Electronics > Repair
What methods do you use to test LM239 comparators?
<< < (4/4)
2N3055:

--- Quote from: Postal2 on January 08, 2025, 07:19:35 pm ---
--- Quote from: schmitt trigger on January 08, 2025, 07:04:17 pm ---I also believe that something is becoming lost in the translation. You cannot bend a DIP or SOIC package, it will crack long before it actually bends.
Perhaps you meant something else?

--- End quote ---
No, I'm trying to find these chips in boxes now, I'll find them and take a photo. I can wrap them like hot chocolate. LM339, should be TI, but I don't remember exactly.

--- End quote ---

OK I think I understand now.

Plastic of the case behaves like thermoplastic, getting soft..
Yes if you have that, those are very fake chips.

I assure you that original chips  by any real factory is made from different material that will not behave like that.
Not only TI , but any real factory even from third world countries.
Zero999:
My go to is a Schmitt trigger oscillator. Here's an example of one I simulated, to test this simplest model I could come up with for an open collector comparator. The LED should flash at about 1Hz. You could build 4 to test your LM239.
Postal2:

--- Quote from: Zero999 on January 08, 2025, 08:39:23 pm ---My go to is a Schmitt trigger oscillator. Here's an example of one I simulated, to test this simplest model I could come up with for an open collector comparator. The LED should flash at about 1Hz. You could build 4 to test your LM239.

--- End quote ---
Yes, this looks very much like what is needed. Thank you. I would like to determine the leakage of 1 MOhm between arbitrary points of 4 comparators, I will try.

--- Quote from: 2N3055 on January 08, 2025, 08:22:27 pm ---OK I think I understand now. ...

--- End quote ---
I haven't found the chips themselves yet, but I did find a photo of me soldering the LM339. When I find the chips, the markings will be clearly visible.
Navigation
Message Index
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod