"But wait… How do I know all that? That’s because Radxa did the right thing and publicly announced the issue on its forum, apologized to its users, and offered resolutions we’ll discuss below."
That's because they're selling to a market where knowledgeable people talk to each other. If they hadn't done that, they would have been faced with "Radxa products unreliable, not recommended". Since what they're selling is basically a me-too product, that could have killed them.
A QC test should at least test every component on the board - including passive resistors. That lets it test for bad solder joints, DOA components, etc.
Clearly their test could pass if a bunch of components were missing. That's their main mistake.
How do these tests work? I can imagine a test where you connect up all the peripherals flash test firmware and observe the results, but presumably that doesn’t test parts of the board that aren’t between io pins and the processor. How do they test every single component on a board that costs ~$40? Presumably it’s not cost effective to do this manually. Do they robotically place sensor probes into the circuit around every component?
It isn't unusual for a big circuit board to have 1000+ test points on it. A big machine will connect to all the test points and measure all the impedances at high frequency - this allows you to easily detect signal reflections from a short or open circuit somewhere it shouldn't be, and also detect if a chip has a loose pin.
The machines are expensive, but the whole test can be done inside 1 second or so, which makes the process pretty cheap.
Famously, those same test points are what made installing modchips in early xboxes and playstations so easy - you just have pins touch a few of the same test points that were used for the factory test to override some signals to get your code running during bootup.
You have machine vision inspection systems. There are bed of nails systems that can measure impedance of nodes on the board and run functional tests. Really high reliably stuff gets x-rayed.
If you're doing true mass production you perform inspections/tests at each step of the process.
> Those are not pin-to-pin compatible chips, and two circuitry were made for the board requiring two BoMs as it’s not just possible to only replace IP2315 by CH224D [WITHOUT BUILDING THE WHOLE BOARD TO THE APPROPRIATE BOM].
Either chip would have worked if built to the correct BOM. But instead they used a BOM for one chip and placed the other chip, causing complete non-functioning for anything over 5V.
Yea. Be clear about your build and assembly process.
I don't think this takes away from the article's point: The shortage is forcing unusual design decisions that introduce classes of error that wouldn't occur with normal design processes.
Which is fine; it just didn’t make sense as written. It looked to me like the mfg made layouts for two chips, but the blog writer implied one chip would not work as in would never work. Obviously it does, and the problem was actually missing discrete components elsewhere.
The title is misleading, and the blog conclusion is too:
"While there have been some mistakes along the way and lessons learned, this particular mass production mishap would not have happened without the current supply shortage that increased the complexity of the design, sourcing, and manufacturing."
This were internal communication errors on multiple counts, and those shortfalls had nothing to do with supply shortages. Internal communication didn't ensure QA knew what to test, and that a part manager knew what to order/source.
It doesn't matter why the board was designed the way it was, many boards are way more complex than the board in question! Many boards also have multiple revisions, and changes, through their lives.
Board complexity did not cause the issue here, communication issues did.
"But wait… How do I know all that? That’s because Radxa did the right thing and publicly announced the issue on its forum, apologized to its users, and offered resolutions we’ll discuss below."
That's because they're selling to a market where knowledgeable people talk to each other. If they hadn't done that, they would have been faced with "Radxa products unreliable, not recommended". Since what they're selling is basically a me-too product, that could have killed them.
The QC test was bad...
A QC test should at least test every component on the board - including passive resistors. That lets it test for bad solder joints, DOA components, etc.
Clearly their test could pass if a bunch of components were missing. That's their main mistake.
How do these tests work? I can imagine a test where you connect up all the peripherals flash test firmware and observe the results, but presumably that doesn’t test parts of the board that aren’t between io pins and the processor. How do they test every single component on a board that costs ~$40? Presumably it’s not cost effective to do this manually. Do they robotically place sensor probes into the circuit around every component?
It isn't unusual for a big circuit board to have 1000+ test points on it. A big machine will connect to all the test points and measure all the impedances at high frequency - this allows you to easily detect signal reflections from a short or open circuit somewhere it shouldn't be, and also detect if a chip has a loose pin.
The machines are expensive, but the whole test can be done inside 1 second or so, which makes the process pretty cheap.
Famously, those same test points are what made installing modchips in early xboxes and playstations so easy - you just have pins touch a few of the same test points that were used for the factory test to override some signals to get your code running during bootup.
There is a bunch of technology for this stuff.
You have machine vision inspection systems. There are bed of nails systems that can measure impedance of nodes on the board and run functional tests. Really high reliably stuff gets x-rayed.
If you're doing true mass production you perform inspections/tests at each step of the process.
The article is missing some clarifying words.
> Those are not pin-to-pin compatible chips, and two circuitry were made for the board requiring two BoMs as it’s not just possible to only replace IP2315 by CH224D [WITHOUT BUILDING THE WHOLE BOARD TO THE APPROPRIATE BOM].
Either chip would have worked if built to the correct BOM. But instead they used a BOM for one chip and placed the other chip, causing complete non-functioning for anything over 5V.
Yea. Be clear about your build and assembly process.
I don't think this takes away from the article's point: The shortage is forcing unusual design decisions that introduce classes of error that wouldn't occur with normal design processes.
Which is fine; it just didn’t make sense as written. It looked to me like the mfg made layouts for two chips, but the blog writer implied one chip would not work as in would never work. Obviously it does, and the problem was actually missing discrete components elsewhere.
It's all in there already, "requiring two boms" "not just possible to ONLY replace IP2315 by CH224D"
The title is misleading, and the blog conclusion is too:
"While there have been some mistakes along the way and lessons learned, this particular mass production mishap would not have happened without the current supply shortage that increased the complexity of the design, sourcing, and manufacturing."
This were internal communication errors on multiple counts, and those shortfalls had nothing to do with supply shortages. Internal communication didn't ensure QA knew what to test, and that a part manager knew what to order/source.
It doesn't matter why the board was designed the way it was, many boards are way more complex than the board in question! Many boards also have multiple revisions, and changes, through their lives.
Board complexity did not cause the issue here, communication issues did.
You’re right but anyway the consequence of the supply shortage is a “mess”, more than a “mass mishaps”.
This just makes me more likely to buy their product.
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