Quite a while ago I did a repair to the front bottom edge of my F-14 Tomcat. Damage is what is often seen....broken and delaminated plywood. At the time I did not document how it was done and since I'm repairing a Centaur for a friend with similar damage I thought I would pass this along.

Here is the finished repair on the F-14...end result!

F-14 Cabinet repair.JPG

So. The early Bally Solid State machine lower cabinets were made mostly of 3/4" plywood. However, the back of the lower cabinet was made of particle board and susceptible to damage. The first photo below is of the back of Centaur I'm working on for a friend. Note the typical damage to the particle board most likely caused by loading and unloading. These are the before surgery photos...

Centaur Back Damage 1.JPG

Centaur bottom back.JPG

If so inclined, the entire back of the lower cabinet can be removed and replaced with 3/4" plywood. In this case, like my F-14, I chose to only repair the bottom portion. Note that inside the cabinet, there are brackets that support the legs bolts. To avoid the actual brackets, I slice the cabinet 2.5" up from the bottom. The slice is done with a circular saw set to 3/4" depth of cut. Once the slice is done, the damaged wood is removed and a new piece of birch finish plywood is cut to fit. The piece is secured to the cabinet with wood glue, finish nails from the sides and there are two 3" wood screws inset from the bottom. The wood screws along with the glue will provide shear strength. I cut the 1/4" groove for the cabinet bottom panel to fit into very slightly larger the necessary. After the initial glue is set up, I will turn the cabinet on its back and flood this joint with wood glue.... Finally everything is clamped for the glue to cure... More to follow in the next few days...

Centaur Cabinet Slice.JPG
Centaur damage removed.JPG
Centaur new wood.JPG
Centaur screws.JPG
Centaur clamped.JPG

Next Steps... Back of the cabinet was first belt sanded to remove the rough look. Next a thin layer of Bondo, then sanded and then a coat of Primer (just sprayed) for a final check of the finish.

Lower Cab Back Bondo-26.JPG

Lower Cab Back Primered.JPG

And, the finished product....

Back of Cabinet finished.JPG

I've made several cabinets. Most notably was one for a ground up KISS restore. Almost all can be accomplished with a table saw. Trickiest cut is the angle on the sides of the bottom cabinet. For those I use a circular saw with a straight edge for a guide. For the cabinets I use 3/4" birch which has a nice smooth finish.

New Cabinet 2.JPG

New Cabinet 4.JPG

Don't recall specifically where I placed the new bumpers, but looking at the photo I'd guess they are in the new piece for the bottom two, and yes, I believe the plywood will hold up better than particle board.

On another note, I did note show any photos of the bottom of the KISS cabinet. Instead of the typical 1/4" bottom material that is routed in with a 1/4" gap at the bottom, I chose to route the bottom of the cabinet 1/4" into the walls by 1/2" from the bottom. Then I used 1/2" plywood for the bottom. The result is a much stronger bottom that is flush with the bottom edges which will prevent chipping from dragging in the future. The result inside the cabinet is the same as the original. I chose this route because these days we move games with hydraulic lifts the stress the old design.

If you have a game with the bottom falling out, you can route the 1/4" lip at the bottom away and remove the old floor. You will end up with a 1/2" routed bottom and then you can just glue and nail in a new piece of 1/2" plywood.