I have a Canon MX700 all-in-one printer. I have written about it before. It went wrong and would do nothing but issue a sullen error 6a80. I discovered a way of clearing the error but still could not print; I remarked:
I now think that somehow cleaning up this part of the printer (which is hard to get at) could fix it.
This weekend the time came to prove it, or else to chuck it away. I should have thrown it away. Even though I pretty much fixed it, the time it took and the frustration it caused was really not worth it. Well, it could be worth it if you enjoy such things as a hobby; I am not sure if I do, but I do hate throwing stuff away that can be made to work with a bit of effort, so I guess I get some satisfaction from the process.
Technically of course the correct advice is to get a machine like this fixed by an authorised Canon service engineer, but this is not cost-effective for a three-year-old cheapish all-in-one inkjet printer. It might well have cost more than a new printer of better specification. A skilled engineer would have worked faster than I worked; but you have to get the machine to her and back again; it still takes a certain amount of time to strip a machine down, clean it up and re-assemble it; a professional engineer would probably have replaced parts that I was happy to clean up and re-use, so there would have been a parts cost; and there is an overhead of invoicing and so on; it is not surprising that the costs mount up.
My further observation is that machines like this which are mostly clipped together are not designed for extensive servicing. It is hard to take it apart without breaking a few delicate plastic clips or tabs. I guess once you learn exactly where to tug and how hard to press you get better at it; but clip on parts are not ideal if you plan to remove and re-assemble them with any frequency.
If we were serious about reducing waste we would address this. For example, if you require manufacturers to offer extended warranties as standard, then it is in their interests to make products that are more reliable and more fixable.
In the meantime, fools like me waste time fixing modern plastic junk that should be thrown away.