elements.
Yeah, I'm waiting for that 61e+ report. Did it make it past the piezo? Replacing a ptc with resistor was a worthy idea. Why didn't Uni-t think of that?
Curious if the 287 has the same problem ? If not, perhaps we have a little more evidence for why Fluke discontinued the 189 ? Well, I guess this is just one more cognitive load issue to add if I'm ever checking high AC voltage with my 189. I'll often use the AC modes to check for voltages when troubleshooting unknown circuits, so this is critical info to know (and maybe explains past odd behavior). Thanks for the great detail on the issue and alerting us 189 owners of the problem !
I doubt this is unique to the 189. It just happened to be the meter we were discussing. I think the example someone provided, they had caused a failure at much lower voltages than shown. Not too surprising.
@@joesmith-je3tq yeah, that's the scenario I envisioned too. I recall a time I was troublehsooting an EVSE and checked the input and output of a 240vac => 3.3v solid state IC and can easily see how if not shorting the leads between measurements, could have inadvertently caused residual damage. Thanks again.
Actually the capacitance of oscilloscope leads can also store quite a charge and be dangerous.
So valuable to me👍
Very interesting. Thanks.
I learned a lot today.
Another trap for home gamers.