How I Killed My SVF Filter Board

Tried to solder too many resistors at once, zoned out and did not notice that two had slipped while I was soldering. Flipped board over to discover that two resistors were raised about two inches above the surface. That’s not the worst part - I made a total mess of trying to fix the mistake. I should have come here to ask for advice, instead I made it worse and now have holes stuck with cold joints!

The annoying thing is that the soldering itself, the thing I was most concerned about, was fine. Should’ve taken my time and done just a few resistors at a time. A lesson learned anyway! Next time I will do it with painstaking care and attention, just have to wait for the filter boards to come back in stock :slight_smile:

Holes full of solder? that’s not terminal. Get a solder sucker and try to suck the solder out. If that doesn’t work then heat the pad, apply more solder and then use the sucker again (the extra solder helps it all come out).

no sucker? no problem! Heat up the solder then quickly bang the board down (solder side down) onto your table. It should remove the excess solder.

if a solder filled pad would stop me i’d only get 0,7% of my projectd finished…
google for desolderinf braid, desoldering pump and listen to the guys that are way cleverer than me above

^ what qp said, except that you should not be wearing shorts.

Don’t cook bacon with your shirt off!

Hmm, well, I tried to desolder with my pump and I didn’t have any luck. The trouble is that there is a very small part of resistor lead stuck too, it seems firmly wedged in. I haven’t tried the add more solder and bang approach… Isn’t it likely that all my poking and the heat from the iron will have damaged something?

Dare I believe that all may not be lost? :wink:

Edit: I didn’t explain that the small bit of resistor lead is there because I clipped on both sides. I’ve tried heating the solder on both sides, poking the end through and even clamping the lead with pliers and gently pulling while heating - no movement! What have I done? I could post a photo tomorrow if helpful.

@wuh for future reference, I find it useful to stick components down to the top of the board with sticky tape or masking tape before soldering. Works nicely for rows of resistors.

a|x

I’ve found that resistors don’t typically need to be bent to stay put. I leave the leads straight in case I need to remove something later on. For ceramic caps, I drop them all in then take a piece of cardboard or cardstock, place it over the board and flip. Nice and straight leads. When its time to remove, I always use solder wick. Sometimes, when things get stuck, take a cut piece of a component lead (the thicker the better, like the 4001 diode or Arduino header), grasp it with pliers and use it to push the stuck part through while heating it with your iron. Occasionally the pad will die though. Easily fixed with a small piece of wire jumped to the next point in the trace.

Godspeed.

As long as there is no short anywhere you could just leave the piece of wire in the hole and attach the new resistor on top anyway. Not very pretty but at least it should work.

If you want to remove something that is stuck in a solder hole, heat the pad, and stick something like a syringe needle(or any stainless needle really) trough. Since the stainless steel wont adhere to the solder, it is a quick and relatively easy fix. Be aware of the fact that the needle will heat up really quickly, so you need to hold it with gloves on, or in a vice or something like that.

Seconded, use a needle. It’s never easy but it’s part of the learning process, you soon remember to check and double check so you don’t make mistakes :slight_smile:

How is that tool called fcd72?

That’s a dental explorer. Here’s a page full of torture devices

Its good for all kinds of inspection wether it is bad soldering or caries. which is from a functional analogy point of view pretty much the same, hence you can use the same instrument.

I tried again tonight, no luck. I think because I clipped the lead on both sides and the legs had been bent a bit, the lead is just 100% stuck. When I hold the iron against the pad, I don’t even see any solder melting, I think it’s mostly just the leg of the resistor in the hole and there’s nothing I’m able to do that makes it budge. I think it would have been something I could rescue had I not clipped on both sides. It seems ridiculous that I did that in hindsight.

Unless anyone has any other creative ideas, I think I will swallow my pride and try again with a new board and replacement parts which I’ll need to source myself.

Sometimes if you add some new solder, the old solder will melt easier, I have no idea why. If I have one that is really stuck, rather than heating the crap out of it and risking removing the solder pad, I flatten one side of it and just drill it out with a small drill bit and a Dremel.

Add new solder. Try again. If not successfully, let everything cool down and try again. Don’t rush. Don’t overheat the PCB.

This: