hello, Tl:dr At Bottom
I am novice when it comes to repair, and the item im 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 didnt, please do 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.
