Hi everyone, first post after joining the club. I got my BK last year and man is it a blast!

The previous owner did a bang up job of cleaning it up and making it a sound game. I do however have a problem with upper targets / pop bumper not scoring and was wondering where I should ask my question (new to BK club and pinside). Do I ask here, or is there a specific thread?

Thanks in advance.

Hi guys, thanks for allowing me to ask here.

I had to replace the pop bumper ring and rod (shown here, I hope) as one of the arms had broken off and made the pop bumper non-operational. I must have hit or nicked something I suspect.

In the upper playfield, the targets drop, don't count, nor does the pop bumper score. Dropped targets get reset when the ball play is over. I've traced the column 5 wiring and tested all connections from the drop targets / pop bumper back to the main board, and all seem to check out (black / green wires).

In the switch test, with all targets up, they don't register as stuck switches, even if I manually drop the targets (I tested 29, lower right, right target) and that registers as stuck once I drop it during the switch test (which I believe is correct).

I read somewhere that changing the pop bumper may short out the main board? Is that true, or can I confirm that somehow? I've since ordered a new pop bumper assembly and hope to swap that out with the (faint) hope that this may remedy my problem, but I suspect it may be the board itself?

As per checking diodes, would one of them cause all 7 issues (6 drop targets + pop bumper)? I'm going to check that next.

Thanks.

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Hi guys, thanks for the suggestions. (sorry for the late response - likely would have been best to ask my question after the holidays when I had more time ),

I'm quite a novice here, so I just want to make sure I'm following frunch's suggestion properly. I assume when you say "disconnect the switch columns and row connectors on the driver board at connectors 2J2 and 2J3", you mean the connections as per the 2 images below? I believe that's 2J2 at the top and 2J3 underneath? I think so, but want to check.

To verify the board is working properly, I would run a jumper from, say column 5 (the GRN-BLK) to any of the row connectors, say row 3 (WHT-ORN). This would imitate the triggering of the top-left 3 bank upper target if I am reading the switch matrix properly. How do I verify that the switches respond? Do I need the pin on? Sorry for the stupid questions...

To answer Schwaggs' query, yes, all was working until I replaced the original piece of hardware. I had the machine plugged in, but not turned on (next time, unplug to be safe), so hope that isn't it.

Lastly, I've checked all the diodes as well, and they seem fine.

Thanks again!

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Thanks frunch. It appears column 5 is non-operational and I have a board problem. I got columns 1-4 to work with the switch test, but as soon as I try to get column 5, nothing.

@Schwaggs, based on this, your suggestion was to replace chip IC18, correct? Is that a simple matter?

Should I still post a pic of the switch stack of the pop bumper? If I replace the IC18, will I short it out again?

Sorry for the novice questions and really do appreciate the help.

I looked up IC18 and it appears that it's chip 6821. Is it a simple replace? I suppose it's best to get the appropriate tool, ground myself AND to unplug the machine to replace (remembering a little of my old computer chip replacement knowledge)?

Thanks all.

Thanks Schwaggs (getting closer).

In the first image, I see 2 7406's - the top one in green is 7406PC and the bottom one in red is 7406N. Which one would need replacing?

And I assume you are suggesting installing the white 16-pin socket, as per the red circle in the 2nd diagram?

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The clouds have lifted! Schwaggs & frunch - thanks a ton! I managed to replace the hex inverter 7406 and voila, she's good as new (or refurbished).

Thanks again - I never would have known what to do once I left the electrical checking behind.