My 8-Ball Deluxe drop targets are acting funny, it initially started with the 6 ball drop target not registering unless it was hit first. So I de-soldered every diode on the drop target switches and tested them all. It was my first time checking diodes with a multi-meter but they all didn't register in one direction and showed a number around 800 in the other direction.

I don't quite understand the schematics but it looks like there are more than just the drop targets on the same switch matrix? What other kind of things can I check? Is there a possibility this could be a board problem? Thanks for any help you can provide.

Hi,

Thank you for the reply. In switch test mode the target registers but I'll test with a multimeter. I'll try to figure out number 2 - basically when I short the row and col on the board based on the schematics the drop target I'm shorting should register? And if it doesn't what does that mean? Thanks for the help.

I guess I have the wrong diode on one of my target switches, it is a IN4004 instead of an IN4148, would that cause a problem?

Looking at this diagram, I have to disconnect J2 from the A4 board? What is the other harness I have to disconnect?

This is a good explanation of what I am doing?

http://www.pinwiki.com/wiki/index.php?title=General#The_Switch_Matrix

And this is what I have to do?

http://www.pinwiki.com/wiki/index.php?title=File:Sys11_switch_matrix_test_col.jpg

Thanks.

I've done most of that. The switches work fine. In switch test mode they all register fine. It is just the order in which the targets are hit that matters. Hitting one of the problem targets first it always registers, hit another target first and it doesn't register. I'm going to do the troubleshooting Markmon suggested above on Friday and see if I can figure out what is going on. Thanks for the replies.

If anyone happens to read this thread and could offer some more advice. I jumped all my strobe lines with all the rows on my MPU board and everything tested fine. Starting with column 1 (Strobe 0) and going down all rows the switches all worked and registered in order from 1 to 40 something.

So I guess the problem is under the playfield? Any ideas on what to look for next? If I want to test other diodes/switch issues is it likely to be on the same row or same strobe line as my trouble target? I was doing some more testing today, if I hit the 1 target first it registers and then if I hit the 6 target it doesn't register BUT if I lift the 1 target back up (open the switch) the 6 target immediately registers - right as the 1 target switch opens. Does this sound like a diode issue?

Thanks for any help anyone can provide.

Here's the switch matrix.

Screen_Shot_2012-04-28_at_2.35.32_PM.png

I did test all the diodes on the drop targets and they were fine. It isn't just an issue related to the 1 target, it is all the targets 1-5. So if I hit 1 or 2 or 3 or 4 or 5 first then the 6 will not register. If I hit the 7 first and then the 6, the 6 will register. If I hit the 7, then the 1 or 2 or 3 or 4 or 5 target the 6 will not register when hit. If the 1 or 2 or 3 or 4 or 5 are down the 6 will not register. It will register once I open the target above the 6. For some reason the 7 target does not do this. I'm about to try the shotgun approach and start replacing all diodes.

I'm still working on it. I replaced all the diodes on the drop targets. Behind the drop targets are the stationary targets which have a capacitor and a diode. I've been told it is more likely a capacitor issue, so I've started clipping those off on any switch in the same row/column. Although I was reading some Clay's literature last night where he mentioned something about drawing a box around the problem switch on the switch matrix and any of those switches could be the culprit. I'll post back if I find a fix.