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Old 10-27-2012, 06:41 AM   #1
electrobe
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Default How do you properly remove a surface mounted voltage regulator

I want to know the proper way to remove a smd voltage regulator like the one in the photo without burning it up? The chip is soldered in three locations (the two pins & the back). Please be specific like tip size, solder type etc. I am not sure if this is the proper forum so please don't be angry with me. I posted in general electronics section but I have not received a reply as of yet. I thank you for any help provided.
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Old 10-27-2012, 06:53 AM   #2
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Default Re: How do you properly remove a surface mounted voltage regulator

Hot air rework, or a $20 heat gun from harbor freight.
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Old 10-27-2012, 08:53 AM   #3
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Default Re: How do you properly remove a surface mounted voltage regulator

OR
'
Put the solder iron tip on the tab, right about where the join between the tab and the pcb is.
Wait a few seconds for the chip and pcb to heat up and then add 60/40 solder to the join point between the tab of the chip and the pcb. Basically put a big blob of solder there. Move the iron tip back and forth on the tab to warm up the whole width of the tab equally. Don't press too hard on the iron top because you might break the pcb traces and pads.

Add a bit of solder to the legs of the chip as well.

Now move your iron between the legs and the tab several times, the 60/40 solder remains for a few seconds in a liquid state so you should be able to get all three points liquid.
When you think this happens, you can just push a bit on the sides of the chip with something (a match, a screwdriver tip, not your finger because the chip is very hot by this time) and the chip should move away from the board.

You're sort of doing the steps here in the opposite way: http://www.youtube.com/watch?feature...fAlfQE#t=1850s
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Old 10-27-2012, 09:37 AM   #4
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Default Re: How do you properly remove a surface mounted voltage regulator

I removed a voltage regulator by desoldering and lifting the two pins, then heating the tab while adding solder. The regulator was extremely hot after it finally came off, but it still works. I did this with a 25W soldering iron.
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Old 10-28-2012, 04:54 PM   #5
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Default Re: How do you properly remove a surface mounted voltage regulator

Thanks guys for the help it worked perfectly.
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Old 10-29-2012, 09:54 AM   #6
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Default Re: How do you properly remove a surface mounted voltage regulator

Quote:
Originally Posted by Evil Lurker View Post
Hot air rework, or a $20 heat gun from harbor freight.
Look for sales I got mine for 10 bux!
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Old 10-29-2012, 12:10 PM   #7
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Default Re: How do you properly remove a surface mounted voltage regulator

Quote:
Originally Posted by lti View Post
I removed a voltage regulator by desoldering and lifting the two pins, then heating the tab while adding solder.
Ding!! We have a winner! Since the legs are easy, lift 'em first. Kind of a waste to get the tab heated enough only to be stopped by the legs.
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Old 10-29-2012, 01:07 PM   #8
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Default Re: How do you properly remove a surface mounted voltage regulator

Quote:
Originally Posted by lti View Post
I removed a voltage regulator by desoldering and lifting the two pins, then heating the tab while adding solder. The regulator was extremely hot after it finally came off, but it still works. I did this with a 25W soldering iron.
This is not generaly good, for me the plastic corner usually break when I try to lift the legs.
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Old 10-29-2012, 01:10 PM   #9
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Default Re: How do you properly remove a surface mounted voltage regulator

I used to do it as Marius said, until I have got a hot air station, or just cut the two legs and then do the blob on the tab.
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Old 11-07-2012, 06:09 PM   #10
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Default Re: How do you properly remove a surface mounted voltage regulator

I have yet to remove an SMD but there is such a thing as an SMD removal kit by Jameco, pt. no. 141305 It's about $16 but may facilitate component removal.
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Old 11-07-2012, 07:08 PM   #11
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Default Re: How do you properly remove a surface mounted voltage regulator

Well, if you want to spend money, you might as well get ChipQuick, which is a special solder that stays liquid for close to (if not more than) a minute.
It makes desoldering really easy.

But really, with a good solder iron, it's really easy to desolder.

In reply to smason, sometimes it's not a good idea to go on the legs first. There's usually a bit ground pad and the legs are just on thin traces - the ground pad might pull a lot of heat away, so by the time you actually get the lead free solder liquid to get the legs up, you might pull the thin traces up as well.

Heating up the tab also heats the board so when you actually add a bit of solder to the legs, the legs are already hot, it's very easy to add a tiny bit of solder and after a bit of re-warming of the tab, the chip will just slide away.
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Old 11-07-2012, 07:38 PM   #12
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Default Re: How do you properly remove a surface mounted voltage regulator

Desoldering is piece of cake if you have powerfull enough lamp or other tool. But soldering in replacement, that's different story if you want the tab to be soldered properly to a board
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Old 11-10-2012, 01:54 PM   #13
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Default Re: How do you properly remove a surface mounted voltage regulator

Hot air on the small legs, a standard solder iron on the tab. With practice you know how much heat part needs to minimize heat damage. If the board is vertical then the part will just fall off.

Other ways work but will destroy the transistor, the board, or both.
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Old 11-10-2012, 02:07 PM   #14
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Default Re: How do you properly remove a surface mounted voltage regulator

Quote:
Originally Posted by Behemot View Post
This is not generaly good, for me the plastic corner usually break when I try to lift the legs.
The voltage regulator was in a DPAK package (nearly identical to the TO-252 package shown in the picture). It came off with no damage to the board or the regulator.
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Old 11-11-2012, 07:21 PM   #15
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Default Re: How do you properly remove a surface mounted voltage regulator

Quote:
Originally Posted by Behemot View Post
This is not generaly good, for me the plastic corner usually break when I try to lift the legs.
Same here. I did manage to remove a few with lti's method without breaking them - these were the first that I attempted, though. The ones following that I kept breaking. Beginner's luck I suppose.

Since then, I have experimented with many other methods. Hot air works fine but is too slow IMO. So my favorite method (and the one I have most success with) is with 2 powerful irons (50W to 60W minimum, preferably with chisel tips and temperature regulated). When removing a standard DPAK MOSFET, for example, I first add lots of solder to the tab of the MOSFET. Next, I add lots of solder across the legs, usually enough to bridge at least 2 of them. Finally, I heat the tab with one iron and heat the blob of solder over the legs with the other iron. In just 3 seconds, all I have to do is just push the MOSFET away from its spot and the job is done. No preheating required and no possibility of damage to the nearby components like you have with hot air. Also, after I'm done using this method, I re-collect the solder left on the board and the MOSFET with the soldering iron and then collect it in a container for reuse again with this method.
Also, the above method is not limited to DPAK MOSFETs. I've used it for removing SOP ICs as well (up to 20 pin). Just put 2 blobs of solder across the IC's leads on each side and heat with the irons.
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Old 11-11-2012, 07:29 PM   #16
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Default Re: How do you properly remove a surface mounted voltage regulator

I now have 125W pistol iron, so I heat up tab with some solder, than either lift it whole up , desoldering just legs than, or go around heating tab, first leg, second leg and tab again. After few tries, it can be removed.

In the worst case scenario I get my 60W monster pen iron and when it heats finally, I can burn through a wall with that Once kept it running and the pike, massive piece of cupro-alloy ~8 cm in length and 1 cm in diameter, being stabbed into something massive and metal, just bend down under all the heat and weight

But the hot air gun is good if you are desoldering lots of stuff from dead PCB, including FETs. Once it's all heated, you just pick everything up with your pliers, one after other
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Old 11-17-2012, 04:10 PM   #17
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Default Re: How do you properly remove a surface mounted voltage regulator

Hot air alone would be very slow to remove a DPAK. The entire board would be practically on fire before anything would move. That's why I put the solder iron on the tab which not only dumps lots of heat under the transistor, the solder iron can help kick the part off the board. The first transistor takes about 45 seconds to remove. Once the area is warm transistors take about 8 seconds to remove.
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Old 11-17-2012, 05:05 PM   #18
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Default Re: How do you properly remove a surface mounted voltage regulator

^ +1
Hot air is even worse if you have electrolytic caps or other small SMD parts around.
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Old 11-17-2012, 06:30 PM   #19
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Default Re: How do you properly remove a surface mounted voltage regulator

Quote:
Originally Posted by lti View Post
The voltage regulator was in a DPAK package (nearly identical to the TO-252 package shown in the picture).
They are the same thing. Why does that package have two different names, and why do component datasheets list only one of those names like they are incompatible packages?

On the board I removed that part from (the main board from a dead CD-ROM drive), it was easy to remove with a 25W soldering iron.
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Old 11-17-2012, 07:53 PM   #20
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Default Re: How do you properly remove a surface mounted voltage regulator

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Originally Posted by severach View Post
Hot air alone would be very slow to remove a DPAK. The entire board would be practically on fire before anything would move. That's why I put the solder iron on the tab which not only dumps lots of heat under the transistor, the solder iron can help kick the part off the board. The first transistor takes about 45 seconds to remove. Once the area is warm transistors take about 8 seconds to remove.
Aluminium foil helps with heating only the very area you want to heat and dumping heat from other parts away.
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