Thirty-year-old pinball machines still play like nothing else. Which used pins to buy, and what to check before you pay.

Start with the CPU board batteries. Williams WPC, Data East and Stern Whitestar games keep their memory on AA batteries mounted on the board, and leaking alkalines kill more pinball boards than anything else. Ask for a photo of the board around the holder. Then ask for a video of the attract mode to check that every pixel or segment lights, and run the game's diagnostic menu if you're there in person. Lift the playfield and look for rough soldering and blackened wiring. Last, walk around the cabinet for cracks from careless moves.

Measure your doors, stairs and vehicle first, since many cars come up an inch short. Take out the balls and anything loose, fold the backbox down on newer games or take it off older ones, and put foam or cardboard over the glass. Then remove the legs. For a tight doorway you can unbolt the backbox and turn it about 45 degrees over the playfield while a second person holds it. A modern Stern is advertised at 27 inches wide and about 250 to 260 pounds, so plan on two people.

An alphanumeric display is a row of segmented characters, usually orange neon plasma, that can show letters and numbers. A dot-matrix display, or DMD, is a grid of individually lit dots that can draw text and animation. Data East put the first one in a game on Checkpoint in February 1991, and 128 x 32 dots became the standard size. Plasma displays of both kinds run on high voltage. With AC/DC in 2012, Stern switched its US games to LED dot-matrix displays.

HUO means home use only. The seller is saying the game was never on location in an arcade or bar, only in a home, and that's common for games made after 2000. It usually means less wear, but it's a claim, so look at the flipper areas in the photos anyway. Shopped means someone has gone through the game, cleaning and repairing or replacing worn parts. Unshopped means it's as it came off location, unrepaired. When a seller says shopped, ask what was done, because it can mean a quick clean or a full restoration.

Many solid-state games keep their settings and high scores in memory backed by batteries on the CPU board. WPC batteries always leak electrolyte in the end, and the leak corrodes the traces under the holder. On Stern's Whitestar boards, alkaline damage is often beyond economical repair. The usual fix is a remote battery holder mounted below the boards, or a lithium cell or memory capacitor instead. Williams moved the holder off the CPU on its WPC-S boards, then put it back on WPC-95. Stern's S.A.M. games from 2006 use a lithium coin cell that isn't prone to leaking.

Chicago Gaming Company makes licensed remakes of 90s Williams and Bally games. Medieval Madness came first in March 2015, then Attack from Mars in June 2017 and Monster Bash in November 2018, and it lists a Cactus Canyon remake too. Remakes are newly built games, and some have color displays where the original had an orange plasma DMD. If you want an original, check the listing for the Williams or Bally badge, the year on the serial plate and the original display. Our eBay picks leave remakes out of the original games' pages.