Asteroids DAC chip removal

Reddogg

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Hey guys, I'm trying to replace an AD561J on an Asteroids board, but can't get the old one off. I will socket the new one.

I've tried cutting the legs so I can pull then thru while de-soldering, but the legs are too small to cut without scratching the board. At least with my wire cutters. I also tried adding new solder to the old to help it flow, but till can't get it all out.

I've got most of the solder gone, but the chip still won't budge. No pads are lifted, yet, but I'm running out of ideas, and really don't want to screw this up.

Anyone got another or better idea? I'm no expert by any means.

Thanks.
 
Get some good little cutters (like the Xcelite 170), or very carefully use a Dremmel cutter.

Are you using a desoldering station, or a soldapult solder sucker, or wick?

Sometimes, I need to add some new solder to the joint before getting a good desolder.

Be very careful and very patient. It's much easier to snip off the old IC and use the "pliers-on-one-side-soldering-iron-on-the-other" technique than to get all umpteen legs to desolder cleanly to pull the old IC off intact.
 
Good thing I hit refresh before reply... I was just about to say the same thing as Darren.
A decent pair of diagonal cutters is only going to cost you a few bucks. Dremel works too, but can make a mess.
 
Great!

Thanks for the quick responses guys!

I've been using a wick, and a sucker, but the sucker...sucks!

I'm headed to R-vac to see what I can find.
 
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i use a dremel on the legs where they enter the ic chip.

then using tweezer and a 700*F fine tip soldering iron, i pull each leg off the board.

then follow up with a desoldering station (or wic if no desoldering station is available)

if no wick, i use a #60-#70 carbide drill bit and just hardrill the solder holes.

requires very delicate hands.
 
I found that a so-called solder hot air reworking station works great for removing chips with minimal fuss, mess, and significantly reduces the chances of lifting traces. It uses a hot air nozzle to melt the solder around all of the chip legs simultaneously and then the chip just lifts off easily while the solder is still liquefied.

I've used it replace many chips on such boards as Star Wars, Williams CPU, Tempest, etc. You just have to be careful so as not to burn the board itself...be sure to watch a video on how to use the thing if you get one as it's pretty easy, but a visualization is the best way to learn. Here's a good one: http://www.youtube.com/watch?v=MOEHstgaVLM&feature=related.

I got mine online, but I just saw them for sale at my local Fry's for a pretty reasonable $100.

Jon
 
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