System 80A pinball odd behavior - power supply?

mhkohne

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My Striker recently started acting oddly - there's a couple of inputs that fire when you flip, and now it loses credits when the knocker triggers. I'm thinking it's got to be power supply, right? I've taken a DVM to it, but I'm not seeing anything - transients must be too short.

Am I looking at a component issue, or a connector issue? I haven't done too much beyond a couple of new transistors and resistors. Should I cap it as a first step?
 
Played with the connectors at all while the game is running? I JUST brought home a Sys80 game that was working fine...MPU<->Driver interconnect had a couple loose wires and there was a connector on the driver board that had a weak pin connection.
It was doing all sorts of weird stuff from not even starting to random things happening.
Recrimped them both and my game is working fine now.

Don't think that there isn't enough power in a coil to wiggle a wire in the head either. My FBC is acting up, and I've pinned it down to the Driver board needing a connector replaced...game will start if I go into coil test and hit the flippers, enough of a knock to the machine to vibrate the connector in the head!
 
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I'd bet heavily on connector issues vs. power supply (especially if you are seeing expected voltages at most times)

It's standard advice, and I know people (including me) try to avoid it because it's a PITA, but on the early GTB's, it's almost impossible to troubleshoot them effectively until you've repinned the connectors. So many different gremlins and symptoms can hide in those connectors you are just chasing your tail until you do them.
 
i'd install an extra ground on all the boards first off
screwy things can happen when its not grounded right

i wouldnt play with connectors while the game is turned on but you can take your chances
i'd repin the connectors. big job but weak pins must be crossed off the to-do list. use your DMM to see where you have a voltage drop and repin there
 
Have you done the grounding mods? Sounds to me more like a power supply or grounding issue if you lose credits when flipping. I assume the game doesn't restart or add players when you lose the credits, I figure you would mention it if it did. I had some odd behavior on a Black Hole when I first got it, fixing up the connectors and added the grounding mod took care of most of it. The sys 80's are pretty known for the ground problem, connector issues and power supply problems. If you're interested I have a sys 80 power supply rebuild kit and 'something else' I'd let you have at a great deal. I picked them up and never used them, I can dig them out and see what I actually have if you want (it's been a while so I'm a little fuzzy on what they were).

Jerry
 
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