Mikes electric stuff did an autopsy of a panasonic microwave that was destroyed by a PCB fuse, so it's not just crappy no brand consumer stuff that uses them. Additional thought 1 - I'm guessing you used 110V mains to destroy the PCB fuse, but the unit is rated for 240V input and if so I'm sure that you'd have got much more spectacular fireball at it's top rated input.
thought 2 - just relating to incandescent bulbs. In the UK we have 230V mains and fused plugs. the lowest rated fuse common in those plugs is 3A which would seem appropriate for a 40 or 60W lamp but it was pretty common to need to replace that 3A fuse after the bulb filament blew implying a momentary fault power of I guess >1000W... never saw it happen with a 5A or 7A fuse though. FWIW These are sand filled ceramic tube fuses, not quick-blow.
I purchased a Panasonic Microwave. After a few uses, the internal 20 amp fuse blew. It worked with a new fuse but I decided to return it because of the electrical design. Our wall outlets in Canada are 120 volt 15 amp circuits. Microwave ovens are considered an appliance that needs a separate outlet direct to a 15 amp braker in the electrical panel. I personally thought the unit may have other issues and did not want to find out after the warranty period expired. A PCB fuse is lame and cheap, meant for disposable products. Are Pico fuses too expensive?
Thanks for this. I've just cracked open a similar unit configured as a 12V power supply. The chip is marked CSC7136D as far as I can see. "F1" is a ratty-looking 1Ω resistor, not a fuse - and this is for 240V operation in the UK. I reckon weight correlates with product safety for these little PSUs.
Great content as always. One big takeaway is that you can't trust the current ratings on some of these USB power adapters. Running them at full spec. can result in voltage droop and worse yet, overheating. It's probably best to de-rate them for your application just to be on the safe side.
More attention should be paid to these deadly little chargers. Here in Thailand, it's common to read of people being electrocuted by their charging cell phones.
@@KerryWongBlog - using Metric means that you can directly apply conversions to °K and compare delta temperature rises. Also, 90% of your world audience won't understand US measurements.
Kerry, I believe you caused a short circuit by soldering the black wire directly across the PCB fuse. Instead, the black wire should be connected to the corner pad, allowing the bridge rectifier to do its job. Was this intentional?
Mikes electric stuff did an autopsy of a panasonic microwave that was destroyed by a PCB fuse, so it's not just crappy no brand consumer stuff that uses them.
Additional thought 1 - I'm guessing you used 110V mains to destroy the PCB fuse, but the unit is rated for 240V input and if so I'm sure that you'd have got much more spectacular fireball at it's top rated input.
thought 2 - just relating to incandescent bulbs. In the UK we have 230V mains and fused plugs. the lowest rated fuse common in those plugs is 3A which would seem appropriate for a 40 or 60W lamp but it was pretty common to need to replace that 3A fuse after the bulb filament blew implying a momentary fault power of I guess >1000W... never saw it happen with a 5A or 7A fuse though. FWIW These are sand filled ceramic tube fuses, not quick-blow.
I purchased a Panasonic Microwave. After a few uses, the internal 20 amp fuse blew. It worked with a new fuse but I decided to return it because of the electrical design. Our wall outlets in Canada are 120 volt 15 amp circuits. Microwave ovens are considered an appliance that needs a separate outlet direct to a 15 amp braker in the electrical panel. I personally thought the unit may have other issues and did not want to find out after the warranty period expired. A PCB fuse is lame and cheap, meant for disposable products. Are Pico fuses too expensive?
My induction hob has a PCB fuse on the entry card !!!
230 V - max power 7,2 KW
Thanks for this. I've just cracked open a similar unit configured as a 12V power supply. The chip is marked CSC7136D as far as I can see. "F1" is a ratty-looking 1Ω resistor, not a fuse - and this is for 240V operation in the UK. I reckon weight correlates with product safety for these little PSUs.
Great content as always. One big takeaway is that you can't trust the current ratings on some of these USB power adapters. Running them at full spec. can result in voltage droop and worse yet, overheating. It's probably best to de-rate them for your application just to be on the safe side.
That is a super-dodgy power adaptor indeed
It was designed as a space heater that can be used as a charger.
More attention should be paid to these deadly little chargers. Here in Thailand, it's common to read of people being electrocuted by their charging cell phones.
For the benefit of non-US viewers, 180 F is about 82 C.
What was the temperature in C, not stupid F. 182.8F means nothing to me.
I probably should stick to metric system. Anyway it's 83.8 degree Celsius.
@@KerryWongBlog - using Metric means that you can directly apply conversions to °K and compare delta temperature rises. Also, 90% of your world audience won't understand US measurements.
You could've googled it instead of making a comment lol
Bam! You got it!
Teşekkürler.. güzel bir sunum..
Kerry, I believe you caused a short circuit by soldering the black wire directly across the PCB fuse. Instead, the black wire should be connected to the corner pad, allowing the bridge rectifier to do its job. Was this intentional?
I thought I mentioned in the video that was the intention.
I would like to have seen how hot it got with a more typical load. Or rather, determine what it's maximum load is without it getting dangerously hot.
Some time, check out Dave Jones review of an older Extech convertible tweezer/probe DMM. He had an NDE.
I wouldn't charge my stuff overnight while I'm sleeping with one of these .
I just trust Apple when it comes to these chargers