6 posts in this topic

I've got a number of old boards that are of no use or do not work that have some precious logic chips on them I'd like to use!

Unfortunately, not sure if it's due to age of chips, heat taken by chips or just plain cheap-skate manufacturing that makes them near impossible to desolder using the 'blob solder' method, tried on 4 of them in various blob ways and they've all cracked or split or came apart entirely rendering the chip useless. These are all on double sided PCBs which makes them even more of a pain to remove.

So I'm asking for suggestions on how to remove them but keep them in working order (assuming they are in working order), I've got a soldering iron, desolder braid and a solder pump but don't think that'll work. I was looking at hot air reflow stations but they seem more for SMD components and even if they're not, ?50 being the cheapest on ebay from china, not going to risk buying it and it being useless. I was also thinking about a similiar method to how components are soldered in china using 'liquid solder baths' but don't really have a clue oh how I'd do it, or if it'd even work!

So yeah, any ideas?

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Make sure you use flux to get the old solder to flow. also if the pins are in a ground plane they will be harder to heat up so you may want to pre-warm the board. a heat gun/hair drier would work. and last, try some ChipQuik! It is a low temp alloy that stays molten much longer than solder so you can blob the entire chip and it stays liquid the entire time.

http://www.amazon.com/ChipQuik-Removal-Includes-Flux-Alloy/dp/B001KAC3IG/ref=sr_1_fed0_2?ie=UTF8&qid=1354837622&sr=8-2&keywords=chip+quick

dm.

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The quikchip idea sounds good - $10 on amazon.com but it's ?15 on amazon.co.uk... Again quite pricey to remove some logic chips.

I'll give a hair dryer a go though I did break up some of the PCB to be very small and it still wasn't coming off (temperate controlled soldering iron was set to the beginning of the 'red' temperature zone). I'll try some flux as well and see if that helps! Thanks

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Had much more success and I've found the problem/culprit! Phillips ICs, they're ****.

The majority of logic chips on this big board are phillips, every single one has cracked, broken or came apart.

Desoldered some TI, ST and NS ICs all without problems.

So there you have it, electronic engineers - avoid phillips ICs at all costs.

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Heat-gun with the low profile metal funnel and a "solder sucker" has worked for me on games consoles.

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You can lay down a piece of wire, tack solder it to the two pins on each end, then use the solder blob method. (FLUX! FLUX! FLUX!). The wire will help the solder blob.

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