Dell Dimension 8400 V-Core caps

[LLLlllou]

Re: Dell Dimension 8400 V-Core caps

Well, I held my 2.4mm chisel tip on a nicely fluxed, filled solder hole for 4 and a half minutes of nice, glossy, 450*C, heat-transferring goodness, and after almost 5 minutes of continuous heat, the solder on the other side of the hole/board was still solid as can be.

I've never run into this before. Ready to toss the damn thing and get a board on eBay, but it's getting personal to the point that I'm not sure I can.

Any chance of using a drill bit or needle are out, regardless of whether I'd actually want to or not, because it won't soften up on the other side at all.

What's a guy to do?!?!?!?

8400 motherboards are probably THE worst to recap. As far as I can tell, between the two outside layers of copper, is an internal layer of metallic super cooled hydrogen. The only thing I've found that works well with this guy is TWO soldering irons at the same time. I have a 65 watt Weller as my usual iron, but when working on an 8400 board I rig it up with a couple pieces of 28ish gauge wire to either my 45 watt Weller or my other 65 watt Weller so the two tips are physically touching each other. Even then I have to set the temp to over 700 degrees for it to reliably melt the solder on the Vcore caps in anything under 20 minutes. I remember the first time I did an 8400 I thought there was something wrong with my iron.

BTW, on 8400s I either polly mod with 10 560UF 2.5V pollies, or replace all electrolytics with 1800UF 6.3V Panny FLs. A couple times I've done polly on both ends, polly in the middle and FLs on all the rest, never had one come back, and never had one fail 48hr Prime95.

[LLLlllou]

Re: Dell Dimension 8400 V-Core caps

560UF 2.5V pollies

Oops, meant 560Uf 4V pollies

[MRXISTRER]

Re: Dell Dimension 8400 V-Core caps

If solder doesn't seem to be coming out, usually I just keep on applying fresh solder and solder wicking until it comes up. If you are using solder wick, expand it so it's not so compressed. If it's still not coming up, realy lay into it with the soldering iron...get it hot, make sure you are touching the joint and move around the soldering iron a bit. If that doesn't work, try a pump.

Heat it up. There's a lot of copper for the VRM, so it's going to take a while to heat up. Minimum wattage is around 40W with a chisel tip. In combination with old hard lead-free solder, it can definitley be a pain. Make sure to apply fresh solder to the joint and use flux-core, and/or flux.

Use a small safety pin, opened up to 90 degee angle. Push and twist it through from the component side while applying heat on the other side. It clears a good path to re-insert new caps and the safety clasp, as-a-grip prevents finger burnning!