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Tantalum recap success

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Well I don't care what you all say, but recapping with tantalum capacitors is HARD! Last time I tried, I gave up and switched to electrolytics - which I found much easier.

 

That said, this time I had success...

 

IMG_20190416_215115.thumb.jpg.abafcb3323598547316f2d8ea2e26416.jpg

 

I bought this NOS motherboard over a year ago, still in original packaging. Apart from the leaky caps, the board is immaculate.

 

Yes my caps may be a bit wonky... but hey the board now works like a charm so I'm happy :)

 

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Those are quite big... if you choose a smaller size soldering will be easier as the cap itself won't cover the whole pad.

Edited by Bolle

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30 minutes ago, Bolle said:

Those are quite big...

There's different sizes?!?! Lol that would have made it so much easier! :)

 

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For other readers, here's how I stick tantalum caps down:

  1. Wick solder off both pads
  2. Generously tin one of the pads
  3. Apply heat to the tinned pad
  4. Slide cap into place with tweezers
  5. Remove heat from pad, then let go of the part with your tweezers (at this point, your cap will stay put because it's soldered down)
  6. Heat and solder the other pad

I found the experience to be super frustrating until I figured this out! Now, and Classic II or SE/30 recap doesn't scare me at all, except for the removal of the old caps. I have not really figured out that part yet.

Edited by PotatoFi

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8 minutes ago, PotatoFi said:

I found the experience to be super frustrating until I figured this out! Now, and Classic II or SE/30 recap doesn't scare me at all, except for the removal of the old caps. I have not really figured out that part yet.

 

That is the method I've been recommending for soldering on new.  

 

For removing old, I still prefer the two soldering iron method.  I used to recommend a pair of 15W soldering irons, but those are too low powered for bigger bypass caps.  They're good for changing SM resistors (e.g. clock chipping operations), but not so good for recapping.   Now, if you don't have temperature controlled irons, I think a pair of 45 watt pencils works well for cap removal.    Anything from 35 - 45 would probably be fine.  I just chose wattages based on what Radio Shack commonly sold -- not so relevant any more.

 

Anyway, a pair of $10 - $15 45W pencils is a lo cheaper than buying two temperature controlled stations....

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Just now, trag said:

For removing old, I still prefer the two soldering iron method.

How do you hold two irons and lift away the old capacitor at the same time? It's probably super obvious... but I'm just not seeing how.

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I am a twister... it’s not the right way to do by the book but works 100% and is safe if done correctly. Key is pushing down on the cap while gently twisting it left and right until the legs snap off.

It’s a matter of seconds to get all caps off a board once you get a feel for it.

 

Fun fact: I told my better half how to do it and she got all caps off an SE/30 board with zero pads lifted on the first try... so this is basically fool-proof to do :evil:

Edited by Bolle

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I’ve found flush cutters to cut the cap off then flux + desoldering gun to work really well for removing caps and not damage pads. Makes for nice shiny clean pads as well.

 

https://i.imgur.com/QpQEJ5C.jpg[/img]

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There are many workable methods.

2 hours ago, PotatoFi said:

How do you hold two irons and lift away the old capacitor at the same time? It's probably super obvious... but I'm just not seeing how.

 

Once the cap is loose, just lift it between the two pencil tips.   The solder tends to make it stick to one tip or another anyway.  It's good to keep a moist sponge handy to wipe the old cap onto.

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I always pre-tin the pads and separately the caps. Then I use a tiny dab of adhesive to place the cap. I don't wait fo the adhesive to cure per say, generally something like silicone provides enough "stiction" to keep it from moving. The amount is tiny (head of pine dot) and if you have recapped before, you have seen even the factory uses something. I've seem it in red or blue usually. Although I am not sure why they use it. Anyway, after so many re-caps this method has proven really solid. You can even let the adhesive set if you really want trouble-free soldering.

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3 hours ago, Bolle said:

I am a twister... it’s not the right way to do by the book but works 100% and is safe if done correctly. Key is pushing down on the cap while gently twisting it left and right until the legs snap off.

It’s a matter of seconds to get all caps off a board once you get a feel for it.

 

Fun fact: I told my better half how to do it and she got all caps off an SE/30 board with zero pads lifted on the first try... so this is basically fool-proof to do :evil:

I can vouch for the twist method too- I've done 2 boards this way with 100% success.

 

1 hour ago, unity said:

Then I use a tiny dab of adhesive to place the cap.

This is a great idea, because holding the cap in place while you solder is tricky. I'll definitely try this with my next board thanks.

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21 minutes ago, ants said:

I can vouch for the twist method too- I've done 2 boards this way with 100% success.

On one hand, YOU GUYS ARE FREAKING ME OUT. On the other, I lifted one pad while desoldering from an SE/30 board for a friend, so I don't have much room to argue here. :)

 

@ants, nice work. Thanks for preserving another SE/30 logic board! I feel like those are a precious commodity, and every one that gets the PRAM battery replaced and new tantalum caps soldered in is just one more that will stay in the pool of surviving boards.

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1 hour ago, PotatoFi said:

YOU GUYS ARE FREAKING ME OUT

Haha I freaked out when I first read about it - but once you try it you'll see that it's really not that bad :D

 

Thanks for the kind words.

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@ants - the other reason I do the adhesive is then I can make sure the caps are nice and square. I hate crooked caps on my "museum" machines. Makes for a very pro look.

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1 hour ago, unity said:

@ants - the other reason I do the adhesive is then I can make sure the caps are nice and square. I hate crooked caps on my "museum" machines. Makes for a very pro look.

I agree! I'd consider fixing mine up, but there's a very good chance I'd wreck a solder pad.

 

I actually have one more SE/30 motherboard lying around, I'll go for perfection on that one with smaller caps as per @Bolle's suggestion and your adhesive idea.

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Jealous of your SE/30's... my dream Mac right there. I have recapped an SE/30 board for a friend (success) so I'm at least familiar with the logic board. :)

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