How easily damaged are IC's by heat from soldering?

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eisenhower
 
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How easily damaged are IC's by heat from soldering?

Post by eisenhower »

I stupidly switched the positions ba6110 and la4140, and also stupidly didn't use sockets for them (well, in my defense they are in the BOM and aren't included in the kit).

So now I have to desolder both, which I find to an impossibly frustrating task.
I usually get pissed and just yank ICs out, destroying them, but this time I'm going to use solder braid properly. This means the chips will have get bloody hot.

My question is, will this probably result in the chips getting damaged?

I've been told adding heatsinks help, but this never made much sense, since they also sap heat from the soldering locations..

guest
 
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Re: How easily damaged are IC's by heat from soldering?

Post by guest »

heat shouldnt be too much of a problem
as long as you keep the soldering iron at a reasonable level
and heatsinking the chip can help

get some flux as well as braid
and you wont need to heat it up as much
and use very fine braid
it wicks up the solder better

eisenhower
 
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Re: How easily damaged are IC's by heat from soldering?

Post by eisenhower »

guest wrote:heat shouldnt be too much of a problem
as long as you keep the soldering iron at a reasonable level
and heatsinking the chip can help

get some flux as well as braid
and you wont need to heat it up as much
and use very fine braid
it wicks up the solder better
You see, I've heard before that the soldering iron should be kept at a reasonable level (which I assume means lowish), but that would only increase the time it takes to get the solder and braid heated up, and thus allots more time for heat transfer to the chip itself...

Is it usually possible to completely remove solder with a braid?
I just "desoldered" my ba6110 but it really only decreased the amount of solder on the pins.

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antto
 
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Re: How easily damaged are IC's by heat from soldering?

Post by antto »

i haven't built the x0xb0x i have
and all my soldering experience is.. i built 2 or 3 distortions (most of them failed) and a photo compressor (which kinda worked nice)
so.. my advice is.. train your desoldering skills first, use some old PCB from something you no longer need, desolder a bunch of components to get used to it
in my experience - the desoldering wick can remove all the solder..
when the wick "sticks" a chunk of solder - it cannot stick more than that - don't force it, just move the wick to a clean area and heat it again, it will take more.. repeat till all of the solder is gone

use this information at your own risk :wink: :mrgreen:

guest
 
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Re: How easily damaged are IC's by heat from soldering?

Post by guest »

you should be able to get all the solder out
be sure to use flux
it will help a lot

eisenhower
 
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Re: How easily damaged are IC's by heat from soldering?

Post by eisenhower »

I don't know what it is then, I just can't get it all using solder wick/braid. There is always a little left.
Anyways, I'm going to order a desoldering pump because I'm tired of this wick BANNED.
By now, if the chip could be damaged by heat, its definitely gone.

Thanks

guest
 
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Re: How easily damaged are IC's by heat from soldering?

Post by guest »

did you try with some flux

a pump works pretty well
or if you have some compressed air
you can heat up the solder
and then blow it out
just be wary of hot solder flying around

eisenhower
 
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Re: How easily damaged are IC's by heat from soldering?

Post by eisenhower »

guest wrote:did you try with some flux

a pump works pretty well
or if you have some compressed air
you can heat up the solder
and then blow it out
just be wary of hot solder flying around
I didn't have have any flux. I'll order some of that too.
It could also be my brand of desolder braid (radiohack).
I did try using canned air, but I think it was too cold to be effective.
I also tried torching the pins with a butane torch to no avail.

Really what they need to make, if they don't already, is a solder tip
that can make contact with all pins.

guest
 
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Re: How easily damaged are IC's by heat from soldering?

Post by guest »

they do make tips like that
but probably not for your iron
they are often called hot bar solderers

eisenhower
 
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Re: How easily damaged are IC's by heat from soldering?

Post by eisenhower »

FYI, after a day of trying to desolder the IC's while keeping them intact, I gave up. I HIGHLY doubt anyone can do this successfully given the standard desoldering tools. No one should be told it is possible, since they might ruin other components in the process (which I may have).

I ended up just prying them off and breaking their leads, then desoldering what was left on the pads. It worked.

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altitude
 
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Re: How easily damaged are IC's by heat from soldering?

Post by altitude »

I use some stuff called "chipquik" (http://chipquik.com/) thats designed for SMD parts but also comes in handy for through hole parts since it will keep the solder liquid for a bit longer which is sometimes all you need to get it out.

My general rule is this: If the part costs 2x less than an IC adapter, I dont use one and just cut it out (cut the legs) if it needs replacing. There is no point in hacking up a PCB to rescue a 0.40 $ part

eisenhower
 
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Re: How easily damaged are IC's by heat from soldering?

Post by eisenhower »

Altitude wrote:My general rule is this: If the part costs 2x less than an IC adapter, I dont use one and just cut it out (cut the legs) if it needs replacing. There is no point in hacking up a PCB to rescue a 0.40 $ part
I'd say sockets are always worth it, since if you have to do something like switch parts on the board, you won't need to rebuy the parts (even if they cost less than a dollar, there is still shipping).

That said, I should have thrown in the towel earlier. I was able to get the replacement chips from Willzyx for free, who has crazy good customer support.

To reiterate, desoldering IC's (with more than 3 pins) without physically damaging them is damn near impossible, and shouldn't be attempted ever. The only way to desolder them is to break off the leads.

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cleaninglady
 
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Re: How easily damaged are IC's by heat from soldering?

Post by cleaninglady »

I highly recommend a solder sucker for desoldering.

For example :

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... ink:top:en

I'm sure there are better quality ones available but cheap and cheerful works OK !

The trick i have found is reheating with a bit of extra solder ; if you can't get all of it the first time.

Also , keeping the solder sucker clean by clicking and releasing a few times usually helps.

They take a bit of time to get the technique right but highly recommended.

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mmm
 
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Re: How easily damaged are IC's by heat from soldering?

Post by mmm »

Successfull desoldering of multi-pin components depends on such a lot of different things that it is easy to become frustrated.

I use a desoldering station myself. Those sure ain't cheap; but if you do this on a regular basis it quickly pays off. A desoldering station is basically a soldering iron with a built-in solder sucker (which is run from a pump). Or you could call it a solder sucker with a built-in soldering iron...

It also depends a lot on the type of solder used. Some types of solder have a high flow point; and some seem to stick to the pads and vias more than others. Usually adding more solder first (and reflowing the connection with it) helps here.
It can also be a problem if the holes in the PCB are very small compared to the component wires. There's not much one can do then. Luckily this is seldom the case with IC's.

Anyway, with a bit of practice (and sometimes luck) it is easily possible to desolder most IC's successfully.

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donfuego
 
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Re: How easily damaged are IC's by heat from soldering?

Post by donfuego »

It IS possible. I've desoldered 40 pin ICs with a $10 iron and a sucker. It didn't exactly look like new when I was done, but the part (and the pcb) was still ok. Takes a little training and HEAPS of patience.

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