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RS485 module where I'm replacing the IC Circuit

I have been struggling a lot with a MAX485ESA IC I bought from aliexpress. What I want to do is replace the component from a rs485 module. For some reason they don´t work and I was wondering if anyone has experienced this? I have tried the following:

  1. Replace with the aliexpress component - fail
  2. Replace with a component from a working rs485 module - works
  3. Replace with the aliexpress component in the working rs485 module- fails

So what I'm thinking is that probably the aliexpress components are damaged but it just seems so strange that all 10 IC are bad. where do you guys buy good MAX485ESA ICs? any ideas of what could be wrong?

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    \$\begingroup\$ 1) The part isn't compatible. Or 2) The 10 parts are bad. Aliexpress is not a reliable source of quality components. 3) where do you guys buy good MAX485ESA ICs - from a reliable source such as Digikey or Mouser. \$\endgroup\$
    – Eugene Sh.
    Commented Apr 4 at 15:58
  • \$\begingroup\$ Maybe the chips are OK but you are using the module wrong. Why not tell how you use the module, like what is the supply voltage, how you connected it to MCU and the bus. You do have three wires on bus with two data and common bus ground? Or maybe they broke when you soldered them, or they are soldered poorly or just placed upside down. We can't guess what might be wrong unless you give the details. \$\endgroup\$
    – Justme
    Commented Apr 4 at 17:37
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    \$\begingroup\$ Anybody in the know who is an EE won't buy parts to be used in an important design from any non-reliable distributor such as maliexpress, peeBay, BangBad or shamazon. In fact, EEs probably wouldn't buy from these "people" for any design no-matter how trivial it is. And, that applies to resistors, capacitors, diodes, inductors, transistors and connectors. I expect that all ten are fake parts. \$\endgroup\$
    – Andy aka
    Commented Apr 4 at 17:41
  • \$\begingroup\$ @EugeneSh. I think maybe all 10 are bad because they are exactly the same model. I will try digikey or mouser, no wonder they were so cheap in aliexpress. I am starting to believe they are fake :( \$\endgroup\$
    – user2808169
    Commented Apr 4 at 18:11
  • \$\begingroup\$ @Justme I added the circuit and also the module where I was replacing the component, sorry I had trouble uploading the images the first time. I checked the pins and they are in the correct position, I will try to solder them better to see if maybe thats the case (if it is I will come back and add a comment about that). \$\endgroup\$
    – user2808169
    Commented Apr 4 at 18:12

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