Re: looking for technics to replacing the IC4 FST3253


Mont Pierce KM6WT
 

David,

A Hot Air SMD "Rework" gun is the way to go.  And, can be a lot of fun.
Don't be afraid to give it a try, you might find it as much fun as I do.  :)


On Mon, Nov 9, 2020 at 03:20 AM, Mike Berg wrote:
Hot air rework station @$125 is the best investment for removing sm ICs.
Amazon has several in the price range of $30-$50 (click here). 
The Kohree 858D for example is about $36 on Amazon.
The inexpensive ones, although not being the best on the market, should be adequate for the job.


Use the small nozzle, and only need to heat the one part.  Once solder is melted it will come right up, easy.
If you have some junk boards around with SMD parts, have a go at them for practice.


Also, soldering new part is very easy with the heat gun.

Clean the pads with solder wick.

Then, using solder paste in a syringe (also available on Amazon) put a bead of solder paste "ACROSS" the pins 1 thru 8, and another bead ACROSS pins 9-16.  Just like your crossing a series of ts  like this    tttttttt

Here's a YouTube example, starting at 3:44 thru 4:08   https://www.youtube.com/watch?v=RODp8HSlFPA
except he uses A LOT MORE solder paste than is really necessary...     
(this is NOT the best example, but just one I found quickly...)

VERY LITTLE solder paste is needed.  It only takes a paper thin amount of solder between the leads and the pads.


The FUN PART is watching the solder paste as it melts.   The Solder Mask, and Surface Tension of the melted solder will pull the solder on to the pads, and away from the solder mask.  Surprisingly, there will be NO Bridges most of the time, unless you put down way too much solder paste.


I really have a lot of fun building SMT kits, or kits with some/most SMD parts. 


73
km6wt

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