Mac Plus
This Mac Plus is the oldest Mac I've owned, having been built in 1986. It ran System 6 and 7.1. The only thing I ever had to do to it was install a PRAM battery:
Having removed the battery from your Mac, you'll notice that it takes an Eveready type 523. Well, the bad news is this; the type 523 is no longer manufactured. Don't despair! You can easily replace this using a 4.5V CMOS battery readily available from computer/electrical stores. Here's how:
Before you start, you should know that opening up a Plus, or any device containing a CRT is dangerous! If the Mac has been switched on any time in living memory the chances are that it still has enough juice in there to give you a pretty hefty electric shock. If you are careful and follow the proceedure properly then you will be fine.
You will need the following items:
- A small flat blade or torx scredriver with a long shaft
- A piece of cloth such as an old table cloth or dust sheet
- A soldering iron
- Solder
- Wire cutters
Set out the cloth on a flat sturdy surface and put the Plus on it. Now remove the two screws just above the ports.
Now put the Plus on the cloth with the screen face down. Remove the battery compartment cover, remove the battery (if present) and unscrew the screw inside.
Look for the two screws located right in the depths of the carry handle, you might need to use a torch. Use the screwdriver to remove the screws (now you see why it needed to be long!)
Now, just give the case a little tug and it should slide off nice and easily like so:
Hold the case and use your thumb to press against the battery compartment if it's a bit stuck.
Remove the paper shield from the bottom of the logic board and put it somewhere safe.
Next, sit the Mac upright again and using pliers, remove the plastic clip that secures the shielding to the analogue board. Locate the two solder joints on the reverse of the analogue board that attach the battery compartment. They are helpfully labelled - and +.
Lie the Mac down on it's side so that the analogue board is uppermost. Get your soldering iron warmed up.
Solder the wires to the analogue board where the solder joints of the battery compartment are.
Try and route the wires between the battery compartment and the power switch, otherwise they will get trapped in the case when you put it back together. Attach the battery to to a surface (like the battery compartment) inside the Plus. Mine came with a nice self adhesive velcro pad for this purpose, but if yours doesn't, you could always use some double sided tape or a hot melt glue gun to affix it.
Now that you've done the hard part, put the plastic clip back in to secure the plastic shield to the analogue board. Also, don't forget to re-fit the paper shield that sits under the logic board.