Electronics > Repair

What methods do you use to test LM239 comparators?

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Postal2:

--- Quote from: 2N3055 on January 08, 2025, 10:19:48 am ---
--- Quote from: Postal2 on January 07, 2025, 05:17:02 pm ---
LM139,239,339 are the same chip, qualified by operating temperature. I ordered LM339, I did not like that when heated, the chip case can be easily bent.

--- End quote ---

What kind of heat and force did you apply to bend IC case?

New LM339B from TI has same temp range as LM239.

--- End quote ---
I can bend it for you, measure the temperature with a thermal imager and take a photo. Will this advance you in any way or be useful?

2N3055:

--- Quote from: Postal2 on January 08, 2025, 05:28:40 pm ---
--- Quote from: 2N3055 on January 08, 2025, 10:19:48 am ---
--- Quote from: Postal2 on January 07, 2025, 05:17:02 pm ---
LM139,239,339 are the same chip, qualified by operating temperature. I ordered LM339, I did not like that when heated, the chip case can be easily bent.

--- End quote ---

What kind of heat and force did you apply to bend IC case?

New LM339B from TI has same temp range as LM239.

--- End quote ---
I can bend it for you, measure the temperature with a thermal imager and take a photo. Will this advance you in any way or be useful?

--- End quote ---

Language barrier.

What I meant is to ask what the hell are you doing (what kind of abuse) to the chips to be able to bend them.
I'm sure I can bend them if I use hydraulic press on chip that was heated to 400°C for a long time.
But usually IC will unsolder and detach from the PCB before you will bend the case...

Postal2:

--- Quote from: 2N3055 on January 08, 2025, 05:49:05 pm ---... But usually IC will unsolder and detach from the PCB before you will bend the case...

--- End quote ---
No. Due to the flexibility of the case, the legs extend when unsoldering, when you pull the case.


--- Quote from: Poroit on January 08, 2025, 09:27:09 am ---My application used 2 x LM239 to monitor the status of 4 power supplies via attenuators. ...

--- End quote ---
Yes, that's right. When applied to motors, comparators measure multiple thresholds of current consumption, since the MCU cannot handle the overload quickly.

schmitt trigger:
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?

Postal2:

--- 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.

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