So i recently acquired my first machine, Police Force which is the fulfillment of a teenage dream. It has a few "sometimes" problems though, like sometimes one of the drop targets doesn't register making it impossible to put drug rat in jail and subsequently no jackpot. This seems to have fixed itself though and only happened the first day i had it.

The game breaking error though is that the car will not reset. I searched this forum and found the solution was to reflow the solder on the relay boards. So i pulled the easy relay board and reflowed the solder on it. Once i put it back the car reset for one game. then after i turned the machine off it went right back to not resetting which made me sad. My friend who also has a system 11 pin (diner) suggested i unplug the machine then plug it back in. So i tried and and sure enough it fixed it until i turned the machine off again. unplugging then plugging back in seems to fix it again. When i bought the machine the previous owner told me it had an issue where about 1 in ten times you turn it on it won't properly boot up. I wonder if the problems are related.

any advice would be appreciated, i'm really new to the world of pinball repair. I can keep unplugging/plugging back in but i am afraid that if i don't fix the underlying problem it will get worse and eventually won't reset even after i unplug/plug.

ok i'll post them as soon as i get home this evening.

ok here's the mpu and powers supply

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power supply (resized).jpg

ok grumpy watching youtube on how to test it with a multimeter now. I figure i should prob get one of those lol. also here's pictures of the other boards behind the backglass.

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I checked it, it seems fine. I can manually move the car back and forth with the pulleys and theres plenty of tension on it. Its actually working fine right now. It just happens sometimes.

Ill do that for sure now that its working to get a better idea. It would be awesome if its an easy fix.

Well it stopped working again lol. So the pulley is engaging the cable but it looks like its pushing it forward instead of backwards. I read an archived thread about reflowing the solder on the relays if this happens. I did it to one of the relays im going to pull the other and reflow it.

arg. so i tightened the belt, no luck. it's definitely moving the motor forward when it should be spinning backwards. I also reflowed the solder on both relays, and also no luck. I'm not super sure where to go from here. I guess i could replace the motor but gut is telling me the motor isn't the problem. It's also having issues on startup where it seems like it's not getting enough power. it always had this issue but it's happening more frequently now. probably try to find a pro in the next few days i think.

that was next on my list. got a multimeter coming tommorrow or the next day. I suspect that might have something to do with the problems. If it's not getting the 5v do i just replace the power supply? i see i can get a rottendog one.

Thats cool i watched a video of someone rebuilding one ot didnt look too hard. I feel like its got something wrong with it bc every few times i turn the machine on it doesnt boot correctly.

I have soldered before, but never something so valuable lol. Also when looking at it today i realized that the previous owner had done a mod on the car that made it light up, but it didnt work until today, im guessing theres a short in the wire that i knocked back into life while putting the relay board back on the playfield. Could this mod be the problem? Its connected to the lights on the backglass.

arg. im out of town til sunday but i will take pictures of the car, and also where the guy wired it as soon as i get home.

this is so cool thank you guys. this thread has taught me so much. i sent completist a pm. I will happily at least pay for some gas and dinner of his choice anywhere in washington, jefferson or berkely county.

its weird the boards looked fine when i examined them with the naked eye, but was worried when all that showed up in the pics. is the driver board refering to drivers like in a computer? ie letting the hardware work with the software?

So i come home from my trip and the car started working again, but if i turn it off and back on it then doesnt work. I tested the power supply and it reads way lower than it should like .004. Its possible i'm not using the multimeter right though. I should be meeting with completeist this week tho so hopefully we can figure it out. Here are the pictures of the wiring the previous owner out in of the car mod.
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So after completist came over we decided that it was probably the belt. I tightened it after it was suggested on here but not enough. also the belt was not the OEM belt and was a bit smaller. So i ordered the actual belt for the machine and have tightened it down. I'll post pictures and stuff if that gets it working. thanks again everyone!

thought i would post an update. COmpleteist came over again and it turns out it wasn't the belt. We tried a few fixes and nothing was working so we moved to the drop target problem, one of the targets wasn't registering. After he reharnessed the wiring to the opto board the car started working fine. So we think maybe it was an issue where the drop target shared a ground with the car motor. I'm super grateful for everyones help. i was blown away by completeist's willingness to help! thanks again!

big props to completist! i learned a ton just watching him troubleshoot the machine. So far it's working perfectly. On sunday at my house there was a cookout where both my machines were played heavily. the car never malfunctioned over the coarse of probably 20+ games. the high speed completist sold me also worked great