That's great, I think I might know the reason. That means it never worked since it was updated for Factorio 2.0. I found another mod that makes additional recipes available in the EM plant, it seems like adding them to the category electronics is necessary. I don't want to push a possible fix to everyone before I'm sure so I would really appreciate your help with a little test before.
- Open your Factorio folder, the path depends on your operating system, you can find it for Windows, MacOS and Linux here: https://wiki.factorio.com/index.php?title=Application_directory#Locations
- Open the folder "mods", then unzip the file "CheaperModules_1.0.5.zip". If it worked correctly, a new folder "CheaperModules" should be created. If it worked correctly, delete the CheaperModules_1.0.5.zip file so Factorio gets the mod from the new folder (don't worry, if the fix does not work you can download the zip file from the mod manager again anytime).
- Open "data-updates.lua" in the CheaperModules folder, any text editor should be able to do that. In line 21 you should see "energy_required = 10". Please add a comma (,) after the number 10, then press enter to create a new line.
- Copy this into the new line (it should be line 22, please make sure there is no comma to end this line): category = "electronics"
- Save your changes to the file (Ctrl + S in most editors), start Factorio, make sure you activated the mod and check ingame if the quality tier 1 module is enabled in an EM plant.
If only the quality 1 modules in enabled in the EM plant, all the others are not possible in the EM plant but every module can be crafted by hand and in the normal assembly machines, we have a fix that I can release as an update for everyone.