Products > Test Equipment

IC testers, do they work?

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Fungus:

--- Quote from: Someone on August 08, 2023, 11:41:23 am ---Can they cycle through some states and guess what sort of device is attached? yes. Can they cycle some states and check pass/fail against a specific pattern? yes. But thats about it.

--- End quote ---

Right, so imagine I have a box full of used 74-series logic chips to repair old arcade machines.

I pull out one that identifies as a "7400 Quad 2‑input NAND Gate" and it says "74LS00" on the back then there's a good chance it's a working chip. If it doesn't identify the chip then it gets binned and I look for another one.

ie. This device is doing some level of "testing", not just identifying chips, hence then word "tester" printed on the front of it.

Is it guaranteeing the outer limits of the datasheet specifications? No of course not, but I don't think there's any gadget for that. These are cheap, they're fast, they can save a lot of wasted time, they're testers.

(And OP can be confident they're not a scam or complete waste of money, which is what he was asking).

Kim Christensen:

--- Quote from: Someone on August 08, 2023, 11:55:12 am ---So when you say a "tester" which model/style are you referring to? what information does it provide? is its documentation available online?
There are a range of products out there with wildly different capabilities, the device you refer to may well have much more intelligence than the example the OP is asking about. What passes as "ok" in these cheap testers doesnt always function in real circuits, thats the biggest problem as it provides a false sense of security/validation.

--- End quote ---

Here in the video I linked previously, you can see it fail a very basic test on a LM339 when the guy lifts a pin.

I've seen many techs be led astray with diode check. One example was a 1n4007 diode. Looked great on diode check, but as soon as a bit of current was passed through it (300mA) it's forward voltage drop would increase to 3-5V...

As long as the tech knows the limitations of the tools he's using, then it's OK. I don't think the IC checker that the OP linked is worth getting since the tests & devices are so limited. Besides, most parts I want to check are soldered in. Usually I've figured out that it's bad by how it performs in circuit before I remove it.


alm:
After reading this, if anything, I'd consider the Retro Chip Tester Pro if you're into retro computing because of its breadth in support for forms of memory, or the Tauntek tester ledtester linked to because of its more thorough analog DC tests. The Aliexpress ones don't seem worth it.

factory:
We had a old PC with a EPROM programmer built into it at work, I was not impressed by the logic IC test function, more a quick check, it could not identify between types with same pinout, with slightly different function, output type, speed etc.. The logic ICs were ex ICL and marked with in-house letters instead of the 74xx number.

David

Someone:

--- Quote from: Fungus on August 08, 2023, 12:50:14 pm ---Is it guaranteeing the outer limits of the datasheet specifications? No of course not, but I don't think there's any gadget for that. These are cheap, they're fast, they can save a lot of wasted time, they're testers.
--- End quote ---
If they cant say what was tested then its just a black box, I don't put any trust in a low cost widget that calls its self a tester yet provides zero information on what that test is or what the pass/fail criteria are. Hence calling it more appropriate to be described an an identification device.

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