My xenon will not start a game.It has a new mpu,solenoid driver,power supply.All voltages appear to be correct.Both balls are in the trough.All self tests function properly but occasionly #21 switch failure comes up.Switch looks good and is gapped properly.I have tried other Lamp Drivers.Main and Aux.Sound seems to be good.Even before switch failure came up it would not start a game.All pins look good.

25,the coin switches will add credits but the start button doesn't remove any

I forgot to mention it does boot up.

I just powered the machine up again.7 flashes -everything reset but would not start a game.I turned power off and back on and it booted again.I pushed the self test button and lamp test worked.pushed again and all displays counted properly but top right pop bumper picked up several times during this test.It had not done this before.All solenoids pulled in and dropped out in correct order.Sound worked but was scratchy.switch test shows #21 which my schematic shows to be drop target #4 .Switch looks good,diode tests good.

The start button does nothing after it boots.In self test I can use the start button to change high score etc

I snipped one leg of cap no change.The micro switch meters out good.Both trough switches advance balls in self test.As long as drop target #2 is up I get zero switch problems.

I unplugged j3 on mpu and zero stuck switches.I am in process of checking this out

Both trough switches work fine with balls sitting on them.Found tube entry switch needed adjusted.Fixed that.It does go out of attract mode when start switch is pushed.Now #1 and #3 rollover buttons not registering.Thanks to everyone for helping.

All my switches show open in switch test.I can manually activate each switch and they read and correspond to correct number.The credit start switch functions in test mode,but when pushed in attract mode everthing locks up.

I will call Tom,I will also double check tilt mech.Thanks Everyone

Problem solved.After checking every wire for shorts,checking all diodes and cleaning and adjusting every switch.It still would not start a game.I don't think I would have fixed it without all your input.So thanks to all.The problem ended up being a bad connection on mpu j2 pin 12.Somebody had put a twisted pin in the header and it had an intermittent connection.