Solder Used In High-End Computer PSU's - Page 1
Forum section: electronics / general

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: July 25, 2012, 05:52:07 am
content: So I had a Silverstone DA750 power supply on my bench today. In order to pull a single cap, it took the combined heat of my hakko 808 and my pencil iron set to 500c (and it was still challenging).Anyone here familiar with which type of solder they use it these psu's?

author: Psi
author_rank: Super Contributor
timestamp: July 25, 2012, 06:17:57 am
content: I doubt it was a solder issue, probably a large ground plane stealing all the heat away.Or maybe the hole was only 'just' large enough for the component, making it jam in the hole.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: July 25, 2012, 06:25:29 am
content: Quote from: Psi on July 25, 2012, 06:17:57 amThe holes were smallish but not too small, the solder simply wouldn't melt, even after adding fresh solder, it took both irons to get any component to budge on that board. Strangest thing, really. I wonder how much copper is in the pcb...

author: digsys
author_rank: Unknown
timestamp: July 25, 2012, 07:48:36 am
content: Quote from: StubbornGreek on July 25, 2012, 06:25:29 amOn high power PCBs, I use 8oz of Cu, 4Top/4Bottom. ONLY our JBC High power iron with a 6-8+mm tip will solder componentseffortlessly. Is it as hard to solder as desolder? If so, they most likely use 3+ oz Cu.

author: Balaur
author_rank: Unknown
timestamp: July 25, 2012, 08:40:30 am
content: I personally find that a bigger, shorter tip is crucial in ensuring good heat flow and thermal stability.I don't think twice before using my 60W Weller iron or a generous 3-4 mm tip (50W station) on big stuff. Makes a world of difference.Cheers

author: T4P
author_rank: Super Contributor
timestamp: July 25, 2012, 10:26:41 am
content: Grab a 6mm tip and blast off, how else can they provide couple of amps at 12v?

author: Zad
author_rank: Super Contributor
timestamp: July 26, 2012, 02:45:35 am
content: Those old fashioned "soldering gun" irons were excellent at that sort of thing. 200W, instantly.

author: pickle9000
author_rank: Super Contributor
timestamp: July 26, 2012, 03:36:46 am
content: It's all about the mass, this is my 80 watt iron, it's used for stained glass. I have a 140 watt one as well but it's packed away. Takes about 3 minutes to heat up. The tip is 3/8ths of an inch iron clad.These things get hot but not that much hotter than a normal iron the real power is in the massive heat transfer capability.Stained glass a good hobby for anyone involved in electronics, it involves soldering....mike

author: IanB
author_rank: Super Contributor
timestamp: July 26, 2012, 06:45:44 am
content: Quote from: StubbornGreek on July 25, 2012, 05:52:07 amThis effect is often reported and I've noticed it too.It's kind of odd because if you add fresh solder to the joint it melts easily, but if you hold the iron to the existing solder it just doesn't want to melt at all. It certainly seems like some kind of high melting point solder is used.

author: amyk
author_rank: Super Contributor
timestamp: July 26, 2012, 07:25:27 am
content: Quote from: IanB on July 26, 2012, 06:45:44 amThat's due to heat transfer (or the lack thereof). Old solder is going to have an isulating layer of oxides/dirt/etc., and because it's a solid, and so is the tip of the iron, there little area for heat transfer and it's not very effective. Some molten solder on the iron tip can conform and adhere to the surface of the existing solder, greatly increasing heat transfer.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 26, 2012, 07:53:42 am
content: QuoteThat could also be due to the original solder being leadfree, which has a higher melting point. Flooding a leadfree joint with leaded can make rework a lot easier.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: July 26, 2012, 09:14:35 pm
content: I'll tell you, that took some work... It took tons of fresh solder, not to mention that I warmed the board to boot. The combination of small through holes, high temp (and I'm pretty confident, lead-free) solder and lots of copper in the pcb made this thing harder to de-solder (heat-wise obviously not size) than just about anything I've worked on before.I would really be interested to know the specific type of solder used.

author: G7PSK
author_rank: Super Contributor
timestamp: July 27, 2012, 11:11:40 am
content: I think the problem is due to lead free solder, the tin absorbs a large amount of copper over time and with heat and the solder turn to a form of bronze. I have the problem with power sockets on laptops not even my 240 watt iron will melt the solder I have ended up cutting the sockets off and drilling the remains out.

author: T4P
author_rank: Super Contributor
timestamp: July 27, 2012, 04:11:07 pm
content: Basically it's a pain in the arse.