I posted this to a very old thread last night and decided I better create a new post.

I'm having a problem with Sure Shot's bonus count: When the ball drains, you're supposed to receive 1,000 for each lit ball. But my bonus scoring is sporadic at best. I manually lit up all 15 balls and then drained it. I would get somewhere between a couple thousand and maybe 5,000. I could hear the bonus unit cycle through the three sets of five steps. But it clearly was not scoring 1,000 for each step. Several times I also heard a buzzing from underneath the playfield. I lifted up the playfield and saw the Z relay (Bonus Score Relay) was still energized.

I did what a previous pinsider described in his post: Lit up all 15 balls and then manually closed the outhole switch just briefly - enough to move the score motor 120 degrees and the spring contact in the bonus unit would move 5 positions. I did it again and it moved another 5 positions. Third time it moved another 5 positions. Then the fourth temporary closure of the switch resets the bonus unit. So the bonus unit appears to be working correctly.

But what I noticed was the Z relay energize and often would not stop. So instead of getting 1,000 X 5, it only scored 1,000 points. Sometimes it would do one quick burst, pull a second time and then continue pulling. In that case it would score 2,000 bonus. Sometimes, the coil would stop pulling and then I would close the outhole again and the same thing would happen. Sometimes the Z relay would "pulse" and I would get 2,000. Other times it would stay energized and not release and I would only score 1,000. Sometimes it would stay energized and when I temporarily closed the outhole switch again, it would stay energized through the next cycle and I wouldn't score any bonus for that cycle.

I also manually pushed in the plunger on the bonus unit and manually stepping through each contact. Every one of the 15 contacts worked - and when the Z relay functioned correctly, it would score 15,000 points (1,000 points 15 times). But often when I pushed the plunger, the Z relay would energize and stay energized. I had to manually touch the plastic armature to release it.

At first I thought the spring that releases the armature was not strong enough to pull it back into position. But I replaced the spring with another one that was slightly smaller and it didn't help. I now think that something is causing the coil to stay energized, rather than pulsing five times (for each cycle) like it is supposed to. But I'm not well versed in reading the schematic and can't figure out what is causing it to stay energized. Suggestions?

Sure Shot Schematic.pdf

Sure Shot Z Relay (resized).jpg

I checked all previous posts to see if someone else had a similar problem. Here's the post that comes closest to my situation:

https://pinside.com/pinball/forum/topic/gottlieb-sure-shot-bonus-score-problem#post-6083556

I used a lot of what Pinplayer01 did to try to diagnose my problem. But so far, no solution.

Thanks everyone for the suggestions. I did a bunch of testing and have some answers. In not particular order, here are the findings:

1. The Z Relay coil looks fine - not burnt at all. Resistance checked out at 1.5 ohms which is bit below the spec for that coil (which is 1.8). I also checked the pop bumper coil resistance and it was also a bit lower than specs (1.8 ohms vs 2.1 ohms), so it may be my multimeter is off by a bit.

2. The Add Bonus Unit Switch also appears to be fine and adjusted properly. It also appears to be working properly when the bonus unit operates.

3. There is no problem with the non-bonus 1,000 point scoring. Pop bumpers when lit score 1,000 points every time.

4. MarkG - I did what you suggested with the bulb tester. And the bulb did light each time a contact was made (with a ball that was lit). But what I found was that while the bulb was pulsing correctly, the coil seemed to be continuing to pull - even after the bulb went out. In other words, the bulb would pulse on and off the correct number of times, but the coil continued pulling continuously, rather than pulsing along with the bulb.

I say it seemed to be pulling because I could hear a hum and the armature was pulled in. Sometimes it would release (eventually); other times I had to manually touch the armature for it to pull away.

But that doesn't seem to make sense (to me). If the coil was indeed energized, then the light would stay lit, wouldn't it? When the power is off, the bulb tester is off.

As for the condition of the relay, it appears to be fine. Yes, there is a brass washer between the base of the relay coil and the relay frame. And the coil is mounted to the frame with a brass bolt.

Does this make sense to you?

Sure shot Z relay2 (resized).jpg

Yes, there does appear to be a brass washer on the top.

I'll try your paper experiment and check to see if there's some kind of mechanical reason for the armature not relaxing and will report back.

Thanks for your help!

Sure shot Z relay3 (resized).jpg

Thanks for the advice TimMe, I will check that tonight!

Chip

TimMe - you were absolutely right! There was some black gunk on the armature. It wasn't much - I couldn't even feel it when I ran my finger over it. But I used a Q-tip dipped in alcohol and it cleaned right up and now is working flawlessly. You da man! Thanks for you help!

And thanks to everyone else for your suggestions - greatly appreciated!

Z relay armature (resized).jpg

MarkG - I just gotta say, I thought this method of diagnoses was BRILLIANT! I'm gonna try to remember that next time something like this happens.

Thanks!

Chip