Samsung CLP-500 problem

Resistors? You mean the smart chips?
Here's something I found over the last few years of dealing with these newer laser printers.

Say for example you had a 13,000 page factory toner, you replace it with a 20,000 page aftermarket refill, but you trade off the chip. There are small case triggers that read the toner size (I still haven't figured if it's internal or external) The chip is programmed for a specific cartridge size. The carts don't match, the chips won't work.
Also, certain printers will recall chips that have been used, and won't let you reapeat chips until you have gone a certain number (like it has to have 4 or 5 different chips before you can reuse the first chip).
So options to get around it.
I found in the Dell printers, if you go through the menus, there is a setting that allows you to bypass using factory cartridges, I don't know if Samsung has the same menu settings, but it's worth digging through the layers.
2) Put the chip that came with it back in, and see it it will work.
3) Break down and buy a factory cartridge. I know this is the least attractive option, but it will determine if it is a read sensor, a firmware/software error, or something else.

The whole smart chip imbedding happened about 7 years ago as a settlement on a lawsuit.