Fake LM741
From Leo's Notes
This page was last edited on 16 August 2020, at 17:17.
I bought 20 LM741 off Ebay in summer of 2019 from the seller "satisfyelectronics" and it turns out that only 3 functioned as an op-amp. After questioning my sanity for an entire afternoon, I eventually set up a dead simple unity gain circuit and tested every IC I had and only 3 functioned as expected.
All the non-functional ICs have relatively decent laser etching and it is indistinguishable from the chips that do work.
The entire order for the 20 LM741 was $1.88 USD with free shipping. Most likely, these are tested rejects.