KSGER T12 Soldering Station Front Panel - Page 1
Forum section: electronics / repair

author: Tinynja
author_rank: Newbie
timestamp: June 27, 2021, 11:37:01 pm
content: Hello, recently I tried to "fix" a device which was connected to mains (learned from my mistake), and when I touched a part of that device with my soldering iron, a big spark was generated, my soldering station died, and magic smoke was released inside of it.After opening it, I noticed an exploded 35V 1000uF capacitor and replaced it with something similar (50V 470uF) just to see if I could get some sign of life out of it. Sure enough, the main board seemed to correctly generate the 24V output.However, the front panel doesn't want to light up, which renders the soldering station useless for now. I don't know too much about electronics, so I'm not sure what I should be looking for. Here's what I've done so far:- Multimeter in continuity mode suggests there is a short between VCC (not 24V+) and GND, which I guess is the supply for the STM32- Some voltage injection in constant current mode to try and determine where exactly the short is, without much success (low quality tools)- The (what I assume to be a) buck converter with the JW5026 doesn't seem to be generating any voltage, I'm not sure if it's because of the short or if the buck itself is broken?I've posted a few pictures in attachment, in order: whole soldering station, front panel, labeled components, CC voltage injection.Could someone please help me figure out what's wrong with my soldering station? All help is greatly appreciated!!!

author: RayRay
author_rank: Frequent Contributor
timestamp: June 28, 2021, 04:37:50 pm
content: Honestly, can't say I'm surprised nobody replied to this one! I've considered not to either, for obvious reasons.The only thing I'm gonna say is that you should call it quits on electronics repair! Attempting to repair or use a soldering iron on a live circuit is plain idiotic and dangerous, and you could've easily gotten electrocuted if you were less fortunate! And you definitely have a lot to learn about capacitors if you think 470uf is "simiar" to 1000uf. That's all I wanted to say really. Typically I'd offer assistance instead of criticism, but since you seem extremely reckless and irresponsible, I'm gonna refrain from doing so. Good luck to you, but again, I don't think you should fiddle with electronics, sorry.

author: Tinynja
author_rank: Newbie
timestamp: June 28, 2021, 06:17:36 pm
content: Hey there thanks for your response! I appreciate your concerns, and I understand somebody more knowledgable than me wouldn't have done the mistakes I made.However I think I'm a human being well capable of learning, so I'll make sure to do more research on the safety basics regarding electronics repair, which I sure don't have as of now, in order to be able to continue fiddling with electronics safely.As for the 470uF capacitor, I know it's definitely not similar to 1000uF, which is why I'll replace it with the correct one as soon as the part arrives, but since I wasn't gonna put any load on the PSU, I figured it would be good enough as a proof of concept, which it did.Finally, for the front panel, I tried more voltage injection and it seems the STM32 is the only component heating up, so I'll try desoldering that to see if the short is gone.

author: RayRay
author_rank: Frequent Contributor
timestamp: June 28, 2021, 08:10:25 pm
content: Wow, you're definitely taking it better than I thought! And to say that a more experienced person wouldn't have made the same mistake is quite an understatement. I mean, yeah, people can make mistakes, but I'd say this one goes more to common sense. High voltages can literally kill you, and you thought it'd be a good idea to poke around with a soldering iron on a live circuit? That's just incomprehensible to me. For future reference, the only thing you're allowed to do on a live circuit is to measure voltages with a multimeter (and that's if you know what you're doing, being careful, and using one with proper input protection) Anyhow, I'll admit that initially, I was shell shocked from reading what had happened (as you've risked your life doing something very unsafe, taking high voltage for granted) but I'm willing to go past that now (just be more careful in the future, because again, your life literally depend on it, and if you'd get electrocuted, things might not end well!). And for the record, electrolytic capacitors have a 20% tolerance up or down, so you should never replace a 1000uf with 470 (as that's way below) and even if you think it helped with diagnostics, it's just not right way to go. Also, LOW esr/impedance caps are generally used in these type of circuits (so using caps made for general purpose use isn't a good idea). Anyhow, 99.9% of these T12 controllers can accept 12-24V, so you could use a laptop ac adapter or a 12V adapter to test things further, and as long as you're just gonna use it to test the display (without operating the iron) current draw shouldn't be an issue. Provided the adapter has a DC jack, you could just desolder the red (positive) and black wires from the power board, shove the red one to the inside of the jack, and clip the black to the outside of it with an aligator clip (check the polarity symbol on the adapter itself first though!) most of em have the positive on the inside. Doing this would tell you if the issue is with the controller or the power board. Good luck