Comments on The Recapping FAQ

[budm]

Re: Comments on The Recapping FAQ

Wattage is also important, to work on mother board, you will need 60 watts, you can have two soldering irons that can have the same temp, the lower wattage one will will lose it temp quickly when makes contact with the object you are trying to solder.

[ratdude747]

Re: Comments on The Recapping FAQ

I have to agree with this. I have a Hakko Soldering station that got out of calibration for a while. I was recapping an old stereo system and I burned up a couple of pads before I realized what was going on. It had to be up around 400 degC. Of course I haven't dealt with computer motherboards yet, but I just can't see setting the temp that high because I have been able to desolder everything fine at lower temps.

It's because motherboards often have large traces... like ground planes. and multiple layers of traces. they act as heatsinks, sucking away the heat put out by your iron. So yes, you do need to set it that high.

[bobbyrae]

Re: Comments on The Recapping FAQ

Hi.

I'm a new member, but I have a comment about the temperature recommended for soldering the caps. I'd say 450C is way too high. When I had my soldering courses (first halves of the 90's), a rule of thumb were approx 150C above the melting point of the solder. Since normal 60/40 solder have a melting point of 177-183C, a good temperature would be about 350C. If you need as high as 450C, either you don't have a powerful enough soldering iron or a too small tip. With too high temperature it's a lot easier to damage the tracks due to disbonding. Too powerful soldering iron/too big tip/prolonged heating is no good either...

Stig

I have to agree with this. I have a Hakko Soldering station that got out of calibration for a while. I was recapping an old stereo system and I burned up a couple of pads before I realized what was going on. It had to be up around 400 degC. Of course I haven't dealt with computer motherboards yet, but I just can't see setting the temp that high because I have been able to desolder everything fine at lower temps.

[severach]

Re: Comments on The Recapping FAQ

The cheapo solder stations don't have good heat recovery so they need to run at a high temperature to have enough heat to withstand the shock of cold parts. A good solder station can do the same work much better at a much lower temperature.

What I'd like to find is a needle nose with a curved jaw and a close spring. It would resemble some of the spark plug pullers and does not need to be strong. The jaw should be silicone tipped and thin enough that I can correctly position a cap in the middle of other caps underneath a wire bundle.

[stavr0]

Re: Comments on The Recapping FAQ

5.5. Remove the capacitor

Gravity is your friend: Resting the board upside down, I clamp the bad cap with a needle-nose plier with an elastic band around the handle. Heat up both leads alternatively every few seconds until it falls off under the weight of the pliers.

[Per Hansson]

Re: Comments on The Recapping FAQ

I solder at 350°C and desolder at 400-450°C

[StigOE]

Re: Comments on The Recapping FAQ

Hi.

I'm a new member, but I have a comment about the temperature recommended for soldering the caps. I'd say 450C is way too high. When I had my soldering courses (first halves of the 90's), a rule of thumb were approx 150C above the melting point of the solder. Since normal 60/40 solder have a melting point of 177-183C, a good temperature would be about 350C. If you need as high as 450C, either you don't have a powerful enough soldering iron or a too small tip. With too high temperature it's a lot easier to damage the tracks due to disbonding. Too powerful soldering iron/too big tip/prolonged heating is no good either...

Stig

[kc8adu]

Re: Comments on The Recapping FAQ

MCM offers a number of Tenma adjustable solder stations that are affordable to the hobbyist.

Could you experienced buys recommend what features are desireable for this level solder station? For example, I gathered that 60w + chisel tip are good. The Tenma stations are only 48w, and rated to 800F maximum.

the bargraph and digital versions are decent.
i own one each.
the desoldering station is fragile and maintainence intensive.
my old(antique) ungar is 10x better.

[bgavin]

Re: Comments on The Recapping FAQ

MCM offers a number of Tenma adjustable solder stations that are affordable to the hobbyist.

Could you experienced buys recommend what features are desireable for this level solder station? For example, I gathered that 60w + chisel tip are good. The Tenma stations are only 48w, and rated to 800F maximum.

[yanz]

i use tc "dental pic" method and it rocks! btw i use goot/taiyo solder iron... 40w is hot enough and i found no problem.

[willawake]

no can do. just throw it in the mods section and i will finish the recapping faq instead.

[Topcat]

You should be able to edit the post. Let me know if you cant.

[willawake]

ok agreed. For the people on low budgets, is a desoldering bulb the best choice then?

TC : i need to edit the "ghetto cap replacement tips" to remove reference to soldapults.

[kc8adu]

This is the only part I find objectionable. I HIGHLY recommend NOT using mechanical solder suckers on motherboards! I've seen many people destroy their boards with them, typically when it recoils and impacts the board, knocking the traces off or sucking the lead port out of the PCB. If you don't have access to a pneumatic or vacuum solder sucker, use solder braid or a needle pick. The pick works best for me, I can clear a hole faster with the pick than one can with a pneumatic solder sucker.

VERY nice writeup!

agreed on both counts.
btw i had to rework a board from a mitek edm where a previous tech had used a soldapult.
had a short on +5 he couldnt find.
turned out to be a crumb of solder lodged between 2 pins of an ic.
there are some things a soldapult is ok for.for everything else theres ungar,weller,hakko,ect.

[willawake]

hmmm, i guess you are right, there is a concern. I did every board with the solder pump though and there was no probs. i am holding it flush against the board and the board is supported by the board holder. then I hit the switch which makes suction against the board and then quickly take the iron off the back of the board causing the solder to get sucked through. there is no impact against the board but maybe the pressure with the suction could damage a trace. Indeed the lead port could get sucked out.

Perhaps we can put all the methods with their pros/cons/dangers in the faq

isnt there also danger in damaging the lead port with the needle pick?

guess i have to splash out on a rework station someday.

[Topcat]

Solder Sucker / Soldapult (Standard Size)

This is the only part I find objectionable. I HIGHLY recommend NOT using mechanical solder suckers on motherboards! I've seen many people destroy their boards with them, typically when it recoils and impacts the board, knocking the traces off or sucking the lead port out of the PCB. If you don't have access to a pneumatic or vacuum solder sucker, use solder braid or a needle pick. The pick works best for me, I can clear a hole faster with the pick than one can with a pneumatic solder sucker.

VERY nice writeup!

[willawake]

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