SDS100: Cold Solder Joint

jonwienke

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This video is from a customer's SDS100 that had been sent to Uniden about a year ago for the cold solder joint problem. Of the 20 joints on one side of the connector, Uniden had repaired 4, but every one of the remaining 16 were bad. They were still connecting (the radio worked when I received it), but obviously a problem waiting to happen.


The same set of joints after I resoldered them:
 
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jonwienke

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One thing I'd like to point out: even though all of the non-repaired joints in the video were defective, they didn't LOOK defective, even under magnification, and they still connected electrically. The radio functioned correctly when I received it. It wasn't until I probed the joints with a fine-tip dental pick that they were shown to be bad.

So I can understand why Uniden didn't catch the problem when they had the radio, but I can also understand why some people have having recurring issues involving the radio going to Uniden multiple times. I wasn't able to figure the problem out myself, until I got the microscope so I could see what i was doing, and thought of the dental pick test.
 

jonwienke

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So far, yes. And in 80-90F heat in the house, since the air conditioning died.
 

jonwienke

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Hah.. Ants in the condenser unit contactor?
Nope. A refrigerant leak deep inside the evaporator coil where it's nearly impossible to repair. Waiting on a replacement coil.
 

mancow

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Great find Jon!

Now I know this so called CSJ can probably be fixed by those with the correct soldering tools, eyesight (and any needed external magnification aids!) plus steady hands. Even with my aging eyes, I could do as good or better of a job than I see in your picture.
I've always wondered if anyone with the CSJ issues attempted to inspect J401 and its mating connector. Now I know!

I'll need to look at the SMA spacing you found after tightening the board in mine next time I open it. That could very well be a manufacturing allowed tolerance but I agree and it should not exist. Especially if it puts stress on the J401 connector.

Thanks for posting the nice and clear pics along with your findings. That poor looking 3rd pin stuck out like a sore thumb before I even read your text.
I'd liked to have seen this radio's J401 before Uniden serviced it. That may have been interesting.

Yep, thanks. Now we can fix it ourselves, potentially.
 

jonwienke

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Yep, thanks. Now we can fix it ourselves, potentially.
Magnification is mandatory. The pins are spaced about 0.5mm center-to-center. Laying out the solder paste and so on just after a cup of coffee is not a good idea.
 

mancow

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One thing to look out for are the delay it has from you move the solder tip under the lens and when it is presented on the display. Too much delay and you are bound to make mistakes when you solder and you will curse that cheap $50 microscope.

/Ubbe

I've had one for about a year. There isn't really any delay that I can perceive. It's a very very handy tool to have on hand. I use it quite a bit.
 

jonwienke

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It has a 50/60Hz selectable refresh rate, so the screen lag is minimal.
 
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