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-   -   A successful damaged SMD inductor repair (https://www.vintage-radio.net/forum/showthread.php?t=178587)

Jolly 7 5th Apr 2021 9:40 pm

A successful damaged SMD inductor repair
 
3 Attachment(s)
I don't normally work with SMD components as they are so tiny and difficult to assemble. However, I recently repaired an active antenna that was damaged in the post. An SMD inductor core was broken. I managed to negotiate a partial refund, but rather than send the item all the way back to China, I attempted the repair myself. I am not sure how they do this in the factory, but unlike the other components, the solder terminals were hidden under the inductor. I flooded it with solder from the side trying to get it to make contact with the solder pads and this did the trick. I did not have any SMD inductors, but was successfully able to solder a full size inductor as a replacement.
The antenna is BF998 based and works quite well after the repair. The main unit is small enough to fit into a Smarties tube, to the bottom of which I have fitted a PL259 connector.

Radio1950 6th Apr 2021 5:10 am

Re: A successful damaged SMD inductor repair
 
Well done.

I have used small "through hole" inductors to replace SMD types.
Bend one leg back and mount vertically onto the solder pads like you have.

Jolly 7 6th Apr 2021 3:20 pm

Re: A successful damaged SMD inductor repair
 
Thank you.
Given the minute size of SMD inductors, I wonder if exposure to hot air during the assembly process could adversely affect the electromagnetic properties of the ferrite cores ? It would seem that the whole component rather than just the leads are being exposed to very hot air.

Pamphonica 6th Apr 2021 6:20 pm

Re: A successful damaged SMD inductor repair
 
Well done, and very satisfying I am sure!
I think that the SMD soldering process uses carefully controlled "ramping" of the temperature up and down so the components should not suffer during the process, and there should be no temperature differentials to cause bad joints. But any failure in this ramping would certainly stress a crystalline object like a ferrite.

Al (astral highway) 6th Apr 2021 9:43 pm

Re: A successful damaged SMD inductor repair
 
Kudos to you! Very neat result.

That must be satisfying! I've been honing my SMD skills over the last two years so I don't get left behind!

Jolly 7 6th Apr 2021 11:11 pm

Re: A successful damaged SMD inductor repair
 
Thanks everyone for the kind comments. I hope to post some pictures of the assembled antenna, power unit etc. under Homebrew Equipment in the next couple of days.


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