Tips for Recapping Power Supply Traces

[bgavin]

Are there any words of wisdom about recapping PSU boards?

I got into one, and noticed the trace lifted off the board during the process. I was able to get the part soldered back into place without ruining the trace... but it was unnerving.

Motherboard capping seems to be much easier. PC board traces seem to be very fragile.

Thoughts?

[Spacedye69]

Re: Tips for Recapping Power Supply Traces

Working on consumer products, ie TVs, dvd players, etc, is even worse. Use low heat and remove all the solder before you try to remove components seems to help. I use solder wick all the time on single layer boards and it works well to get all the solder off the trace before you heat the component leg to remove it.

[gonzo0815]

Re: Tips for Recapping Power Supply Traces

The difference is caused by the lower quality PCB material used in usual consumer products like PSU`s. It is in most cases simply hard paper which delaminates easily and is not that forgiving regarding to high solder temperature and soldering time.

Just do not use to high temperature and keep soldering time short.

[starfury1]

Re: Tips for Recapping Power Supply Traces

Id agree with the above,
You also have to get use to working with them and that can only come with perfecting your techniques with practice so get some junk stuff if you can
(this would probably help you determine what the pcb you are going to work on is liable to take)
At lest with a single or double sided PCB you can repair a damaged trace without too much trouble

But at times it does happen, damaging traces

example;
If you are removing IC's its probably easier
(if you know you can get the device at a reasonable price like an op amp)
just to cut the legs at the body them remove the legs one at a time.

So there are different ways to approach the problem depending on what you are removing and judgment calls on what you think the PCB will stand heat wise etc.

Although its always nice if you can get something out in one piece.

The thing I was taught was
"destroy the component if you have too, never damaged the PCB"
(but it does happen regardless of how careful you are sometimes)

on lower quality PCB's too much heat is really the enemy

lastly sometimes having the right tool for the job just makes life so much easier, but in this game that can mean a lot of $$$$

Yeah I know the feeling when a trace lifts

Just my thoughts on it

Cheers

[Krankshaft]

Re: Tips for Recapping Power Supply Traces

Sometimes it can't be helped if the traces are pure crap then its going to happen.

A way to avoid it is to melt the solder lift the caps leg up and snip it flush with the board that eliminates the bent over lead from pulling the trace out when you try to tilt the cap to remove the lead.

If you do lift a trace do what I do scratch off some solder mask off the track itself with a razor knife until you get down to the copper.

Insert the cap through the hole and bend the lead over positioning it right over the copper track snip the rest of the leg so that it is only as long as the area you scraped off the solder mask. Then solder it down.

If you're working with 2 layer boards the same applies most likely the cap is only connected on one side of the board or the other so tracing the vias is relatively easy.

However if you are working with a multilayer board (3 or more layers) you better have a schematic or you're screwed.