Can anyone with a Gtb Flipper Parade answer this question from a friend of mine please?

"It awards extra balls for high scores and if you hit the roto target matching a selected top lane. But I believe it should give an extra ball if you make all the top lanes? If so, I don't think any relays activate to award an extra ball? All the 1-5 selection latch relays pull in and the contacts all look ok. 
I think the Sequence Scoring Control relay that awards an extra ball is only activated by the Target relay. I think there must be a break in the 1-5 selection relays that are connected in series. I don't have a schematic and everything I check seems to be ok."

If you own one of these and could shed some light then I and he would be grateful. 

Thanks very much everyone. My friend can now examine the circuit/s that control this and fix it.
All the best!

Great, thanks very much!

It's no better today. Difficult to buy decent solder to use but I'm fortunate to still have a decent bit left from when I worked in the T.V trade in the 70s
Thanks again for the info everyone, I reckon theres enough now to get him fixed up.