Ok, so we have to be honest here, or at least, I have to be honest with you.
Your LC-8500 BTX is complete garbage. I'd be surprised if that unit could safely power a light bulb and no, I am not joking about that. It's a door stop. A PSU shaped object, plain and simple. You would be well advised to throw it directly in the trash and never use it with any hardware you have even the slightest concern for or that you value at all. It is literally a dumpster fire waiting to happen.
You CX430 is also a very poor quality unit. I've seen a LOT of those older CX units completely toast the systems they were attached to, including for some veteran members around here. Besides which, it is definitely ALSO underpowered for any system using an RX 470 that should only be used with at least a decent quality 450w or higher capacity unit. It also has to be pretty old because that model hasn't been manufactured for a pretty long while now so unless it was purchased used or was very old stock sitting on somebody's shelf for quite some time, it wasn't purchased recently.
Your High Power 650w unit is the best of the bunch, and even that one is relatively mediocre, but it's definitely better by far than the other two especially the LC-8500BTX. Even at 4 years old I'd trust it far more. It uses a decent platform, even on the cost down version of it as this platform is used by several brands for various models. High Power is an OEM, which means they actually design and make power supply platforms which they supply to other brands who are not power supply OEMs, like Antec, EVGA, Be Quiet, Thermaltake, Corsair, Fractal Design. NZXT, Gigabyte, MSI, etc. None of those companies design or make power supplies, they have companies like High Power, CWT, Seasonic, Super Flower and FSP do that for them basic on the platform and specifications they want, and then slap their own branding on them.
But if that unit is more than 5 years old or was used when you bought it so you don't really know how old it actually is, then it might just as well have problems due to age. And, a weak or failing power supply can absolutely cause one or more memory modules to not be recognized or cause errors.
I think the VERY FIRST order of business for you should be getting a good 550w or higher power supply. The following resources should be helpful in determining whether a unit is worth considering or not.
Below you will find MY standard list of recommended power supplies and beyond that this thread is intended as a landing place for questions or discussions regarding specific units, platforms or related PSU tech, all of which are all welcome to be discussed here. If it's related to power supplies...
forums.tomshardware.com
PSU Tier List will help you to choose the best PSU out of hundreds of models on the market. From budget to the highest end Power Supplies.
cultists.network
RAM generally, USUALLY, doesn't just "go bad". It can happen, but it is not very common. Motherboards, different story. Those definitely can fail at any point, but it would be somewhat unusual for just one DIMM slot to suddenly stop working. Which slot was it that started having problems?