I resolved the 130v+ issue. It turn out to be a capacitor in series with the main prong and the 100 ohm resistor. Capacitor value 0.47uF. Hope this help.
I'd expect that larger diode with its cathode connected to the R/C dropper to be a zener, setting the input voltage to the 7805 and transistor/zener regulator. The extra 6V rail is probably there to give more output swing from the opamp which can't reach all the way to its positive supply on the output.
the metal buttons is because of the analog reading. With carbon resistance is inconsistent. ......"the load crystals for the capacitor".... I wander, when you paid for it you would guessed what's inside from the price. Why did you bought it then? You understand well what's probably under the cover. And yet you didn't search for better one for 10 times the price of this one. I'm not accusing you, it's a honest question. I'm trying to understand how the electronics market works
I actually have a different rev of that board, which has a QFP for the processor, but it's either soldered on 'dead-bug' style, or they ordered them with no markings as it doesn't look like they've been etched off. Also, the op-amp on mine is a DIP package, and only one transistor which is a SOT package. May try to post pics later... Incidentally, my KAW has developed the same 'high' voltage reading, and a flickering display... I may try reading the contents of the eeprom too...
I have an Irish version one of these and its also gone out of cal. It reads 213v and the accual voltage is 232. The current is wayyy off. It reads several thousand amps running a pc. I havent found why its doing this though.
I watched another video that was made in 2015 and there is a fuse right next to that brass bar thing by the plug now. IDK if they upgraded the design a bit?
It's not that they're cheap that I find remarkable, it's that this is sold retail in america. I bought these at a local Frys, for FSM's sake! If they were e-bay specials out of china, it would be expected. However, they have *supposedly* passed all US safety regulations.
That, and you have 240V there. This is designed for 120V from the ground up. I don't think there is any way to convert these to 240 without completely redesigning both PCBs,
Leakage to ground can be measured while certifying. Leakage between hot and neutral - well it's supposed to have leakage because it consumes power. even though it sounds funny to say that it's certified. Maybe they just want to pass a simple test that they'll do on product import in order to allow it as "safe". Certification doesn't seam an option for this unit :)
I have the same kill-a-watt meter you do, and it looks a bit different on the inside. My meter has a date code on both boards of 4813, where yours has 4909 and 4309. The insides are very similar but some things have been changed. The other thing is my unit looks to be wave soldered and not hand soldered. I can take some pictures of the boards if you would like to compare the two.
4.194304 MHz = 1/(2^22), so 22 flip flops or a 22 bit counter give/gives you a pulse every second. That was the most used frequency before they used PLL and 32768 Hz crystals. Agreed on the very bad soldering job there, i think i have never seen worse.
My friend has one of these that actually got hot enough (I assume it was the shunt that got hot) and melted/deformed the case.Surprisingly it still works fine. I have heard a lot of similar stories to your "dead after 3 months" saga. Also,they don't seem to stay in cal long,if they were even cal'd from the factory.(Some of them are wayy out,right out of the box.)
@13:00 Sure enough, it is an eeprom, however there's nothing intelligible in it, just calibration data from what I gather by reading the one in my KAW (read as a 24Cxx series eeprom, only 56 bytes used).
Its nice of them to try and burn their customers' houses down. I wonder what an accurate estimate of how many houses burnt because of these would look like.
I was very surprised when I dismantled a 'UK' equivalent. Similar price bracket, but CT rather than current shunt, proper Cirrus power measurement IC, some sort of masked 8051 core thing. Very nice looking board and layout.
+Yosef MacGruber It was a joke. You asked for a solution to dental issues - soylent is a liquid "food" that you could probabably feed people through a feeding-tube, which would hopefully prevent food build up/plaque, since people wouldn't have food in their mouths anymore.
They're probably much more concerned about creepage before the fuse, since that could result in a pretty violent current flowing. After the fuse the short circuit current is limited (somewhat, those glass fuses can interrupt at least 30A IIRC). Still almost aggressively irresponsible to put the mains potential on the conductors right next to each other on that presumably not mains-rated ribbon cable. If they put the PE between the two that would half the voltage and increase safety a bit.
