hello, Tl:dr At Bottom
I am a novice when it comes to repair, and the item I am repairing is cheap but I figured I’d take a go at it. I also hope I chose the right thread to start this conversation in, and if i didn’t, please point me to the right place to ask these questions.
a friend of mine gave me a coke mini fridge they bought from Walmart that malfunctioned to see if it could be saved. i figured it could be a good learning project to try and repair it.
the fridge uses a Peltier device. the main board for the fridge is for an AC 120v connection which is what im working on. there’s also a separate plug that just wires directly to the on/off slide switch for DC 12v.the first time around trying to fix this power supply, I identified Two Faulty Capacitors (Originals where 25v 1000uf Low ESR) where one was puffy at the top and the other leaked.
i replace those with these panasonic capacitors i bought on DigiKey with identical ratings except that they had no indication that they were Low ESR and i miscalculated the size and they were a bit taller. but they fit inside perfectly anyway and they fixed the issue with the device powering on so i let it slide.
a few months later, the slide switch overheated and i think it melted. device no longer powers on and the slide switch no longer moves back and forth, it is stuck in its position no matter how hard I try to move it. id like to think the device is old and the switch reached its EoL because of its cheap parts, but the back of my head thinks its the capacitors I installed that is to blame since they are not Low ESR Rated(?). im not sure, but i do know that i need a new slide switch and i cant identify it for the life of me.
TL;DR
how do i identify this slide switch and what would be a suitable replacement for it?
also, may be a bit too much to ask, but was my capacitor choice incorrect for this application?
I’d like to learn more and order necessary parts while I’m at it but not sure where to start
Welcome to the forum.
Melting of a switch is always caused by too much current flowing through it. The discoloration visible on the bottom of the PCB at the switch does imply to me that it burned from overcurrent.
However it may also be that it just broke mechanically. (the most common failure of inexpensive slide switches)
If you desolder the switch from the PCB you’ll see that the whole switch comes apart just by bending up the four metal tabs that hold the phenolic terminal plate on the frame. When you loosen the tabs and open the switch, if the metal terminal contacts and/or wiper inside are melted, then the failure was over current.
The only way the wrong ESR value for the capacitors would cause an overcurrent failure is if the higher ESR made the power supply put out too high a voltage. That would make all the powered components draw too much power drawing too much current for the switch to handle.
Because the switch is two rows of three terminals it is most likely a DPDT switch. Photos of the inside of the phenolic terminal plate and wiper attached to the handle should allow me, or someone else around here, to confirm the pole/throw arrangement and failure cause.
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Hi DuctTape88,
Welcome to the DigiKey tech forum community.
I found a somewhat low esr electrolytic cap with those ratings of 1000uF and 25V in p/n 399-6659-1-ND. This one does have a little bit bigger diameter of 13mm instead of 10mm of the one you chose but it is not quite as tall and has the same lead spacing. The ESR on it is 46mOhm. I think your choice of capacitor was just fine but when I looked at the data sheet of it the ESR was not listed there either so if you were after a lower ESR type maybe going with ones that had ESR actually marked would be a bit more informative at least.
In order to ID the switch we will need a bit more info. Mainly the function of the switch as we can see the voltage marked on it already. The terminals on the bottom as Paul said give a clue as to the circuitry of it, likely a DPDT. and we know that the termination is through hole. Unfortunately the only DPDT 250VAC through hole switch we have in stock currently is On-On type X22205A-437W-ND.
If you confirm the switch function we may be able to locate something more suitable.
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hello again,
I’m sorry for the late reply, but i finally got around to taking apart then slide switch like instructed.
i had to enlist help to get it off of the PCB as not only am i inexperienced, but my tools would not get the job properly. the switch has 2 rows of three tabs on the bottom but taking it off of the PCB took on of the tabs with it, as you can see in the photos.
it does appear to be melted or burned on the inside. bending the tabs to remove the metal cover however turned out to be too much for the tiny switch. im guessing because the plastic was melted/burned was the reason why it started to crumble in my hand, so i took as many pictures as i could from when it started breaking to everything finally disassembled.
hopefully this will help in identifying the type of switch this is so i can order the replacement. thank you very much for the help.
Hello,
i replied to an other poster in the thread but i figured id notify you as well.
it was definitely burned or melted as when i tried to take it apart as i was instructed, it began to crumble in my hand. i tried to document every step as i attempted to fully disassemble it and hopefully i gathered enough photos to help identify it.
let me know what you think. i hope i didnt destroy it beyond recognition but if i did, i would have to figure out what switch would be a possible replacement for this to get it up and running again.
thank you very much for the help
Hi DuctTape88,
Based on the images you provided, I’m 90% certain it’s a DPDT switch.
Here’s a link to a pared-down list of DPDT slide switch options rated for at least 6A @ 125V AC. I don’t believe any of them are rated for higher voltage than that, so if you are running higher voltages, these won’t do.
What I would do is get some good dimensional measurements of your switch, especially the contact spacings on your circuit board, and then start cracking open the datasheets of the parts found in the link I provided to see if any of them might be a decent match.
hello,
thank you very much for your input. your link helped me narrow down a few selections. i also decided to try searching on google using key words from the link, the Acronym “DPDT” that you and others have suggested and the ratings on the switch and i believe i may have found to the one i have (or at least it looks similar.) i found some weird brands that i never heard of nor is it listed on digikey as a manufacturer (UXCELL seems to be the brand)
maybe it makes sense that the configuration is an on-off-on? (one side for AC and the other for DC with the Center for OFF). that im not sure, but the dimensions appear to be quite similar, i cant measure exactly as all i have is a ruler to eyeball the measurements. also, the actuator (or the black part) seems to be small enough to suggest three switch configurations when you slide it left to right.
i tried looking through the datasheets on multiple items but the list became narrower when i threw the new switch function in the filter (only gave me like 5 switches rated for 6a 125vac only, no 3a 250vac. i can find some with on-on though.) and the tabs on the bottom are rotated at a different angle than what is on the original slide switch.
either or, with this information, im going to grab a few switches and try them out. thanks so much for the help
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As far as I know, UXCELL is a distributor of low price components from China. The few times I’ve encountered their products I found them to be the typical low quality parts that are used in short warranty consumer electronics. Basically they are the same generic parts sold on the Alibaba and AliExpress but sold via Amazon.
How many click stop positions did the switch have before disassembly, two or three?
Based on the photos, the mechanicals look like a two position switch to me.
If it had 3 positions it is a DPDT ON-OFF-ON switch.
If it had 2 positions is is a DPDT ON-ON switch (the most common version).
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