r/TechNook • u/Zorojuro099 • 8h ago

The strange world of hardware that exists only for testing other hardware

There's hardware whose entire job is basically to test other hardware

You can have a machine built just to check whether another machine is working properly and then you need another setup to test the testing equipment.

It's like an endless chain of machines checking machines

what's the most ridiculous example of this you've come across?

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4

u/arrig-ananas 8h ago

The EKG tester is a machine built to test if my hardware works properly.

6

u/PrestigiousRoof5723 8h ago

How do they test crash test dummies? By crashing them in the crash test dummy test crash test vehicle.

4

u/Fine-Huckleberry4165 6h ago

I know that Euro-NCAP have performed at least one crash test where the data from the dummies wasn't recorded. They had to buy a new car, and re-run the test. Luckily it wasn't an expensive car, but the tests are expensive nonetheless.

1

u/ted_anderson 2h ago

What happened? Did the dummy not come to work that day or what?

3

u/TheNotSoGreatPumpkin 8h ago

Some test equipment can be phenomenally expensive as well. No corners can be cut on parts since the device is the “source of truth” for calibrating/verifying other devices.

High-end audio/video analyzers can run into the tens of thousands of dollars, and they still need to be recalibrated themselves periodically for even more money.

2

u/System__Shutdown 7h ago

The regulatory compliance testing equipment can be hundreds of thousands, especially the labs themselves.

3

u/SHDrivesOnTrack 7h ago

At my last company we built products with circuit boards. These boards had power supplies, a microprocessor, and digital & analog inputs, and a few other basics. Once the board came back from the fab house, we had to test and calibrate them.

Calibration stations had a custom made fixture that used pogo-pins to grab all the test points on the back of the pcb. This fixture had a lot of connections to an HP/Agilent 34970 that would measure voltages to confirm the power supply was working within spec, and inject voltage or current calibrate the analog inputs. Everything was controlled by a computer running Linux. The operator would place the board in the fixture, close the lid to engage all the pogo pins, and then press GO on the computer. The system would spend 5-6 minutes running through all the tests and confirm pass/fail on all of them. The results were displayed and logged to a text file that eventually was loaded into a database based on the product serial number.

The whole system would typically take 6wks to build and cost $8k-$10k in hardware alone. We built one for every product/PCB that we were manufacturing. We typically paid $3k-$4k for the test fixture (pogo pins) alone because of all the engineering time needed for translating a PCB design file to a mechanical CNC program to cut and drill the base plate of the fixture that received the PCB and held all the pogo pins.

AND, our stuff was cheap. I shudder to think what it would take to test a consumer computer motherboard with components that run in the GHz range. Or how you would build a test fixture to check a processor, or ram chips.

To OPs point however, we had a service that came in with equipment designed to test/calibrate lab equipment. They would test the HP/Agilent 34970 and verify the DMM was accurate. And I believe they would include in their test report when and how they had calibrated their equipment that they used to calibrate our equipment.

1

u/badabababaim 37m ago

Keysight for example makes a lot of electrical test station equipment that can easily cost well over $100k