Re: Replacing SMD component


JE Jesson
 

In a pinch, a toothpick with a bit of clay helps position the surface mounted part into position and soldering one leg to anchor the part.  Solder the other leg and make sure both sides are glossy. 

Joe W2JEJ

On Tue, Sep 8, 2020 at 10:27 AM R. Tyson via groups.io <tysons2=btinternet.com@groups.io> wrote:
Hi,

Due to a senior moment ( I am old enough to be entitled to have them) I need to replace Q90 which is a dreaded SMD device. Ten SMD 2N3904 transistors arrived with the mail today. Wow, they are so small. I had previously found the location of Q90 on the board and verified it was no longer functioning and noted it's position, which is not too bad to get at. I am now waiting for a 1mm tip for my soldering iron and more importantly some liquid flux.

Meanwhile I had a look at YouTube and found some ideas for replacing SMD components without special tools. I opted for the following idea, photos below.

I cut down an old, knackered soldering bit and cleaned it up as shown in the photo. I then applied some heat conducting paste (probably not essential but I already had some). I then wound 1mm copper wire onto the remains of the soldering iron tip. The two prongs that are formed should enable me to heat all 3 connections on the transistor at the same time and it (should) come off the board easily. Well.... it looks easy when the guys do it on YouTube !

Reg                   G4NFR

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