Bally logo How to properly mount a Bally
AS-2518-54 Rectifier Board
Bally logo

The Bally AS-2518-54 rectifier board normally mounts on a large metal plate found in the bottom of the pinball machineís cabinet. It uses the metal plate as a heat sink for the two large bridge rectifiers on the underside of the board, so mounting it properly is important.

Follow these step-by-step instructions and you'll be good to go. You'll need some heat sink grease, the mounting screws that came with your board (at least 6 if not all), and a Phillips screwdriver. You can probably find the heat sink grease at Radio Shack if you're in a hurry, or you can get the small tubes as shown in the links below at Allied Electronics. They have a 5-pack of 1 gram tubes, or a bigger 1 oz. syringe.

Hereís what an AS-2518-54 Rectifier Board looks like.

Locate the two mounting holes for the bridge rectifiers.
These holes are circled in red and are tapped for the mounting screws.
I also circled the board mounting holes in yellow.

Practice laying the board in the proper position once, so youíre sure you know where
it goes. You want the two holes that go through the bridge rectifiers to line up with
the holes in the plate. Also make sure the mounting screws around the edge of the
board are lining up with their holes too.

Clean this area well with some alcohol or acetone.

Make a circle of heat sink grease around each screw hole.
Not too big, about the diameter of a dime.

Carefully place the rectifier board in back on the mounting board. You want to get
the board positioned as best as you can without moving it around a lot or you will smear
the heat sink grease all over the place. What I like to do is peek through one of the
two mount holes on the board and locate the corresponding screw hole on the plate. Then
as you peek through this hole, guide the board into place while keeping the screw hole in sight.

Double check your work, being careful not to move the board around too
much. To avoid smearing the heat sink grease, itís best if you can place
it directly into the proper position the first time, without scooting it
around afterwards.

Next, start the two mounting screws that go through the bridge rectifiers.

Continue screwing them down, but not tightly yet.

Now locate and install the rest of the mounting screws along the perimeter of the board,
but donít tighten them all the way yet. Since all the screws are a little loose, you have
a little bit of board movement available to help locate the mounting screw holes on the plate.

Once all the perimeter screws are in place, now tighten the two bridge rectifier screws.
You want them nice and tight so it spreads the heat sink grease into a nice thin layer.
Just be careful that you donít strip the threads out of the mounting holes.
Then tighten up the perimeter screws after that.


One word of warning. The mounting screws protrude way past the bottom of the
board, so be careful where you place this assembly, or you may scratch up a
nice table or something.

[Steve's Page] [Pinball] [Bally Pinball]

Created 11/9/11 - Last Modified 11/25/11 - Steve Kulpa Mail Icon Nolensville, TN
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