help) my laptop is damaged by over voltage... - Page 1
Forum section: electronics / repair

author: hiocks
author_rank: Newbie
timestamp: May 29, 2020, 06:31:09 am
content: first, i'm not nation using english.excuse for my english.my laptop is damaged by overvoltage maybe.it should needs 5V, i connect it 12V.. ofcourse, ampare is different.so, i drived my laptop on high power.at time connected, there was small spark and burnt smell.i took out charging jack immediately.and i took to peices.one tiny part of ic panel is burnt.i think that is a part of safe circuit.i can turn on my laptop nomally but not charging.maybe... i think motherboard and most of circuit are alive, only safe circuit is dead.in my local, repairman say that cant be repaired.however i want to find way.the way i seek for that part ( maybe that is fuse..? ) and i solder it is impossible?help me.if you need, i can upload picture of my laptop ic panel ( burnt part )

author: brabus
author_rank: Frequent Contributor
timestamp: May 29, 2020, 07:05:00 am
content: Hi!Yes, a picture would help us a lot in order to formulate a diagnosis. Can you post it?

author: george.b
author_rank: Frequent Contributor
timestamp: May 29, 2020, 07:13:02 am
content: Also informing the laptop make and model could be useful.

author: hiocks
author_rank: Newbie
timestamp: May 29, 2020, 09:40:32 am
content: thank you for you answer.this model is unknown and brand too..... just cheap chiness notebook...name is : realbook 15and added picture. what is name this component?

author: brabus
author_rank: Frequent Contributor
timestamp: May 29, 2020, 10:32:08 am
content: I'd say it looks like a capacitor. Maybe tantalum, maybe polymer, it doesn't matter: if you remove it and no further damage is on the board, the laptop should come back to life.If the board is completely dead, there must be something else broken on it. I would start checking the SMD fuses, there may be a bunch of them scattered on the board.Step 2: follow the voltages. Start with the DC barrel voltage and see if it's interrupted at some point. Same goes for the battery voltage.Most probably a PMIC has given the magic smoke.

author: hiocks
author_rank: Newbie
timestamp: May 29, 2020, 11:17:08 am
content: your answer is very nice! thank you 넌 최고야excuse me... can you explain why charging board part have capacitor? im very very beginer...i know only...capacitor save the current and shot all of them or adjust same steadly.there is other rule??and should i remove that? there is any problem??exactly board is not gone. i can trun on laptop. and can start windows, play or excute some app/program.i didnt charge laptop yet... just scared ㅠㅠ

author: brabus
author_rank: Frequent Contributor
timestamp: May 29, 2020, 04:45:42 pm
content: Hi,Capacitors are used for many reasons; in a power stage they are generally used to keep the voltage stable by providing a charge reservoir for quick current delivery. Keeping the voltages stable helps reducing the EMV emissions.In your case the capacitor seems (be careful: we are only looking at pictures, so no diagnosis can be 100% certain) to be just connected in parallel with the power input.Before doing anything else, you should check if the capacitor is now short-circuited (just measure the resistance in both ways using a multimeter). Then remove it and check if the short is localized in the condensator or further in the circuit.Then, you can try supplying the laptop with the correct 5V jack, or even better you can provide the 5V using a current-limited power supply. Start very low, like 100mA or less, and work your way up to the maximum current, i.e. until the current stops increasing upon increasing the current limit.In order to set a reasonable current threshold, look at the power supply. How much current should it provide? Let's say 5V 2A. You set the power supply at 5V and 2,20A max.; if the current keeps increasing, there is someting wrong.If, instead, everything works fine, well… the capacitor is the only victim, you have been very lucky! :-)Once you can confirm the capacitor is the only broken part, we can look for an adequate substitute.Do you feel confident desoldering such a capacitor?