I'm trying to desolder a couple compnents on a Korean DAC and cannot seem to melt the solder! The DAC appears rather well made commercially (Calyx) and I'm using an OKI Metcal PS-900 with Smartheat. The Metcal has always been very good about delivering the right amount of heat to the soldering task but I can't get the solder joint to melt. With a lot of flux and a good size tip wetted with 60/40 I can get it to partially melt for a moment but not enough to do anything with.
Is it possible a soldering method was used in the factory that is ultra high heat that a Metcal just can't achieve? If so, what are my options? Will a computer repair shop with Hotair Rework station be able to manage? The User Manual specs don't even specify the tip temperature range on the Metcal... that I can find.
Is it possible a soldering method was used in the factory that is ultra high heat that a Metcal just can't achieve? If so, what are my options? Will a computer repair shop with Hotair Rework station be able to manage? The User Manual specs don't even specify the tip temperature range on the Metcal... that I can find.
You can try using some lead based solder to dissolve the other solder. Just wet the joint with a generous amount of new low temperature solder and that might do the trick. If this does not work there are commercial solutions.
It's a combination of leadfree solder and copper ground planes soaking up the heat.
Try a larger tip or a tip with a higher temperature rating. Check the Metcal catalogue.
SMD board manufacturing is done with specific heat phases making it a bit easier for the solder to melt with larger copper areas or multilayer boards.
Try a larger tip or a tip with a higher temperature rating. Check the Metcal catalogue.
SMD board manufacturing is done with specific heat phases making it a bit easier for the solder to melt with larger copper areas or multilayer boards.
That's what I already did. No effect.
This is actualy a USB B socket. Yes, the solder tabs are big and attached to a large ground plane, but there is a good size solder joint where touching the 'wet' 2.4mm tip directly to the solder did nothing.
I was scared to use a monster 5mm tip on a PCB ...but that worked! Thank you.
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An infrared pre-heater can help, as can a hot air gun. These apply heat to the entire PCB to heat the inner copper planes, so that the entire thing gets up to reflow temperature. Solder still melts at a low temperature, and polymers still get destroyed at high temperatures, so using a hotter iron will eventually destroy the PCB or the components or both.
You simply can't get enough energy into the PCB through the externally visible solder fillets using any type of iron, so you want some other way to add heat (at a safe temperature) to the entire assembly to get it to reflow temperature. Google 'hot air rework' and 'infrared preheater' for some ideas on how it can be done successfully.
Best of luck!!
edit: I see you were successful, and it was because the larger tip transferred more energy to the PCB. Remember that temperature is the enemy, not the total amount of heat energy. Lots of energy gets everything to the temperature you want, and a larger iron indeed can do that. I still think a preheater and/or hot air gun will be the best route for next time, so it's still worth doing a search and see how that approach can work.
You simply can't get enough energy into the PCB through the externally visible solder fillets using any type of iron, so you want some other way to add heat (at a safe temperature) to the entire assembly to get it to reflow temperature. Google 'hot air rework' and 'infrared preheater' for some ideas on how it can be done successfully.
Best of luck!!
edit: I see you were successful, and it was because the larger tip transferred more energy to the PCB. Remember that temperature is the enemy, not the total amount of heat energy. Lots of energy gets everything to the temperature you want, and a larger iron indeed can do that. I still think a preheater and/or hot air gun will be the best route for next time, so it's still worth doing a search and see how that approach can work.
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