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Old 29 March 2012, 23:13   #7
prowler
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Join Date: Aug 2008
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Quote:
Originally Posted by SuperNashwan View Post
Next issue: Do I take the working motherboard out of its yellowed case and put it into my old nice white case? Is it straightforward?
Hi Nathan,

First, congratulations on sorting out your A1200/ACA1231 problems.

BTW, it's not possible to be certain whether the Rev.2B motherboard would have been causing problems with the accelerator, even if it were faultless. This is because component tolerances make each case unique.

Now, regarding your plan to transplant your working internals into the shiny white case:

This should only be seriously considered if they are either both Commodore or both Amiga Technologies (Escom) cases. This is because the Amiga Technogies motherboards are modified to accept a PC-compatible internal floppy drive (so you can't even afford to get the floppy drives mixed up in that case).

That said, you'll be pleased to know it is quite a simple matter to swap the cases.

The case is opened by releasing five self-tapping screws from underneath (three along the front edge and two at the centre on either side - one under the front of the floppy drive opposite the eject button and one just behind the PCMCIA slot), then remove the top by lifting the front edge and gently pushing it backwards once it's clear of the keyboard to release it from the catches at the back. (Note that the centre screw along the front edge may be hidden by a warranty sticker if the machine is being opened for the first time.)

Take notes to make sure you know where all the screws and other parts came from and how they should connect or fit back together.

The LED PCB can be removed from the case top by releasing the screws. (Note that the four-wire cable is routed through the hole in the keyboard on that side.)

Be very careful when removing or replacing the screws. The threads in the case are delicate and may be stripped easily. Make sure you use a screwdriver which fits the screw heads exactly to avoid damaging them, and never force a screw unduly (difficulties are usuallty caused by misalignment of the components).

Locate the end of the keyboard ribbon where it connects with the motherboard and prise up the clip securing it in the socket by lifting it at each end. (If this is not possible because access to it is prevented by the RF shield, take a sure grip on the cable and pull it out gently but firmly against the resistance.) Lift the keyboard up slightly at the back and pull it backwards and out from under the tabs securing it at the front. Remove the LED cable from the motherboard header.

Now is the time to remove your accelerator card if you have not already done so via the trapdoor.

Next, you can remove the floppy drive by releasing the data ribbon and supply cables from the motherboard headers, two screws from underneath the case along the back edge and one at the front securing the mounting bracket to the inside of the case through the motherboard.

And remove your CF hard drive/IDE adapter/ribbon cable and hard drive cradle (if fitted) from the motherboard header.

IIRC, there will be no need to remove the RF shield (if fitted) unless you wish to do so.

In this case, carefully prise up the tabs securing it to the motherboard cradle and remove the two screws at the front (one from inside the case at the centre and the other from underneath the case on the left secured by a clip). Lift the RF shield away starting at the back until all the tabs are clear of the slots, then pull it forwards and unhook it from inderneath the motherboard cradle at the front.

Otherwise, just release the front two screws mentioned above and you're now ready to remove the motherboard assembly from the case.

Note: Some machines have a third screw securing the motherboard an inch or so to the left of the bracket which secures the floppy drive inside the case.

Lift up the front slightly until you can get your fingers under the cradle and pull it forwards until the rear sockets are clear of the cutouts at the back of the case and lift it out.

Disassemble both machines as described above and reassemble them after swapping the cases.
Reassembly is a direct reversal of the disassembly procedure.

When reconnecting the keyboard ribbon to the motherboard, replace the front of the keyboard under the tabs at the front edge of the case and lay it down at the back, then pull up the clip surrounding the motherboard socket, insert the cable and then push down the clip to secure it.

Now you know.

Last edited by prowler; 30 March 2012 at 01:20.
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