Bubba's Excavation Company

[southmonitor]

Hi:
I'm working on a Bubba's Excavation Company Game. It is frying one of the driver chips in the board; but I don't have the schematic or the wiring diagram. Does anyone is familiar with this game or know where I can find the schematic?. The chip that is frying is U109 (ULN2068B). It's a Darlington driver chip for the motors, therfore one of them is shorted or damaged and is frying the chip; but without the schematic and wiring diagram it's going to be very hard to find which one is causing the problem.
Any help is welcome.
Thanks

[lilshawn]

if you could let us know what make the monitor is, perhaps we can source a manual and schematic for it.

[southmonitor]

Sorry. I think I posted this in wrong forum. This is a ticket redemption game, there is no Monitor in this Game, it's not a video game, but I know people here deal with everything so maybe somebody can help me with this.
Thanks

[Kevin Mullins]

Well, you'll have to set a monitor on top of it before we can discuss this any further.

j/k

Does it blow any fuses ?

E-mail sent to ya.....

[lilshawn]

Well, you'll have to set a monitor on top of it before we can discuss this any further.

lol, that's do-able

[southmonitor]

Funny though...
No It's not blowing any fuses, since the power supply has short circuit protection and shuts itself off. The problem is the manufacturer does not provide the schematic; but they told me I could find it in one of this forums.

[Kevin Mullins]

Do you have a stand alone unit or a pair of them ?
I've worked on a pair of Dozers (same machine basically) and would use the working one as a comparison when first powering the machines on to see what cycled and what didn't.
Have also had trouble with the coin hopper wiring getting hacked from them pulling tokens that would cause problems. Never had that particular chip fail though.

[southmonitor]

Yes my machine is Double. The problem is that since the Power Supply is off none of the units work because is only one PS for both sides. The main board is also common for both. I unplugged the Right Hooper and the Coin and tickets counters following instructions from the manyfacturer's tech support; but the chip blew again. These parts were supposed to be the only load for that chip according to him. The problem is that everytime I do not unplug the right thing it blows the chip again. I can always trace the wires; but is going to be time consuming specially since the game is at location. I told them I was going to take the game to my warehouse to make the job easier and be able to work at times on it and not continuosly. If I can find the schematic, it will be easier to work at the game location.
Thanks

[Kevin Mullins]

Yes my machine is Double. The problem is that since the Power Supply is off none of the units work because is only one PS for both sides.

Damn, forgot you said your power supply was shutting down too, which yeah would kill both sides.
Wondering if one of the larger transistors is shorted that that chip drives or something to that affect.
I hadn't looked at one of those boards in awhile, so hard for me to recall what all was on there and how it was layed out.

[SavannahLion]

The problem is the manufacturer does not provide the schematic; but they told me I could find it in one of this forums.

Not a schematic, but I imagine this is a good start 

[southmonitor]

Thanks.

[RichSorr]

Benchmark couldn't give you schematics or atleast a manual? I haven't worked on this game in years, but might have a manual sitting around for it.

iirc this has the coin ramp that is on a motor moving side to side? does the chip blow right at power up?

I would socket the chip, get a bunch of them and start disconnecting motors until it doesnt blow.

[SavannahLion]

I would socket the chip, get a bunch of them and start disconnecting motors until it doesnt blow.

+1

Would it kill the machine to disconnect all the motors and reconnect them 1 by 1 until the chip pops? That way you lose only one chip instead of three.

[Kevin Mullins]

Benchmark couldn't give you schematics or atleast a manual? I haven't worked on this game in years, but might have a manual sitting around for it.

They have a general manual with wiring schematics, but not board schematics to tell what all that particular chip drives.

Would it kill the machine to disconnect all the motors and reconnect them 1 by 1 until the chip pops? That way you lose only one chip instead of three.

+1

And if everything is unplugged and it still blows, then the problem is on the main board itself. Been awhile since I've looked at one of those boards, but would reckon the IC drives a larger transistor for actually driving the motor involved.

[RichSorr]

Benchmark couldn't give you schematics or atleast a manual? I haven't worked on this game in years, but might have a manual sitting around for it.

They have a general manual with wiring schematics, but not board schematics to tell what all that particular chip drives.

Would it kill the machine to disconnect all the motors and reconnect them 1 by 1 until the chip pops? That way you lose only one chip instead of three.

+1

And if everything is unplugged and it still blows, then the problem is on the main board itself. Been awhile since I've looked at one of those boards, but would reckon the IC drives a larger transistor for actually driving the motor involved.

I rarely see a shorted transistor take out its controlling IC, especially more than once, but it does happen. I think the best thing to do would be check the color wires on each motor back to the connector or the board..or use the wiring diagram from the manual. follow the traces back to your blown IC and test any major components that are controlled off of that. If they test ok, pop a new IC in, start the game up with everything disconnected and start going one by one. If my memory serves me they are 24v motors? If one is shorted they will almost definitely take out your PS or cause it to cut out.

[southmonitor]

Thanks to all.
1-The IC is the final transistor Darlington stage itself. It is not driving any further power transistor stage. It drives the Motors directly.
2-The PS only gives 12V. Therefore the motors are 12V.
3- I will have to trace the wires like most of you have suggested.
4- When I replaced the chip the first time I didn't used a socket (my mistake). Therefore I will have to take it out again and solder a socket in place. I don't have a socket handy right now. I'll have to go and get one (additional problem)
5- This game is located 30 miles from my place. Therefore I have to go there only if I'm pretty sure I would be able to fix it or at least to find the problem. That's why I'm trying to locate the schematic. I don't want to go there without doing my homework first and have to come back without success.
6- I charge my customer by the hour, meaning I can't spend too much time there repairing one game. They will simply don't like it.
7- I have  to repair it soon since it's not working they are loosing money.
8- When I find what's causing the chip to blow I'll have to order that part and replace it. It takes time to get the part.
Thanks to all for your help. I'm planning to go there tomorrow anyway and start tracing wires, etc. There is no other choice here. Anyway If any one here comes accorss the schematic please let me know. I'm pretty sure I'll have other issues in the future with that game.
Thanks again to all of you.

[Kevin Mullins]

5- This game is located 30 miles from my place. Therefore I have to go there only if I'm pretty sure I would be able to fix it or at least to find the problem. That's why I'm trying to locate the schematic. I don't want to go there without doing my homework first and have to come back without success.
6- I charge my customer by the hour, meaning I can't spend too much time there repairing one game. They will simply don't like it.
7- I have  to repair it soon since it's not working they are loosing money.

Yup, I know that scenario quite well. The one place I help from time to time is about thirty miles form me, so I know the "do your homework first" situation quite well. One trip to diagnose, one trip to fix.
(hence also why I don't have a board handy to look at, it's down there in a Dozers machine)

Wonder if something is shorted BEFORE the IC then ?
Power leading to it, etc since it does shut your power supply down.

[southmonitor]

This is what I guess happened:
One of the Motors (probably the Hooper) got stuck or shorted, then it blew the chip. Remember this chip is the driver for that particular motor. When I replaced the chip, I unplugged the wrong Hooper not the one that is damaged that's why it blew the chip again. I stopped right there because I wanted to see if I could find the schematic to save some time and the chips. Since this is pretty tough (to trace the wires and find the problem) I told my customer to bring the game to my shop so I could work more relaxed. he haven't done it so I will go there again and do it right there. No choice.
This game has a buch of motors sensors and light fixtures therefore there are hundreds of wires tied alltogether. It ain't that easy; but I have to try. Maybe I find the problem in a couple of hours or so.
Thanks

[RichSorr]

sounds to me like you already know what the problem is. You know what the blown IC controls, so you know where your problem is. Just get a new chip in there and disconnect the suspected hopper. If that is not the only thing that IC controls and it still blows.  just follow the connector or use the wiring diagram in the manual.

[Kevin Mullins]

Being it's a QUAD IC it certainly has the potential to drive more than one hopper / motor / etc.

[southmonitor]

I'm not sure about what's connected there. The tech at Benchmark told me the right hooper, but I unplugged it and the chip blew, so I'm suspecting it could be the left hooper instead; but not sure.
thanks

[southmonitor]

I found the problem. Somebody put the tickects box on the right side just on top of the wire harness that goes to the right hooper short circuiting them. That was a big problem since I was disconnecting the hooper and the thing kept blowing the chip. After isolating everything I realized the problem must have been in the wire harness and bingo I found it after 5 blown chips.
Thanks to all

[Kevin Mullins]

Something like that would definitely keep you on the hunt for a little while huh?
Gotta love it when the staff is the cause to some of the problems like that.

Thanks for coming back and letting us know what you found.
 

[southmonitor]

Yeah it was pretty confusing. I mean the wire harness itself was the last thing that I thought of, I always suspected on one of the motors, hoopers or any real load to the board; but the wire harness itself?, come on it's the last thing I suspected of. It took me about 2hrs in total to figure the entire thing out. Not having the schematic was another real obstacle and working  laying on the floor with half my body inside the machine was depressing (that machine is really low). I hit my head about five times to the cabinet while moving inside the thing. LOL.
Thanks again for your dedication to my problem.