Make a stacked-socket adapter to run two 2716s on a stock -17 board

Steps

• Take four 24-pin machine-pin sockets. On two of them, wire pin 21 to pin 24.
• On those two modified sockets, solder a wire of about 10 cm to pin 18, join the two wires and fit a test clip on the end.
• Clip pins 18 and 21 short on the modified sockets so they do not plug into anything (you can clip them on the lower sockets too).
• Plug each modified socket into an unmodified one, then fit the U2 and U6 2716 EPROMs in the top sockets.
• Plug the stacks into U2 and U6 and clip the test lead to the side of R14 nearest the ROM sockets.

Systems

• Bally MPU AS-2518-17
• Stern MPU-100

Related tips

• Making a 9316-to-2716 adaptor socket
• Failed 9316 ROMs on a -17 board: use a socket adapter instead of modifying
• Mod1: two 2716 EPROMs at U2 and U6 on a -17 or M-100
• Mod3: 2716 at U2 with a 9316 at U6 on a -17 or M-100
• Test EPROM: the least an MPU needs to run it
• U9 pin 2 (halt) is not high
• -17 and M-100 boards cannot run 1979-1985 games without modification
• A Stern M-200 set for 2732s runs any Bally or Stern game 1977-1985

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Three, Clay Harrell (pinrepair.com)