SDS100: Cold Solder Joint

jonwienke

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The lockup issues I had when recording video with the microscope were due to a flaky micro SD card. A new SanDisk card fixed the issue.
 

kc5igh

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So how much do you think you'd charge to fix cold solder joint problems for us, Jon?

My SDS100 is back from Uniden repair and working well, but it only seems like a matter of time before it may fail again.

-Johnnie (KC5IGH)
 

Canelo56

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I'm thinking $30-40 as an add-on to a GPS installation, or something along those lines.
Is this cold solder a problem withe just the earliest SDS100 or does it see to be with all of them ? The one I have is 2 months old .
 

jonwienke

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Older AFAIK. My unit is serial #541 from the first batch made. But now that I have a solid method for diagnosing the problem, I can start tracking which units have the issue by serial number.
 

kc5igh

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I'm thinking $30-40 as an add-on to a GPS installation, or something along those lines.
That sounds very reasonable, Jon.

If/when my SDS100 has another heart attack, I'll be coming your way. I think I'll pass on the GPS installation and stick with the CSJ fix.

Thanks!

-Johnnie (KC5IGH)
 

darkness975

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I don't usually use the AC at home. It's probably around 82ish degrees in the summer in the room that the SDS100 is in and even warmer in the car on the rare occasions I take it mobile.
 

wtd

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Is this cold solder joint problem just on the SDS100 or does it affect the 200 as well?
 

hiegtx

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Is this cold solder joint problem just on the SDS100 or does it affect the 200 as well?
I don't recall any posts on SDS200's that had to be sent in for repair, where the "fix" noted on the repair confirmation was CSJ. So far, unless I've missed one, the solder joint issue only affects the 100's. I have early production units for my SDS100 & SDS200. So far, no issue with either.
 
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danesgs

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Just in case, I purchased a new accessorie for the SDS100.

View attachment 89068
Nice find on this microscope, price is good also. wold save a lot of eye strain and find things you might miss even with a magnifying glass.
 

wtd

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I don't recall any posts on SDS200's that had to be sent in for repair, where the "fix" noted on the repair confirmation was CSJ. So far, unless I've missed one, the solder joint issue only affects the 100's. I have early production units for my SDS100 & SDS200. So far, no issue with either.
Thank you.
 

jonwienke

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Having studied the issue further, I've figured out some additional details.

First and foremost, the problem isn't actually a "cold" solder joint.The issue is that when the connector was originally soldered to the board, the 40 contact pins weren't touching the board, they were suspended slightly above the board. I don't know if the end pads of the connector were set to a different height, or if there was a misaligned robot arm or fixture involved, but the pins were just barely touching the tops of the solder beads then the connection was soldered. In the image below, you can see a slight gap between the pins and the solder beads on the board on the right side, resulting in a "barely there" connection between the pin and bead that is easily broken.

A simple reflow of the existing solder isn't a reliable fix, because in many cases there isn't enough solder there to fill in the gap between the pin and the board and give the joint a reasonable amount of strength. You have to add enough additional solder to fill the gap.

But in its own way, this is good news. The problem is with the way the J401 connector halvess were positioned immediately prior to soldering, rather than an issue with the temperature of the soldering process or the composition of the solder. That means the issue is confined to the J401 connector, and doesn't appear to apply to anything else. I've seen no evidence of any other components having loose or defective solder joints.


InkedPIC000_LI.jpg
 

ArloG

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Having studied the issue further, I've figured out some additional details.

First and foremost, the problem isn't actually a "cold" solder joint.The issue is that when the connector was originally soldered to the board, the 40 contact pins weren't touching the board, they were suspended slightly above the board. I don't know if the end pads of the connector were set to a different height, or if there was a misaligned robot arm or fixture involved, but the pins were just barely touching the tops of the solder beads then the connection was soldered. In the image below, you can see a slight gap between the pins and the solder beads on the board on the right side, resulting in a "barely there" connection between the pin and bead that is easily broken.

A simple reflow of the existing solder isn't a reliable fix, because in many cases there isn't enough solder there to fill in the gap between the pin and the board and give the joint a reasonable amount of strength. You have to add enough additional solder to fill the gap.

But in its own way, this is good news. The problem is with the way the J401 connector halvess were positioned immediately prior to soldering, rather than an issue with the temperature of the soldering process or the composition of the solder. That means the issue is confined to the J401 connector, and doesn't appear to apply to anything else. I've seen no evidence of any other components having loose or defective solder joints.


View attachment 91078
I just saw that on a Lenovo laptop keyboard ribbon connector the other day.
A chunk of aluminum AC tape for a heat shield on the connector. A light flooding with flux, some wick. A cleaning and more flux. Press the pins against the board and a blob of good old Alpha 60/40 out and away from the pins. All is good. Didn't even get a single bridge.
Robot soldering is cool but did you ever see amateur equipment with SMD that is hand soldered real real good?
Do you think this mfgr. has addressed this QC issue yet? Or do you think ring-chow-ping Shenzhen is actually doing the board population for them?
 

jonwienke

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So far the problem seems to be confined to initial production--units made in 2018. But my sample size is still small.

Also, the SDS100 is built in Vietnam, not China.
 
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