road show ground short row 1

Alky

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Anyone have this error message come up on their machine??? I cannot for the life of me find the problem. I hear it may be an Ic lm339?
 
Check the Front door of your machine also...and make sure the short is not there...we actually had a Road Show a couple weeks ago with a ground short error after working fine and it was a diode on slam switch twisted. Todd
 
Well neither of these two suggestions were my problem and i still cant figure it out. I hired someone to come fix it and they gave up as well. Any more ideas people?
 
Some may have suggested, but you may have a bad chip at U20. U20 is socketed from the factory on RS, so pop in another ULN2803.

What I would do first is check all the switches on the shorted row. The switch matrix chart should be on the backside cover of the manual, or you can probably pull it off of ipdb.com. Do any switches in that row look like they have wires touching where they are not supposed to? Any diodes shorting? Do the switches look mangled in any way?

Another quick thing you can do to troubleshoot this is to pull the column and row connectors off of the CPU board. These are the green wires and the white wires. Go into switch matrix test after you unplug those, and see if the row is lit up. If it is, your prob is in the board.

Good luck,
-Mike
 
Some may have suggested, but you may have a bad chip at U20. U20 is socketed from the factory on RS, so pop in another ULN2803.

What I would do first is check all the switches on the shorted row. The switch matrix chart should be on the backside cover of the manual, or you can probably pull it off of ipdb.com. Do any switches in that row look like they have wires touching where they are not supposed to? Any diodes shorting? Do the switches look mangled in any way?

Another quick thing you can do to troubleshoot this is to pull the column and row connectors off of the CPU board. These are the green wires and the white wires. Go into switch matrix test after you unplug those, and see if the row is lit up. If it is, your prob is in the board.

Good luck,
-Mike

So I swapped out the chip, nothing. I checked all the switched, everything fine. When I take out the connectors it tells me to check fuses f114 and f115. Both of which are fine.
I see one ground wire on the coin door thats attached but when i look on the inside i see a green wire that has been cut at some point and im assuming its the same wire. Should this be going into something and if so where? Other than that do you have anymore suggestions or does it look like the board.
 
I would personally start looking for a short. Like a switch lug touching a bulb socket - something similiar.

EDIT - FWIW I just found this:
"
[FONT=Geneva, Arial, Helvetica, san-serif]WILLIAMS / BALLY PINBALL Ground Short on any row in the switch matrix
will certainly cause a serious malfunction of the game. The most common origins of
the ground short are: !. A faulty column driver on the CPU board (ULN2803 ). 2. The
Slam Switch in the coin door is mounted with two screws, which sometimes can short out the blades of the switch to ground. Disconnect the slam switch and see if the ground short disappears. 3. A faulty Opto Switch Board can also cause ground short. Disconnect the board and see if the ground short disappears. "
[/FONT]​
 
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I would personally start looking for a short. Like a switch lug touching a bulb socket - something similiar.

EDIT - FWIW I just found this:
"
[FONT=Geneva, Arial, Helvetica, san-serif]WILLIAMS / BALLY PINBALL Ground Short on any row in the switch matrix
will certainly cause a serious malfunction of the game. The most common origins of
the ground short are: !. A faulty column driver on the CPU board (ULN2803 ). 2. The
Slam Switch in the coin door is mounted with two screws, which sometimes can short out the blades of the switch to ground. Disconnect the slam switch and see if the ground short disappears. 3. A faulty Opto Switch Board can also cause ground short. Disconnect the board and see if the ground short disappears. "
[/FONT]​

Thanks gonna try now, Im going out on a limb and guessing its something in the opto board now that I read this. Ill update shortly.
 
Unplugged opto board, no success. Unplugged slam tilt, no success. Already switched chip to a new one, no success.
Now I have a headache as well.


EDIT: just an fyi no matter what i unplug i cannot get it past the start up, it either says Ground Short row 1 or check fuses f114 and f115. like i said before both fuses are fine.
 
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Man what a freaking nightmare.
"I would personally start looking for a short. Like a switch lug touching a bulb socket - something similiar."

Last stop to crazyville
 
If you unplug all connectors on the BOTTOM of the CPU EXCEPT the orange wires (these are the dedicated coin door switches), you should be able to still use the coin door buttons, regardless of the message on the DMD.

Go into tests mode, then choose "Switch Edges" with these coin door buttons. None of the blocks in the matrix should be lit... 'maybe' the one marked "always closed" will be lit, but that should be the only one. If any others are lit, you have a problem with your CPU board. If not, more than likely you have an issue in the wiring or playfield.

Trying to recall the playfield in my head (I don't have one in the shop right now). Row 1 contains these switches: Ted's Mouth, Skill shot lower, Slam Tilt, Trough jam, spinner, left sling, right ramp enter, right standup. Do any of these switches work? If you can't get anywhere with unplugging the switches from the CPU, try unplugging the coin door from the coin door interface board (inside left of the cabinet), and then power up... see if that solves the problem. Next, I'd check spinner and right ramp enter for mangled diodes caused by airballs. The diode should only be touching the white wire and the open lug of the switch in question. If it is touching anything else, there's your issue. Ted's mouth is an Eddy sensor. Try unpluging the switch from the eddy board under the playfield, see what that does.

You could try unplugging the trough optos for the trough jam opto, but you'll probably get a message on the DMD about it (like the fuse message). Make sure the diodes are soldered in the same on all switches where diodes are needed. The white wire will be soldered to the non-banded side of the diode, and the banded side will go on the unoccupied lug of the switch. The green wire should never be in touch with the diode. If just one of these is wired backwards, it could be the culprit for your ground short. I've seen this happen when someone accidentally solders the wrong stuff while putting on a new switch or target, so check those on that row.

Hope this helps.
-Mike
 
To add to the confusion... there might be 2 slam tilt switches. One is on the coin door, the other might be to the left of the cash box. Check both of these. The one in the cabinet should have a molex connector you could simply unplug.

-Mike
 
Thanks for the tips Ill be going at it later this afternoon gotta leave for a bit right now. Its my goal to have this thing working by Friday so we will see what happens.
 
No matter what i do i cannot get the game to go into any menus. When I unplug the wires at the bottom of the cpu except the coin door connector I get the "check fuses f114 f115'' message. Im starting to think the cpu board is just shot.
 
Man I feel your pain. Make sure that you put the U20 chip in correctly. When you plug it in the writing on the chip should be upside down. If that doesn't work do you have another game with the same CPU board that you can swap and test? If not and you think it's the board there are a few people that you can send it off to to get repaired. Clive at Coin Op Cauldron is one of the best. Here's Clive's email.

[email protected]
 
Man I feel your pain. Make sure that you put the U20 chip in correctly. When you plug it in the writing on the chip should be upside down. If that doesn't work do you have another game with the same CPU board that you can swap and test? If not and you think it's the board there are a few people that you can send it off to to get repaired. Clive at Coin Op Cauldron is one of the best. Here's Clive's email.

[email protected]

Yeh I dont have one to swap with unless someone can tell me if I can swap one from a fish tales with this one. I think the difference is the security chip. If all else fails thanks for the email address as this will be my next route.
 
Guido's got it. Hmmm... you should be able to get into the switch menu even with the rest of the switch matrix disconnected from the cpu. You need to disconnect any connectors from J106-J109 on the cpu, then do the switch test. If you're still getting the row short the problem is on the board. I've had the fuse error come up in numerous switch matrix errors, so I wouldn't take it literally. Even if you're still unable to get into the switch edge test with those connectors removed, you can then test the voltages coming off the board. Test each pin on J106-J109, you should get close to 12v on each. If you're getting considerably less than that on the pin controlling that row, the CPU is going to interpret that as 'switch closed'. I had a shorted row and it turned out that a bad cap on the cpu was intermittently shorting it's row to ground, resulting in a fluctuating reading on that pin.
 
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