As I've mentioned elsewhere, I sent my SDS100 in for the cold solder joint issue, and after about a month away from home, it came back working again. Until today. The A/C in my house is broken, and ambient has been 85F or so the last couple days, and so the SDS100 has been running warmer than usual as a result.
The symptoms were nearly identical to before, except instead of getting no RSSI reading while a transmission, I was sometimes getting -40dBm, which is unusually strong. Everything else was the same; super slow scanning, pulsing static on multiple channels, etc. Not relishing the thought of spending another month without the scanner, I opened it up to see what Uniden had done, in the hope that it might yield a clue to the problem. And I found something I'd missed previously:
The third pin from the right seems to be the culprit. The solder connections on either side have touched up by hand, but the third one hasn't, and if you compare it to the machine soldered pins on the left, it has conspicuously less solder than all the others. After reworking that joint so it matches the others, the radio works properly again. Missing that dry joint is clearly a fail on Uniden's part.
The other thing I did was shimmed the SMA connector on rear circuit board so it isn't putting lateral stress on the connector. With the front circuit board screwed down lightly, there was a ~0.2mm gap between the inner SMA connector retainer and the case, and when tightening the outer SMA retainer, the rear board was pulled upward relative to the front board, which pulled sideways on the J401 connector.
To solve the problem, I 3D printed a spacer that was 0.2mm thicker than the inner retainer, and installed it so that after tightening down the outer SMA retainer, the two halves of J401 are correctly aligned, and there is no lateral force on it.
The symptoms were nearly identical to before, except instead of getting no RSSI reading while a transmission, I was sometimes getting -40dBm, which is unusually strong. Everything else was the same; super slow scanning, pulsing static on multiple channels, etc. Not relishing the thought of spending another month without the scanner, I opened it up to see what Uniden had done, in the hope that it might yield a clue to the problem. And I found something I'd missed previously:
The other thing I did was shimmed the SMA connector on rear circuit board so it isn't putting lateral stress on the connector. With the front circuit board screwed down lightly, there was a ~0.2mm gap between the inner SMA connector retainer and the case, and when tightening the outer SMA retainer, the rear board was pulled upward relative to the front board, which pulled sideways on the J401 connector.
To solve the problem, I 3D printed a spacer that was 0.2mm thicker than the inner retainer, and installed it so that after tightening down the outer SMA retainer, the two halves of J401 are correctly aligned, and there is no lateral force on it.
