(Topic ID: 147945)

Gottlieb Bonebusters MPU issue

By Jive

8 years ago



Topic Stats

  • 7 posts
  • 3 Pinsiders participating
  • Latest reply 8 years ago by Jive
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#1 8 years ago

I made a video, as it's easier to show what's going on than to explain.

The boards all look good, no hacks or battery damage. And this is what I've done so far:

All this is per the sys80 repair guide. I checked power supply voltage, right around +5.1vdc, also checked the +5v on the mpu at the capacitor near J1, and still show +5.1vdc. Unplugged all the mpu connectors except the one on the left that feeds +5v (J1?), and the display connector. It still blinks the gibberish on the displays. I've tried this with the reset board unplugged as well, and get the same result.

The relays clicking are the T and Q relays which had me thinking it was a slam switch issue, but they all look fine. Besides, if I read the article correct, I should show all zeros on the displays with only them and J1 connected.

I am thinking I may have bad ROMs, as all the labels had fallen off. I am not sure if it is healthy to have the windows exposed. I did inspect that piggyback card, and reflowed the pins...at least what I could reach.

Am I on the right track?

1 week later
#2 8 years ago

Found another MPU to swap out with, and it now boots!

#3 8 years ago

When you swapped the MPU, are you using the same ROMs from the old one? Just curious.

I'm fairly certain that exposed Windows won't erase the programming on a rom chip. You need a pretty high intensity UV bulb for that. But I could potentially see it being an issue and might corrupt them if you, say, left the board with the exposed ROM windows on your workbench under flourescent lighting for a long while.

#4 8 years ago

Yes, I used the same ROMs, so they ROMs are good.

Although it boots to attract mode, none of the coin door switches are working, so I cannot add credits, go into test, etc. The manual says the coin door switches go to A9J1. My research says A9 is the playfield, but I'm wondering where they go from there. None of that is part of the switch matrix that I can see.

#5 8 years ago

The cabinet switches go through J5 and through a 7404 chip at Z11 on the MPU, and the strobes for those switches go through Z12--it's possible that one or both chips failed. More likely Z11, though if there was a short or surge.

#6 8 years ago

Ok, I checked all the wiring from J5 to the playfield. J5 looks good connectorwise, and everything else looks good as well. I suppose I will check Z11 and Z12 next. Is there anything else that could be suspect?

1 month later
#7 8 years ago

Been awhile since I have been able to get back into Bone Busters, but I am still having the same issues being unable to add credits, or start a game. I checked Z11 and Z12 using the diode test on my meter (put positive on ground pin, and each pin should read 0.4v to 0.6v). Every other pin on Z11 was showing no reading, but Z12 was showing fine. I replaced Z11, and it reads normal now, however, it did not fix my issues. Checking further, Z13 is fine, but Z14 is showing 0.1v on pin 11, and 0.001v on pin 10 and 8. Checking Z15, pin 8 is also showing 0.001v.

It seems odd that all of these chips would have issues, but I suppose it is possible. It also occurred to me that it may not be just the coin door switches at fault, it could be the entire switch matrix. I really have no way to check to see if any of the playfield switches are working because I cannot start a game, nor can I go into the diagnostics.

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