I would think that at 1/4in it should be possible to correct using a long cabinet clamp diagonally to true the cabinet against the longer diagonal measurement. It may be necessary to remove/relieve the bottom board & loosen the corner quads to ease the correction. Should be achievable in a few hours at most.

Unless they glued the bottom board in.....

I had that problem with a wide body Big Game. I'm like "how do I fix this?" It sort of fixed itself. I was in process of of restoring the cab so I had stripped it down and took it out to the back porch and stood it up on end to work on the bottom and I also needed to put the play field glass back in place.

And, lo and behold, when I put the play field glass back in and stood the cab back up I discovered I was square again. So, I'm guessing it was just normal flexing, or flexing with old dry joints.

I cured the problem by bonding (with Gorilla Glue) and screwing a 90 degree cabinet brackets (from the hardware store) on the bottom at each corner and I also removed the two inside wooden corner pieces at the player end of the cab and reglued them.

My cabinet was/is a nice cab, but thebefore/after difference in how solid it felt when being moved with the dolly was tremendous.

I'm still in process of getting this pin back together so I can't offer any info. if game play will be affected, or not.

I advise caution about bonding the corner brackets on the bottom of the cab because (1) they will not be original and (2) they may affect how the pin plays when being nudged.

P.S. I have another standard sized pin and noticed it was out of square by how the two apron hold-down screws differed in distance from the edge of the lockdown bar. But through play and nudging, it has returned to square condition.

You might try standing your cab on end, and by using your glass as your gauge, see if it will square up for you.

Good luck. I would like to hear if any of this works for you.

EDIT: Like a fool, I did not read down far enough and read the part about the ply wood strips being Gorilla glued in. You may have to chisel those and do another re-glue. At the very least, if me, I would be contacting the "woodworker?" who did this kind of work and see what they are going to do about it.

Go to Harbor Freight and get an oscillating cutter or plunge cutter. HF's unit is only about $20.00. Cutting blades may be extra.

Gorilla glue will cut fairly easily and the plunge cut blade will let you get underneath the plywood strips and do a cut-release of the bottom if you need to. you can also use this tool to cut your corner braces away form the cab.

HF's Multi-function power tool.

It is the best $20-$30 I ever spent.

http://www.harborfreight.com/catalogsearch/result?q=multifunction+power+tool

Like this Mikita

0eb77e61-05b8-462f-9fc4-0094d5e2aea4_1000 (resized).jpg

Was it the first cabinet they ever built? I can't imagine how they would not get the cabinet absolutely square during the assembly. I've replaced panels on a Gravitar cabinet, and built some new cabinets, and I realize how tricky it is, but it's critical.

Here's what I did with my Roto Pool cab and it seemed to work.

Ted

IMG_1880 (resized).JPG

If his bottom board is already glued in this won't work!

Read post #7 and post #10.

from how i read it and correct me if i am wrong. the OP got a oem cabinet that was repainted to replace the bad on he had.
the seller replaced the cabinet bottom panel and glued it in or did he glue new wood strips along the edge? that would matter to re-square the cab
who was the seller?

i know who and i saw that cabinet first hand. the bottom was done poorly. but i never would of checked for square either so don't feel bad. bottom panels are easy to replace but if done right they don't need to be glues in.
you might get lucky with novaguys method if not pm me and maybe i can help you out

Glad to see you got it done.mine was a real pita to do but it's good now.

Ted