Help with desoldering

[littlerick]

I got my 4780 kit yesterday, and pretty much got it built.... However I ended up putting ALL 16 diodes the wrong way round.

I have been trying to remove them for a couple of hours now and havnt got 1 out yet.

All the pins are still on as I didnt snip them down before I realised i went wrong.

Would I be better off snipping them down to remove them or has anyone got any suggestions. I have a desolder tool, but still not coming free.

Its my first go at soldering a pcb, and now my first go at desoldering... Soldering went ok!

[c2cthomas]

Originally Posted by littlerick

Would I be better off snipping them down to remove them or has anyone got any suggestions. I have a desolder tool, but still not coming free.

This link should help. http://www.hardwaresecrets.com/article/164

You would be better off cutting off the excess lead as they do act a a sink and absorb heat that is needed at the solder joint. Use a heat sink http://www.radioshack.com/product/in...ductId=2103242 to protect the diode from getting to hot and don't stay on the joint for to long as you will run the risk of damaging the diode or the circuit board trace.

[littlerick]

Thanks mate.. I'll give it a go.

[c2cthomas]

hemostats work well as a heat sink too. hemostat, great deals on Sporting Goods, Business Industrial on eBay!

Seeing as how you are a bit new to this part of soldering I strongly suggest that you get some good safety glasses and use them. Solder can tend to "spray" around when pulling out component leads and hot solder in the eye is not recommended. I never had that happen - but I have had flecks of solder hit my safety glasses! BTW - you can remove the excess solder flux with alcohol (not the good drinking type) and a short bristle brush Acid / Flux Brush (24) 3/8" Brushes Solder Art Fluxing - eBay (item 370294177217 end time Dec-20-09 17:10:51 PST). Dispense the alcohol from a small pump bottle 2 x PCB flux Cleaner Alcohol chemical dispenser - eBay (item 120493964925 end time Dec-16-09 06:08:56 PST)

[wintermute]

I'd also get some desoldering braid. I use a solder sucker as a first pass and then soak up the rest of the solder with desoldering braid this youtube video will give you the idea. It is much quicker if you have used the desoldering tool first. Also I would cut off the used braid much earlier than in the video

Tony.

[Juergen Knoop]

see, if you can source some flux too. It is a great help with desoldering tools and braid
regards

[littlerick]

Well.. Ive been at it all day... 2 of us in fact. Managed to get 6 out but lost a few pins along the way. I'm hoping I can get enough to grip afterwards..

Just a little warning to other noobs like me... READ INSTRUCTIONS!!! then READ EM AGAIN!
and keep reading while you do it... Pictures are good as long as they are the same kit you are building.

Peter Daniels has been great with helping me get started, and errors aside I'm hooked and will definatly be doing some more.

[ricortes]

FWIW: I use a multiple step process with one of those Radio Shack rubber bulb style suckers and solder wick for when you can't get a good seal with the sucker.

After you remove as much solder as possible with the sucker and wick, just put a hot soldering iron to the pin and push it to the center of the hole. There should not be enough solder left to bridge the gap. Use a small screwdriver to keep the pin/leads in the center while it cools down.

Rick

[littlerick]

Update on the situation... I have managed to get 8 out of one board, with a mixed bag of success.

Four of the MUR's lot the pins in the process.. I still have the section of the pin that sits above pcb. Will I need to replace them or is there a good technique to bodge them into place.

Another option I may have is... Peter told me that if I reverse polarity when I connect it up it will still work ok. I have one rectifier that I havnt removed any MUR's from. Would it be possible to use the one rectifier to power both amps.