Roadshow voltage issue?

Reddogg

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Hey all, I've got a "problem" that I'm not sure exists, but I'll throw it out there to those who know more than me. I've been having issues with my dozer blade randomly going up and down during game play, but tests 100%, and plays 100% when required. I've reflowed the solder several times, and while it has improved, the random movement still happens occasionally.

So, I decided to order the replacement opto board (product RS-BOB) from Great Lakes Modular

http://www.greatlakesmodular.com/

However, when installed, their board causes my F104 fuse to blow, which disables solenoids #1-8 (though the manual has an error that says it should disable #9-14). I repeated the blowing of the fuse 3 times over by repeatedly switching out my OEM board, and the fuse, with the RS-BOB, and every time, the RS-BOB caused F104 to blow.

I contacted Tony at GLM and he informed me that since the opto board doesn't receive 50v that the problem must be a short somewhere else, maybe in a wiring harness, that must be getting grounded by the mounting holes on the RS-BOB which are grounded, unlike the original opto board where the holes aren't grounded (which is why I don't have the fuse blowing with the OEM opto board).

Does this sound like something anyone has heard of before?

I've examined my machine and can't find anything visually that could be wrong, and the entire machine tests and functions 100% except for the occasional random raising of the dozer blade during game play.

But, could a 50v short be causing the dozer issue?

Anyways, I can always return it for a refund, Tony has been great to deal with. But, if there's an issue in my machine, then I'd rather fix the issue and keep the RS-BOB.

Any suggestions on where to look for the problem, or if any of this even makes sense?
 
Okay, I'm trying to figure this out logically before diving into the machine physically. The dozer blade opto doesn't share any voltages with the solenoids (#1-8) that are blowing a fuse (F104) on the Power Driver pcb, when the new dozer blade opto (RS-BOB) is installed.

I've got some questions to those who know more than me:

1. Does the above info.,combined with the fact that the machine tests 100%, and plays nearly 100% (the only issue is the occasional random raising and lowering of dozer blade during game play), point to a grounding issue somewhere, perhaps in a wiring harness? And perhaps that issue is precisely what is causing the random raising and lowering of the dozer blade when I use the OEM opto?

OR

2. If the dozer opto doesn't share any voltages or circuits with the solenoids that blow, am I maybe looking at a transistor, bridge rectifier, or diode issue on the Power Driver pcb itself, that is still "kind of" working, which is why the game tests and plays fine?

And last,

3. How do I determine where to begin to look for the problem when no voltages or ground lines are shared between the fuse (and subsequent solenoids) that is blowing, and the dozer opto pcb?

I'm just scratching my head on how one thing could be causing the other, when they don't appear to share anything (other than the ground, which is shared throughout the entire cabinet, just not directly between fuse/solenoids and dozer opto).

Any thoughts?

Thanks!
 
Okay, I'm narrowing down the problem, and I've tracked it to the upper right diverter (solenoid 5). I found I was getting zapped by the bracket that holds the dozer opto pcb when I touched it with my fingers. It was coming thru the bolt that attaches to a rail on the top of the playfield, which is then attached to the bracket that is holding solenoid 5. When I unhooked the harness attached to solenoid 5, and 6 flashers, the zap immediately disappeared. I then double checked it as well. So, I am getting closer to the problem, but I'm still confused.


If there's a short in either of the wires, power or ground, going to the solenoid, then why would it fire in test mode and during a game 100% of the time?


Also, when I used my multimeter on the harness going to the solenoid, the only 50v line I found was actually going to the 6 flashers in the same harness. I got no voltage when testing the pins to the solenoid itself. That has me confused, because the fuse that blows is a solenoid fuse (50v), but again the 50v line is going to the flashers? Weird.


Should I look at Q64, the transistor on the power driver pcb that corresponds to solenoid 5? But again, I have the question of why or how could the solenoid fire 100% of the time if the transistor is bad or faulty?

And last, can my coil be bad, even though it works 100%, and can that cause the voltage issue?

Thanks for any help.
 
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