space invaders tilts when first target is struck

[stevebm1]

my space invaders has decided to start acting up,it just tilts as soon as any target is struck,in switch test it says 07 is stuck on,so I disconnected all 3 tilts,to try and trouble shoot it,but it still gives the same error,ive reseated all the connectors,but still no joy,it's driving me mad,anyone had this or a similar problem before?

 

[stoptap]

Here is the switch matrix chart so you can check switches on the same row and column.

http://www.pinitech.com/switch_database.php?name=Bally_Space_Invaders&printview=1

 

[Moonraker]

Any battery acid damage on the MPU?

 

[stevebm1]

thanks for the replys,and info,there is no battery damage,and I tried it with an alltek board and it still does the same

 

[stoptap]

Sounds like a switch or switch diode stuck.

 

[DRD]

With these old ballys there might be more than one switch at fault. From memory the switch test only indicates the highest numbered one at fault, lower numbered ones may be out too

Also these games have 5 tilt switches, so have you checked all of them ?

I had a similar problem on my vector. I was getting a switch error on a switch that was not even used. the problem was actually on a drop target bank, whilst cleaning it up i had bent a diode wire so it was shorting on another exposed wire, so check all the switches in the relevant row and column

 

[astyy]

I had a similar problem on GOLD BALL cured by replacing the Cap across the Plumb Bob tilt switch.

 

[stevebm1]

finally got some time to look at this again today,and it turned out that even though the switch test said 07 stuck on,it was infact a duff diode on the left outlane switch,took a bit of faffing around with the multimeter testing various switches,but I found it in the end