Monitor PSU circuit board question

[Davejr]

What are these? (As noted with the red lines pointing)




And, is it absolutely imperative to maintain this gap? (as noted with the black lines) [also note that the blue dots indicate the leads of one of the capacitors that I will be replacing]

[Pentium4]

Re: Monitor PSU circuit board question

It's not imperative to leave the gap but I think it's best to leave it how it came, with the solder maintained

[mariushm]

Re: Monitor PSU circuit board question

It's just extra solder applied on the copper traces so that the pcb can carry more current through the traces.

copper trace heats less due to more metal on it.

The black lines (and the coating over the traces) are there as a sort of blocking mechanism so that the solder attaching to the lead won't just get in contact with the other solder, the island on the trace. If it did happen during soldering, the solder on one side could suck the solder on the other side, for example the lead on that component could be poorly soldered because the solder moves to that island of solder.

[Davejr]

Re: Monitor PSU circuit board question

I added those parallel black lines in photoshop to aid in the question. That gap, and several others, is extremely narrow. Keep in mind that the lead spacing on the caps is 3.5mm for reference.

[mariushm]

Re: Monitor PSU circuit board question

I didn't even think about it. Sometimes there are such lines on pcb made using silkscreen.

The idea remains the same.

Picture it like this. The board is sprayed with a liquid flux, then it's attached to a conveyor belt by the corners and goes inside a machine, over a bath of liquid solder.
Anywhere there's flux and bare copper, the liquid solder comes up and gets attached.

There are however things such as surface tension and other. Basically after solder covers the whole copper island on the trace, it tends to shrink towards the center of the trace reducing its size. If there was no separation between the round pad and the copper island, the solder could go towards the solder island and the lead of the component could be partially unsoldered or poorly soldered.

Also, there's an issue of the larger copper trace dissipating heat better (so there's more time required for solder to adhere to the copper) compared to the round pad and the lead.
On the round pad and lead, solder heats them up fast and goes up the lead and forms a nice solder job on the bottom and the top (if it's a double sided board). With the large copper traces, it takes more time for the solder to cool down and solidify.
If they were together in a large blob, the component soldered there could be affected from the heat of the chunk of solder cooling down on the traces.

Here's a good example of how these boards are soldered : http://www.youtube.com/watch?v=inHzaJIE7-4

[Davejr]

Re: Monitor PSU circuit board question

So I just need to solder as carefully as I can, but if I should accidentally 'bridge' that super tiny gap it shouldn't blow it? All the vids I've watched on youtube make it look easy without that much precision in the soldering.

[Pentium4]

Re: Monitor PSU circuit board question

Yeah you will be fine.

All the vids I've watched on youtube make it look easy without that much precision in the soldering.

It depends on the board somewhat too, and the solder that you use.

[lexwalker]

Re: Monitor PSU circuit board question

What are these? (As noted with the red lines pointing)




And, is it absolutely imperative to maintain this gap? (as noted with the black lines) [also note that the blue dots indicate the leads of one of the capacitors that I will be replacing]

Those actually have two functions. For the first one, they act as passive heatsink on the PCB (to dissipate the heat). For the second one, it allows more current to flow thru the traces (you can commonly see this in high current computer PSUs also)..

[Davejr]

Re: Monitor PSU circuit board question

Thank You! You guys have been very helpful.

[Lumberjack777]

Re: Monitor PSU circuit board question

is it absolutely imperative to maintain this gap? (as noted with the black lines) [also note that the blue dots indicate the leads of one of the capacitors that I will be replacing]

OK, they answered the other question but to answer this question....
The black lines are on the same copper trace or conductive pathway (inside the red). You don't have to worry about a "gap" there. In fact if a person was to lift a trace where the component is soldered in; they might need to connect to a component nearby on the same copper trace or conductive pathway.

BUT......where you have the 2 blue dots for the leads for the capacitor: that gap needs to be maintained. You'll notice they are on 2 different copper traces. Hope that helps.

[Davejr]

Re: Monitor PSU circuit board question

Thank you Lumberjack777. Yes it does. My soldering skills are 'ok', but I'm not a robot. That extremely narrow gap had me concerned when I was examining it. Used macro mode on the camera to take the pics. I do plan on practicing a bit.