Hey guys! I'm a new addition to your Pinside crew. I'll have to get around to putting my background together here soon, but the short of it is that I just recently bought my first pin, Dungeons and Dragons, and I've also inherited the MIBS machine that is bordering on a family heirloom.

D&D has been running decent for me (just received it two weeks ago), but started with an infrequent kickout of a second ball. It is starting to act up a bit more, and will now sometimes try to kick out a ball several times in a row, then give an error to check FU1 fuse.

I've been doing research here and other sites, and I do have a background doing minor troubleshooting of different automated machines, so it seemed logical to assume the machine is not registering that a ball is being kicked out. Glancing into the mechanism I noted several optical sensors, so I tried cleaning them with IPA, but still the extra balls kick out.

Here's the other steps I've done:
1) Using the on-board diagnostics, the machine indicates that the last switch in the trough before the shooter lane is closed, even with all balls ejected.

2) From reading several good posts here on opto boards, I get out the ol' video camera with the night vision, unmount the board, and I can see that LED4 is not emitting (correlating to the switch from the diagnostics.) It is also apparent that CP1 on the board is missing, with part of a lead still protruding from a hole - my guess is an attempt to correct the failed emitter.

3) I also remove both boards when powered to cause of of the other LEDs to shine on LED4's corresponding sensor and the "stuck closed" switch diagnostic goes away, meaning I should only have a problem on the emitter side.

At this point I assume that LED4 needs to be replaced, and I see the part is a Motorola MLED930, out of production. Someone is selling some on Ebay for about $5 a piece, with another $6 in shipping - at that point I'd just as soon spring the $50 for a new set of boards.

Here are my questions:

1) Does anyone know of a good direct replacement for this part that is readily available? I've found several ir-LEDs on Mouser.com for example that also emit at the 940 nm, but I am really not that experienced with sifting through all the attributes of a component datasheet and knowing all the values to match. What happens if I choose an emitter with much greater intensity - does this cause problems?

2) What are the repercussions of not reinstalling CP1? I can easily find another 10mF tantalum cap - what voltage rating should it have? Is doubling the voltage rating on the cap the way to go (i.e. use 10v rating?) I don't know what exact part was originally here, just a Bally part number.

3) Lastly, any ideas as to why the problem is intermittent, even though the emitter seems completely dead? I'm confused why the game is not continually trying to eject every ball all of the time if it thinks this sensor is always blocked. Maybe it isn't looking for a state change at that sensor all of the time, and seeing a change in the preceding sensors is adequate?

Thanks for any help you can give! I have only been lurking for a short time, but this community seems terrific. I hope I can return the favor in the future, and get to know you guys (and gals) better!

Zim

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I appreciate your input, it makes sense to just get the new boards, but I suppose I can chalk it up to being new to the hobby and trying to get some notches on my belt, building my confidence to tackle some big job in the future. Thank you for the reply!