Ba,
I saw your update and it looks like there are only a few pins for test points. Are you testing entire board or just the software load portion.
Martha Montgomery
The test jig looked neat, like too neat… Panels, curved corners and Ring light button 
When you mentioned test jig, I was expecting an unholy barely working mess, similar to AI’s expectations…
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The main issue we’re focusing on is this faulty soldering on one of the chips, that Bar talked about. The rig is also very handy for flashing firmware.
But also, the onboard firmware itself has a built-in self-test function that runs every time it’s powered on and lets you know, if there are any problems with the hardware.
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OK then I was correct. Flashes software and passes self test, does not equal 190 percent tested. I have had to troubleshoot lots of repairs that that passed those condition and still would not work on aircraft.
Martha Montgomery
A few questions you might ask the factory that manufactured the boards:
- Were the boards inspected 100% using AOI (automated optical inspection), and
- Were the boards inspected 100% using ICT (in-circuit-test, also referred to as a bed of nails tester)?
ICT relies on a large number of test points being designed into the layout. Depending how much room you have for test points and how many layers you have, you often can’t test every node, but you can usually get most of them.
Happy to talk about QC testing in detail if you’re interested.
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I know in circuit testing. Used to run tester at Boeing. With several thousand test push pins in a 2ft square multilayer test board held down with vacuum power. Four 7 fy equipment racks filled with different kinds of test equipment. Millions of dollars worth. I know in circuit testing. But what Bar is doing appears to just making sure software loads to board. Then that the selftest function works. What I am saying that faults occur that are nor caught by self test.
Martha
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Boeing was probably doing some very sophisticated testing, involving injection of signals and analysis of RF waveforms and the like, and you are right, these are very expensive setups.
I’ve spent the last 20 years building consumer products at Asian factories, and the commonly used ICT uses a standard, easily programmed tester which measures resistance, capacitance, and inductance between the different test points, to find bad solder joints, shorts, opens, wrong parts, missing parts, parts installed wrong, etc. The only tricky part is the actual bed of nails fixture, but there are shops that churn these out. Asian factories set these up all the time for consumer products quickly and efficiently.
The tests I describe are not nearly as sophisticated as what Boeing is doing, but then the Maslow4 isn’t at risk of falling out of the sky with 400 passengers aboard. It will still detect 99%+ of faults, which is fine for a consumer product but not OK for a passenger airline.
Software flashing and functional testing are often built into the ICT fixture, and this pushes the price up some, but again, Asian factories know how to set this up cost effectively.
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We have twelve pins. Two are 24v power to power the board, two are USB connection to program the board, and eight (4+4) are there to specifically test the stepper motor driver chips that we are worried about. Technically we only need to test the upper one, but I figured might as well check both at the same time.
Are you sending test rig(s) to the PCB fab/assembler so they can initial QA before shipping boards?
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Yes, absolutely. That is the long term plan. Once I have them working smoothly we’ll be able to hand that off.
The goal is to hand of basically everything that we are doing right now at some point, we just need to figure out how to do it ourselves first so that we can hand it off correctly.
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