Mhmm. And I suppose you have a PHD on assembling A1200 towers, eh?
No, but I am a Class 4 Electronics Assembler who has been doing electronics assembly for over 20 years.
And of course, during those 20 years of expreience, you learned the one true way to mount an A1200 motherboard in a tower? The A1200 was never designed to go in anything other than a console case. There is no right or wrong way of doing it. There are no books or courses to study. Only testimonies by other users who have taken up the challenge.
There is absolutely no great skill required to assemble an A1200 tower
WRONG ! Actually, a great deal of skill is required to properly assemble an Amiga 1200 Tower of Power.
Again, there is no "proper" way of carrying out this work. There are things one can do to make it a more successful project, and things one can do to try not destroying any part of their computer. I have done it myself, and while it does require more skill and dexterity than assembling a standard PC, it doesn't need a great deal of skill at all. A decent hand with a hacksaw, drill and soldering iron coupled with a bit of cop on will get you through it just fine.
The only part which requires attention is properly dealing with internal cabling in tight spaces, for the sake of better air-flow.
WRONG AGAIN ! The first thing you must concider is the case. You can NOT just use any case for an Amiga 1200 tower. The PC case that you use must fit the Amiga 1200's motherboard and any expansion hardware that you will be adding.
No disrespect intended, but if you're stupid enough to buy a case that's smaller than the parts you're putting into it, you would be too stupid to even think of attempting something like this. No PC case will actually fit the A1200 motherboard, all you can do is buy one bigger than the board and improvise.
Also, the back piece, that the PC cards would normally be screwed to, must be removed.
No, it doesn't. And notice I'm not obnoxiously shouting "WRONG AGAIN!!!" If you are a little creative with the positioning of the board, the slots at the back will not get in the way, and will even line up with any PCI or Zorro busboard slots you may wish to use.
Then a custom made piece of sheet metal is riveted or screwed to the rear opening. The case that you use MUST have a sub-chassis.
*Sigh* No it doesn't. It may very well make things easier, but you can quite successfully install an A1200 motherboard in a standard one-piece tower, the only modifications required to the case being the cutting of a slot for the original sockets of the 1200 and the removal ot the motherboard mounting plate.
It must be as long and wide as the Amiga 1200's motherboard and any board plugged in. Holes are drilled into the sub-chassis and stand-offs are installed. Then the Amiga 1200 motherboard is firmly screwed onto those stand-offs.
Again, you deserve to fail by your own devices if you've bought a case too small for the computer you're installing in it. The motherboard can be secured to brackets mounted anywhere they're needed, and doesn't need a mounting plate at all.
Any addon board that is plugged into the "trapdoor" expansion port must also be mounted on stand-offs.
... Because they'll also be mounted on the stand-offs designed for them inside the original A1200 trapdoor space? Any device designed to be mounted in the trapdoor slot will be happy to sit on top of the trapdoor edge connector in a tower with maybe a cable tie or similar to stop it from moving too much. If possible, maybe a screw through a hole for additional security onto a bracket mounted nearby, but you can get away without it.
Yes, it requires a certain level of skill, but we're not talking about replacing an on-board SMT chip or anything. What's the problem? And what's the problem with using an internal scandoubler? I've used one in mine for years without a single problem.