• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Repair Levoit air purifier PCB due to wrong 240V AC power plugged in.

hanschee

New Member
Greetings! Found this forum searching for help to repair a Levoit air purifier and hope to get some tips.

Long story short - the 110/120v rated PCB is "blown" due to plugging into wrong 220/240v power supply. A visual inspection showed a blown Varistor, which I bought a replacement from eBay and replaced/resolded it as per the photos below. Tested it with 120v power after this but still not working - no led lights nor any indication that power is flowing. I know how to do some soldering but in no way know how to "test" or troubleshoot a circuit board. This one seems no too complicated and I hope someone here can show me some way what else to check or which component to check (and how to check it) with a multi-meter, e.g. which component to test and what to expect. Thanks in advanced!

Photo 21-10-19, 10 38 41 PM.jpg
Photo 21-10-19, 10 39 00 PM.jpg

The two "ugly" component legs which I soldered on the top left corner is the new varistor (VR1) replacement. I bend it towards to next component in line as the original trace linking them seems to be broken. At this point, I have no clue what else to check or replace, although the blacken patch may give a hint. Still, I'm not educated enough to do further troubleshooting. Please help! Hans
 

sagor1

Active Member
That little 4 legged device on the bottom appears to be a bridge rectifier. Odds are high it was blown as well.
The brown rectangular thing on the top of the board seems to be a 2.5A fuse of some sort, check that to see if it is open.
 

hanschee

New Member
The brown rectangular thing on the top of the board seems to be a 2.5A fuse of some sort, check that to see if it is open.
Yeah! That's open!
I didn't know it's a fuse until I do a search on "392 2.5A 250V" giving results on "Square Fuse".
I removed it just now and solder a wire across (temporary) and the air purifier works now!!!
I didn't know fuses come in "square"... LoL
Thank you very much sagor1
 

EE World Online Articles

Loading

 
Top