Quote:
Originally Posted by Vicegrip
I kid! So which voltage is it? 9.44 or 9.43?
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Hard to know. The two expensive, made-in-USA recently calibrated Flukes say 9.43, but the sub $100 made in China meter says 9.44. Who knows?
Funny thing about this pic is that shot is after I did a quick home brew calibration on the red meter. The first test I did on the E46 was to put the 87V on the battery (12.4V) and use the red meter in the engine compartment, where the voltage on the main terminal under the hood was 12.1V. Holy crap - what is dropping 0.3V on a 000 cable? Answer: nothing. The red meter is just 0.3V out of cal on DCV.
Since this is an old chinese made meter it's not really worth sending out and spending $100 to get my $100 meter calibrated. I contacted ESI (the brand on the meter) and asked for cal instructions, to which they said "lol no". This is actually a rebranded CEM meter, and they sell it through many other makers like Extech, so I contacted them as well. Again, "lol no". So I said fuck it, I'll do it myself. Worst case I ruin the meter, but a meter that is almost 3% out of cal on DCV is useless anyway so nothing to lose.
Opened it up and there was 8 different adjustment pots on the PCB. I used a method I found on EEVBlog where your set the meter to the measurement you want and freeze the suspected adjustment pot with electronics freeze spray. The pot that freezes and affects the display is the one and holy shit it worked.
Here's a shot right after the homebrew calibration showing it next to my 87V and a 117 I got a couple months ago.
