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Installing Capacitors how to locate the capacitor on reverse of board Answered

I am trying to install new capacitors on a PCB ,  I know which capacitors to replace from the capacitor side how do you find the pins on the reverse i see the code number but there are so many pins arounf this number im just not sure and its not on an outside edge either ie first in line.  Can anyone suggest how to confirm the right pins to desolder.



It's one of those thing which gets easier with practice; Once you get your eye in you'll be able to go straight to it just by holding the board edgeways and rocking it from side to side.
If it's failed electrolytic capacitors you're replacing (I've done hundreds in my time) I've found the easiest way of getting these out of multi-layer boards is by heating one leg to melt the solder and rocking the capacitor one way, wait a moment then heat the other leg and rocking the other way, then repeat until the capacitor comes free. This will also confirm that you're working on the right component.

Also, don't forget that electrolytic capacitors must be replaced with the right polarity so make a mental note of which was the positive terminal and which the negative terminal when you take one out.  Different manufacturers use various methods of showing the polarity so work out which method is used on your board.

There is about a hundred different ways to do it.

Try this one.

Look down the circuit board from its edge and line up with a pen or your soldering iron.


thanks Joe never soldered before but learning fast with the help of people like you

No problem we are here to help.

Another thing you might want to try is practicing on old unwanted electronics like a transistor radio watch out for the high voltage on TVs and monitors, they can kill.


Count the pins or take a measurement of the part from the edges of the board. If the board is silk screened then capacitors are often labeled with a C and a number. It shouldn't be that hard to deduce. Even if you desolder the wrong pins you can always solder them back.

thanks for your prompt help many thanks. The only doubt i really have now is the wattage of my iron iv got a 40w mains powered is this too high for the job or ok

No it's not too high. Just don't keep the iron on it forever.

thank you for your reply i am replacing Samsungs dodgy capacitors in a flat screen LCD, I am a total novice to soldering i know basics and have all the gear here to do the job its just having the guts to proceed, gona have to bite the bullet and do it. Yes i can see the corresponding number on the reverse of board are the pins normally to the right of the number on the reverse or below etc. Thanks for your reply

There is no standard orientation. Just do it. It's already broken so your not going to hurt anything.

It just takes practice... keep trying and be patient. it helps to have good lighting in your work area too.