A few thoughts:
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After HansKarel’s initial comment, I’ve done the tests without any antennas connected. I don’t recall seeing that guidance anywhere in the docs (why not put that note in the QuickTest app next to the start button).
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“The board is cold” is a very subjective requirement. I let it sit till it’s room temperature. Plug it in and get a couple pass results. Within about about 1 minute it starts to fail. If I was in the tropics I wonder if it would work “cold”.
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From an SDR newbie’s perspective, it looks like a bad piece of hardware (because the manufacture’s own test tells me that). What technical argument can you offer to offset my concern.
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So the LimeSDR Mini reports its own temperature. If the QuickTest is temperature dependent, why not set a threshold over which the QuickTest will either not run that part of the test or report it (with a nice technical description of why) as something other than a failure. I confess, I’m a bit hung-up on the idea that a manufactures hardware diagnostic test should consistency pass under all operating conditions. Or at least be smart enough to flag a test that’s out of spec.
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So how about some technical info on why this loopback test is so thermally sensitive? Component placement on board?
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HansKarel offered some experience that puts me at ease but his experience is no guarantee my device will behave the same. Plus, I see a similar instance on the forum where the person was told to RMA it.
(i.e. LimeSDR mini unreliable) -
The comments in this post (New LimeSDR Mini - loopback test failed) seem consistent with what I’m seeing. If I aggressively hold the temperature down by blasting a fan on the bare board, the QuickTest appears to run as many times as you care to run it. However, any minor increase in temperature triggers a failure (and usually on the first of the two loopback tests). Is this an oscillator stability problem? Where do the oscillator(s) live in relationship to the components that generate heat?
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I setup SDRConsole last night and was able to receive broadcast FM with the device. It runs a bit hot but seemed to work for RX. This gives me a bit more comfort that the device isn’t completely dead but still concerned I have a device with Thermal problems.
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I won’t have time to try the TX functionality before the 90-day return window expires. This was a big ticket item for me, part of my angst is frustration that I waited so long before giving this a try and now I’m concerned if the TX functionality has issues I’ll get the “sorry too late” response when I try to resolve the problem.