Why My Bug Zapper Suddently Stopped Working? - Page 1
Forum section: electronics / beginners

author: Boris_yo
author_rank: Frequent Contributor
timestamp: October 08, 2011, 11:07:07 am
content: Today my fly zapper stopped working and passing voltage to the grill. The seller from UK offers 30 days free replacement including shipping however it has been more than 30 days since i bought the zapper. I don't want to tinker with it since i am affraid seller will not replace it if i do so and i don't want as well pay for shipping since the fee will be close to new zapper's price.Here i made a videoto show zapper in better detailI tested with multimeter battery compartment both cords and there wasn't circuit:What would you suggest i should do?Thanks.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: October 08, 2011, 04:28:49 pm
content: How about replacing the inner transistor with a new.

author: Zero999
author_rank: Super Contributor
timestamp: October 08, 2011, 05:14:42 pm
content: The video link doesn't work, see below for the correct link:The Executioner Is BrokenThe LED appears not to be lighting, check the switch.The circuit is very simple. It's probably just a blocking oscillator so should be easy to repair, unless it's the transformer which will be very difficult to repair as the wire used for the high voltage winding will be very fine.

author: IanB
author_rank: Super Contributor
timestamp: October 08, 2011, 09:12:04 pm
content: Bug zappers like that are usually available for peanuts from dollar stores and the like, and the build quality is likely to be correspondingly low. I'm afraid they come under the category of "cheap tat". Tinkering is likely to be your best option. Do you have any circuit testing knowledge?

author: Boris_yo
author_rank: Frequent Contributor
timestamp: October 08, 2011, 09:52:08 pm
content: This one is better than others. The makers did not want to share technical details when i asked technical question. Shipping for replacement will cost almost as new zapper.I have very little circuit testing knowledge.

author: IanB
author_rank: Super Contributor
timestamp: October 08, 2011, 10:18:54 pm
content: Without circuit testing knowledge, advanced testing is going to be difficult. The simplest thing to check is to make sure the switch is still working.Before it broke, how did the LED behave? Did the LED light up the instant you pressed the switch, or did the LED light up after some delay when the zapper was "charged up"?If the LED lit up instantly and it doesn't light up now, then probably the switch is the problem. That might be fixable.If the LED lit up after some delay and it doesn't now, then the transistor in the high voltage circuit has probably failed and that will be hard for you to fix.Sometimes these things just have to be put down to experience and you suck up the loss. When something costs more, it is no guarantee that it is better.I have never taken one apart, but I suspect the circuit inside is very similar to the flash circuit in a disposable camera. There would be a simple blocking oscillator and transformer circuit that charges up a capacitor to a few hundred volts. This voltage is placed across the strings on the device and zaps any insects (or people) that touch them. I dare say a disposable camera might have the right kind of replacement transistor needed if you were able to analyze the circuit and draw out a schematic.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: October 09, 2011, 06:06:15 am
content: This zapper has voltage multiplier or generator. After researching a bit i found voltage multipliersmentioned here.

author: westfw
author_rank: Super Contributor
timestamp: October 09, 2011, 11:01:58 am
content: A broken bug-zapper I inherited from a friend had the spring-side of the battery clip soldered directly to the PCB, and the mechanical stresses had broken that solder joint. Yours looks like it has wires, but it's worth checking. A lot of these "gadgets" have the same sort of electronic components as everything else, and failures are somewhat likely to be mechanical...

author: saturation
author_rank: Super Contributor
timestamp: October 09, 2011, 12:29:02 pm
content: These are simple electronics to troubleshoot, but you need to know what you're doing; you'll need to open it to find out. If its just a broken switch or wire then that's the easiest to fix. The most we can do online is for you to take clear detailed photos of the PCB and post it. Good luck!Quote from: Boris_yo on October 09, 2011, 06:06:15 am

author: Zero999
author_rank: Super Contributor
timestamp: October 09, 2011, 02:16:27 pm
content: It's basically a blocking oscillator.See Wikipedia.http://en.wikipedia.org/wiki/Blocking_oscillatorAnd here's a site with a practical application involving a step-up transformer and a voltage multiplier. The circuit used in the bug zapper is probably very similar to this.http://rangkaianadaptor.blogspot.com/2010/11/dc-to-dc-converters.html

author: Boris_yo
author_rank: Frequent Contributor
timestamp: October 12, 2011, 02:20:21 pm
content: I have disassembled plastic compartment and spotted loose black wire:Soldering is obvious, but i have never soldered before. I will probably need metal plate to put below soldering point so solder won't drip.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 08, 2011, 05:32:24 pm
content: Hello guys. I have got more questions like on what would i solder wire(2)with lead(1)?I have soldering scraper tool, but it is for scraping. What i can use to solder on?By the way, where is voltage multiplier?

author: Unknown
author_rank: Unknown
timestamp: November 09, 2011, 11:57:40 am
content: http://mightyohm.com/files/soldercomic/FullSolderComic_EN.pdf

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 09, 2011, 04:04:54 pm
content: Thanks Uncle Vernon! This is basic, educational and funny.By the way, anybody knows where is voltage multiplier located on the picture above?

author: Boris_yo
author_rank: Frequent Contributor
timestamp: December 20, 2011, 02:00:46 pm
content: Hello guys. I bring you update. I partly succeeded in soldering for the first time in my life. Here is why i said partly:As you can see from the video above, the zapper works but not as it supposed to. Prior i was able to feel shock and see sparks when touching zapper with hand, but now i can only feel voltage without usual static discharge. Did not try on insects by the way yet. Also when i touch with drill bit, i see some little sparks.Here is a solder i have used:Changing batteries does not make any difference.Maybe i did not let flux cleanse dirty solder enough as i did not solder on flat surface but above it more like in the air? Anybody has any ideas what could be wrong?By the way i read that solderer's tip should be cleaned with damp sponge but i have tried with scotch which i wanted to throw away anyway before. Scotch started gluing to solderer so i think it was a bad idea. Here is what i used exactly:Was i wrong to use this and will damp sponge work better?Thanks to all respondents beforehand!

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: December 20, 2011, 09:38:55 pm
content: I have two Zappers like those.The first that I got originally, in a week it drop from the 5000V to 250V.I did open it up, and all components look good, but no 5000V, I contact the ebay seller and he did send me a replacement that works for over a year.The tricky part could be the single transistor in it, but I did not search yet for a replacement.The part code looks unknown by speaking about branded makers.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: December 20, 2011, 09:43:17 pm
content: For me it would cost as a new zapper to send this one for a replacement.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: December 20, 2011, 09:58:56 pm
content: In my case I did not had to send back the damaged, this is why now I have 2 of them.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: December 20, 2011, 10:36:53 pm
content: How is your zapper called?

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: December 20, 2011, 11:01:47 pm
content: https://www.eevblog.com/forum/index.php?topic=453.0https://www.eevblog.com/forum/index.php?topic=453.msg9121#msg9121

author: Zero999
author_rank: Super Contributor
timestamp: December 22, 2011, 08:37:11 pm
content: Quote from: Boris_yo on November 08, 2011, 05:32:24 pmThe voltage multiplier is on the right hand side of the picture. It'll consist of the small blue capacitors and diodes hidden under the brownish-red rectangular capacitor.Have you tried activating the high voltage circuit without the grid connected? If so it's possible one of the capacitors or diodes has been subjected to over voltage conditions and has failed. In other words the grid protects the components from high voltages by arcing over when the voltage exceeds a certain level and operating the high voltage without it may damage it.