Hi All, I've been bringing a Gottlieb Top Score back to life over the last few weeks. This really was a barn find machine and has been totally out of action for 5-6 years. It's pretty much running well now, but I'm left with a couple of annoying issues I can't seem to resolve.

The first and more important is, I can't seem to get the backglass bonus balls to score absolutely consistently and it doesn't score the odd one. Think I've cleaned and adjusted all of the relevant switches and I've taken the back out and realigned the ball ramps so the balls run properly in the channels. The supporting brackets for these channels are not too strong and seem to bend down over with the force of the balls being applied. I have improved matters a lot but I can't seem to get it 100%.

The second issue involves the credit or replay unit. This pin has had a free play button added and the replay unit wiring and switch removed. Personally though I do like to use my pins as big piggy banks and like the experience of adding credits with coins. So I dug out an old coin mech "readjusted" it to accept our new £1 coins, also found an old Bally coin slot microswitch in my spare parts and with a bit of fiddling reconnected the replay unit wiring to this switch and fitted the switch under the coin mech. It all works fine, however whatever I do I get 3 credits per coin. Again I've gone through the schematic and cleaned and adjusted all relevant switches (paying particular attention to the score motor switches) but I can't seem to get it to acknowledge the credits per coin settings.

I'm hoping for suggestions on troubleshooting these issues, particularly as this is my first Gottlieb!

Thanks for your replies, in answer to HowardRs question, yes the W relay does activate when a coin is inserted. I will look at Rolfs post in more detail when I have finished painting the house which is my job for the next couple of days! What I want it to do is to add 1 or 2 credits according to how the credits Jones plug is set. I know this isn't an important issue, but I do like things to work as they should.

Rolf,

Top Score has a backglass animation for accumulating the bonus score. Balls are fired up from a bottom rack into a top rack and when the ball in play is lost or a bonus award hole is made each ball is fired back down to the bottom rack and 1000 points is awarded for each ball (2000 on the last ball in play). I cannot get this working consistently, it occasionally misses scoring a 1000 points and it's not the same ball on each occasion. On the last ball it occasionally awards 1000 instead of 2000. Again this can occur on any ball.

I was in your neck of the woods the other day, spent a week walking in the gorgeous Lauterbrunnen valley!

Thanks for this HowardR, I will give these switches another clean and adjustment and let you know the result.

Thanks HowardR, it was motor switch 3B. Cleaned and adjusted it again and now it works fine. Just goes to show you may think you have cleaned and adjusted the switches, but sometimes you still need to do it again!

Finally resolved the credits issue so that the right number of credits are added according to the Jones plugs credit settings. The gapping of the score motor switches involved is very precise and they can be too closely gapped as well as having too large a gap. I guess this is all about timing, the gaps affect the timing of when the switches open and close and it is not just an issue of them opening and closing, but also when they make or break contact.

Thanks HowardR and Rolf for your help.