/diy/ - Do It Yourself

>>2517594
Power supplies are not the place to start learning about electronics. I've been doing electronic repair semi-professionally for a decade and I still avoid opening one of those fucking things if I can avoid it. The PFC system in virtually every PSU made after 2010 makes it extremely difficult to know if the system is properly discharged, and one wrong move can easily kill you (not the meme fork in 120/240v outlet type of kill you, the several kilovolts type of kill you)

>>2517594
what goes through your mind?
>ima take picture
>click
>huh I can't see anything in this
>welp good enough ima upload it.

>>2517594
>>2517691
OP as this anon said >>2517691 , I wouldn't go for PSUs as my first repair, but if u have the guts and the brains why not...
so here are the 3 golden roles of PSU repair:

1. never under any circumstance work on it live or connected to the power cable!!! keep the board outside the unit completely unconnected to anything while working on it!!

2. always double check the safety off the board, especially if recently powered or if it is connected to high value capacitors that operate at moderate to high voltage (100v-2kv+), these can pack a strong punch sometimes enough to vaporize a man!!
https://www.youtube.com/watch?v=coW1RHUsf_I

so make sure they are discharged b4 u even think of working on the board!!

3.look at the board carefully, give the board a smell check and if u notice a burned smell or see a component that looks charred or cracked or burned or blown then replace it.
check for common culprits, like switching transistors and diodes, tantalum caps, electrolytic caps, thyristors, Opto-isolators and the such like since they tend to fail first and be the most stressed in operation (here i assume yk how to test them).

once u did that u can start actually repairing and diagnosing the board, i prefer to look at the mains side first, since it tends to be the simplest to diagnose, check the x and y class caps, movs and ptcs, working ur way down stream...
I am the OP from the fixinga thread, i really love seeing anons trying to fix instead of endlessly consuming, just follow the golden roles and don't kill ursellf!!!

>>2517691
>>2517734
Visually the only thing wrong with the board is this blue thing appears to have plastic missing. Based on that video I’m gonna assume the loud pop I heard was the capacitor discharging through it? It was loud like the video. Anyway I found a fuse rebuild kit online for this specific model that included the blue things. I guess I’ll need ti order a soldering iron too.

>>2517775
Soldering iron, solder, a bit of solder wick (to draw away the old solder when you remove it), replacement part, yeah.
As the others said, remember that capacitors can hold charge even after disconnecting from the mains, so probably throw in a high-resistance power resistor to short across any bits of circuit you will need to touch to do the job. (but I don't have the guts to fuck with PSU shit)

>>2517775
id also check that mosfet transistor too

>>2517775
Looks like a MOV (metal oxide varistor). They tend to fail like that, it's a safety feature, but it also may indicate an overvoltage issue elsewhere.
Simply replacing it will likely fix the issue, if not it will fail again.

I had a MOV burn out in my heater because of a loose power cable elsewhere in the house causing voltage fluctuations and the MOV was absorbing it.

>>2517805
Nevermind me that's a cap according to the symbol. I'm retarded.

>>2517806
Yeah, fucking love the older boards that were built for humans to assemble them and could space things out and add proper labeling.

>>2517775
capacitors blow up for a reason, just replacing it may not fix it.

>>2517775
nice job anon, make sure u get the same type of cap and ratings...


>>2517799
for de-soldering, I would highly recommend using a solder sucker/pump like a goot GS-108 or TP-100 which will generally work much faster and stress the pads less from my experience especially for someone who never used solder wick b4.
also might want to watch these first before u start if u haven't soldered b4:
https://www.youtube.com/playlist?list=PL926EC0F1F93C1837

https://www.youtube.com/playlist?list=PLBXXuFXCtmtqlamIEfu3lSTzM5t1k2cx_

https://www.youtube.com/watch?v=M0wI-5YZQm4

https://www.youtube.com/watch?v=vpgMn88Qfjs

follow the steps and complete the primary check/repair, then you should go for a secondary diagnoses, which has 3 golden roles:

1. during this stage u will have to power up the board, the best way to power it is an isolation transformer, so the board is kept floating (galvanically isolated) this will reduce the risk of electrocution, also install a fast acting low current breaker or an incandescent lightbulb/heater or a fuse inline for added safety against short circuits accidental and otherwise, i personally use a 200w ceramic heater it if it glows i know there is a short and due to the PTC nature of the heater it limits the current enough to not cause catastrophic failure...
u could work on it on that state, but still i wouldn't recommend that for a beginner, so wear gloves and boots while working, and if u don't have access to an isolation transformer u have to use a GFCI/RDC outlet or breaker in line with circuit u are powering:
https://www.youtube.com/watch?v=olq9wdeNS4c

2.make sure yk where ur hands are!! keep ur hands off the board and the board always powered down at all times except during the test!!!


3. thou shalt check voltages, start from the primary side, since the voltages there are known for the most part, if they are in the ball park (+10v or -10v) its ok, any thing higher u should investigate the primary components

>>2517775
I am not sure what those two leads are right next to the cap, but they both probably need to be replaced

>>2517594
find the board that has the burnt/blown component. get serial number of the board and replace.

>>2517807
>older boards
wait until you see the underneath of ops board

>>2517775
The blue disc it's a MOV, you can search on digikey/farnell/etc.
From my experience repairing the Samsung power supply I ended by changing all the electrolytic caps. big or small. All of them were out of specifications.

>>2521010
>The blue disc it's a MOV,
symbol on board is for capacitor
id as C P819

>>2521023
>symbol on board is for capacitor

>>2521023
Yes, it's possible that too to be a C-Y cap. Anyway will be a good thing to search for the schematic to be sure.

>>2517594
Which model of Samsung? Check on the back label.

>>2521050
>Anyway will be a good thing to search for the schematic to be sure.
Yep and there's usually a parts list too. If OP isn't familiar with X and Y safety caps, this document explains their purpose and markings https://pdfhost.io/v/CKWYZVLUf_SAFETY_CERTIFIED_CAPACITORS