Well said JDW. Seriously, there are few compact Macs out there of this vintage that have never had some part replaced. And most likely they were replaced with a part which was not original to the Mac that rolled off the assembly line. Particulalry if it was repaired by a third party service center and not Apple. And Apple themselves revised the replacement parts over the life of service, in large part because they under-specced the part to begin with which is why it failed in the first place. Apple did not officially discontinue service on the first compact Macs until 1999. By that time, they were hardly providing the same componet replacement parts as originally installed in the Mac 15 years earlier.
I have a stock 128K Mac made during the 13th week of 1984. Everything about it is exactly identical to the parts which rolled off in the very first Mac (as far as I can tell). But it doesn't work and was never repaired. So what good is it? I maintain it in that condition as a museum piece, but every now and then, I pull it out and try to source the problem for repair, because if I ever sell it, nobody will care that it's 100% original if it wont turn on. However, If I ever do figure out why it doesn't work and repair it, I will photographically document it and keep the original parts for sale with it. A working Mac with full documentation of repairs made, as well as the original parts is worth far more to a collector. This allows them to use it, while being able to fully restore it to factory condition should they desire to do so. Actually, that's incorrect as it is highly unlikely using parts available today that one would ever be able to restore it to working factory condition. Even By the time the Plus rolled off the assembly line, parts Apple had used had already been discontinued and become unavailable, and many repair manuals recommended salvaging those parts wherever possible. One could certainly cannibalize another vintage Mac, but as JDW points out, those parts are in a similar state of degeneration, and will not be functional for long in their aged condition.
I have a stock 128K Mac made during the 13th week of 1984. Everything about it is exactly identical to the parts which rolled off in the very first Mac (as far as I can tell). But it doesn't work and was never repaired. So what good is it? I maintain it in that condition as a museum piece, but every now and then, I pull it out and try to source the problem for repair, because if I ever sell it, nobody will care that it's 100% original if it wont turn on. However, If I ever do figure out why it doesn't work and repair it, I will photographically document it and keep the original parts for sale with it. A working Mac with full documentation of repairs made, as well as the original parts is worth far more to a collector. This allows them to use it, while being able to fully restore it to factory condition should they desire to do so. Actually, that's incorrect as it is highly unlikely using parts available today that one would ever be able to restore it to working factory condition. Even By the time the Plus rolled off the assembly line, parts Apple had used had already been discontinued and become unavailable, and many repair manuals recommended salvaging those parts wherever possible. One could certainly cannibalize another vintage Mac, but as JDW points out, those parts are in a similar state of degeneration, and will not be functional for long in their aged condition.