Hi all, my first support post, please be nice

Stern Lightning 1981, has been sitting for years. It has had mods/updates done through the years (mostly regulator board but test points seem to be within tolerances).

I have removed and cleaned as much as I could and followed "Repairing Bally Electronic Pinball Games from 1977 to 1985 (http://techniek.flipperwinkel.nl/ballyss/rep/index1.htm)", by cleaning battery corrosion (not too bad) and cleaned up and added some new "beefier" supply lines and ground on the MPU.

When it boots, get all 7 flashes and game comes up and plays, BUT I cannot connect both ribbon cables from SB-300 to J5 on MPU-200 as shown, if right side is connected to J5 game will not start or pass "light checks"

This makes sense that the right side of J5 controls 1/2 of PF sounds...

Any help on next steps or troubleshooting is much appreciated, thx in advance.

Jay

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I can physically connect the ribbon cables to J5, but when I plug in the right side, game will not start. Get the quick MPU LED flash.....and then nothing....

Remove ribbon from (right side) of J5, starts np , just lack of sound of 1/2 playfield.

Thanks guys, I verified both cables were okay, and went over locations of pin1 and we seem to be good now! both ribbon cables plugged in and full sounds!!