Imo the main issue, is that these things are so cheap that replacement is cheaper than repair labor + cost of parts.
My fridge also had some kind of fault with the drainage tube (kept freezing up) but there's simply no way to access it. The back panel is not removable.
> PCBs that have been manufactured for decades ... same designs.
Absolutely not the case. Go and look up any washing machine control board. They're different for almost every model.
Washing machines & fridges may be better; I've never had to take one apart.
The only good solution to this problem I've come up with is requiring manufacturers to dispose of unwanted appliances for free. That way they have at least some incentive to make them last for a long time and be easily recyclable / repairable.
To be honest, even if you can't find a PCB replacement, a faulty PCB can be fixed by inspecting the components and/or replacing them. Usually it costs only a couple of dollars and an hour of soldering time, less if you are good at it.
Microcontrollers obviously are not as easy, but as luck would have it, my old (early 2000s) machine doesn't even have one - it is driven by those rotary encoder dial thingies that move in a circle and open/close various traces to begin/end program steps.
That's a pretty steep DIY requirement. Wonder how robust the market is for these kinds of repair skills. Hard to know when you have a problem like this, who to call about it, and how much it'll cost to fix.
Yeah right. Maybe if you're lucky or it's all low power stuff but circuits aren't generally designed to isolate failures. If one thing fails it will often cause other components to fail invisibly.
And yes I have tried it. The main transistor on an amplifier I had blew. Replaced it. Still doesn't work.