Space Invaders Cocktail Help

iamdamion

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Hey everyone! I am new to this arcade owner/restoration thing, so please go easy on me if I am calling anything by the wrong name. :) I bought a SI Midway Cocktail game and have a coin up and audio problem I just can't figure out. I searched the forums for similar problems, but didn't find anything that worked. Here's what's going on...any help would be greatly appreciated!

1. Machine wont coin up. I have cleaned all motherboard connections and EPROMs. I tested the signal to the coin up connections and they appear fine. I'm starting to wonder if it's the actual mechanism with the arm that is moved down when a quarter hits it that is fried. The counter moves, the game just doesn't register a credit. Any ideas? Anyone know where I can find more information on that part? All the manuals and instructions I could find don't have any info on it.

Note: I do have two wires that appear to have been cut near where the lock used to be n the coin door. They're near a sticker that reads "vibration switch. operates game over circuit when closed". One is solid yellow and the other is solid black. Am I right in thinking this isn't part of my coin up problem? Again, I haven't been able to find much info on what this could be.

2. No sound. I have checked the audio connection voltages at the motherboard and they are receiving power in the correct voltage range. I have tried adjusting the pot on the board, but no change. I'm not sure how to check that pot (my knowledge of electronics and boards I'd say is on the lower side of average) and my soldering skills aren't super great, so one post on here where someone said they removed it and tested it didn't seem like a great idea for me.

If anyone has any ideas I'd greatly appreciate it. I can also provide any pictures if anyone would like to see something or if I didn't explain myself well enough.

Thanks in advance!
 
Here is a good place to get some info:
http://www.brentradio.com/SpaceInvaders.htm

Here is something you might look into once you get it working(check with them first about using on a cocktail)
http://www.brasington.org/arcade/products/sim/

The vibration switch(slam/tilt switch) resets the game if someone hits the coin door really hard.
Here is a typical coin door:
Anatomy-of-a-Midway-Coin-Door.jpg
 
Thanks for the reply! I have actually been on that site, and haven't found what I need yet. Might be because I am new to this and am missing it, but I've tried everything on there I can, with no help. It helped solve other problems, but not these two.

And thanks for the link and the coin door pic. That pic pretty much confirms my thoughts that those wires went to the vibration mechanism.

At this point, I'm thinking it's the coin lever its self. Do you know of any way to test it further than what I have done (checking the voltage at the board connection)?
 
Try to get a good pic of the coin door. Does it register a credit on screen? What doesn't make sense is that the counter moves when a quarter is dropped. Those switches don't usually go bad. check the dip switches, there is a setting where it won't show credits on screen.
 
Try to get a good pic of the coin door. Does it register a credit on screen? What doesn't make sense is that the counter moves when a quarter is dropped. Those switches don't usually go bad. check the dip switches, there is a setting where it won't show credits on screen.


I checked the dip switches, and I'm attaching pictures to show it is showing zero credits (picture is still blurry...another step I'm gonna tackle later) and two pics of the coin door. I took them with my phone, hopefully they are ok.

Also, the coin counter works and goes up when I push the coin lever, just no credit.
 

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Any ideas out there? :) I'm trying to get my hands on a test rom and try to figure that out, but I've exhausted all ideas I have on this coin up problem. Since posting this originally, I've also traced the wires from the coin lever and checked all of the bundled connectors. All seems good and no wires or connections look bad.

I'm going to check the power supply soon since my readings were in range at the motherboard connections, but not dead on. I don't know if that will help anything tho.

I'm new to all of this and feel like I'm overlooking something very basic.
 
Here is another place to check out.. http://www.elektronforge.com/TestMdwPS.htm

make sure that the wires for the slam/tilt switch aren't touching anything, you might want to separate them and tape them.

You might try to email elektronforge.com and see what he might say.( be patient, they take their time with emails)

Don't give up someone may have had this problem and knows how to fix it.
 
You might not have a sound problem. Since you can't coin up you won't get any sounds. There are no attract sounds so unless you are playing a game you won't get any sound. I remember reading about this same problem with not coining up about a year ago. I'll look and see what I can find.
 
Here is another place to check out.. http://www.elektronforge.com/TestMdwPS.htm

make sure that the wires for the slam/tilt switch aren't touching anything, you might want to separate them and tape them.

You might try to email elektronforge.com and see what he might say.( be patient, they take their time with emails)

Don't give up someone may have had this problem and knows how to fix it.

Yeah, this is the page I used to test all of the connections, but I didn't test the power supply. I think I'm going to try that tonight.

As for the tilt switch, I'll tape the end of each wire up, but a quick question...any chance that circuit being broken could affect something else? I have the schematics fir this machine, bt reading them isn't my strong point.

Thanks for the help!
 
Here is the thread

http://forums.arcade-museum.com/showthread.php?t=195474&highlight=space+invaders

The coin up part starts around post 19 and as a bonus he also had a sound issue so that may be of use too.

Awesome! Thanks for the reference. I at least feel like I'm making some sort of progress even if it's research. I wasn't sure if the machine had attract sounds, so you're probably right that once I can get it to coin up I'll find the sound is fine. I'll keep digging and update. If you find any other info please send it along. Looks like tonight will be power supply testing, unless I find more when I read this old thread.

Thanks for your help!
 
The slam switch is normally open so you are not breaking any circuit. As long as the two wires aren't touching each other or anything else it's fine. Also on the actual coin switch I doubt it is bad but you can jumper the two wires briefly to see if it coins up, if it did it would be the switch.
 
The slam switch is normally open so you are not breaking any circuit. As long as the two wires aren't touching each other or anything else it's fine. Also on the actual coin switch I doubt it is bad but you can jumper the two wires briefly to see if it coins up, if it did it would be the switch.

So I just got home a bit ago and couldn't wait. I think I might have info that could get me one step closer...

First i tested my power supply according to the instructions on the Elektronforge website. All settings were close, but slightly off, so I adjusted the pots and they are now dead on. I then decided to see how that affected my readings at the motherboard connector. I followed the instructions from the same page on testing the -5, +12, and +5 voltages on the motherboard connector and all were within range. Next I tested the sound voltages as the website instructs, and it's a bit low, but the site says this only affects the amplification, so ill worry about that later once I can actually get it to coin up.

Then, I decided to try to check the coin voltages as I did with the audio. I'm not sure if this is the right thing to do, but I felt it couldn't hurt. I have the info for which wire is which from here: http://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=pinout&page=SpaceInvaders.txt

So I connected my - probe to ground, and my + to coin sw in the #3 spot. Got 5.1v. Then put my + probe at the #2 position, and was showing 115mV. I figured this might be because the switch was not flipped, so I popped some alligator clips on there are a third hand, connected them to my probes, and then flipped the coin switch. When flipped the reading went down (not up as I expected) to 102mV.

Am I on to something here? Am I now going to have to trace this brown/white wire through the whole harness and see where it has a connection problem? Shoud both of these read about 5v? Or maybe around 20 like the audio test indicates?

My lack of knowledge might be leading me down the wrong path, but my logic says that wire at #2 "coin sw" is involved somehow...

Thoughts?
 
The slam switch is normally open so you are not breaking any circuit. As long as the two wires aren't touching each other or anything else it's fine. Also on the actual coin switch I doubt it is bad but you can jumper the two wires briefly to see if it coins up, if it did it would be the switch.

Oh, forgot to add, the coin lever was making the coin counter advance. I jumpered the lever, and sure enough it advanced, but did not coin up. At least I removed that as a possibility...
 
So I tested continuity on the coin lever and it all looks good. Connecting to one coin switch connection and the ground at the motherboard connection gives a tone, connection at the other coin switch connection, no tone unless the coin lever is pressed.

I think this means I have a bigger problem? Bad ram? Motherboard needs repair? I am pretty lost on where to look. Anyone have any direction for me? I'm not skilled enough in electronics to figure out where to look by the schematics I've downloaded. Did I just step into repair territory above my skill level? :/
 
Is it moving at all or just a static picture? Try reseating the daughterboard again a couple times. Use a pink pencil eraser to clean the connector and clean off crumbs too.

The lack of invaders is either the edge connector or a board issue on the daughterboard(if its running). Not a credit issue, although could be related.

If its just a static picture that could be a board issue on either board, although wierd that it gets that far and stops it seems.

Ps coin counter will almost always work, its wired right to the switch, so even if the board doesnt recognize a credit, it will trigger the counter.
 
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Try reseating the daughterboard again a couple times. Use a pink pencil eraser to clean the connector and clean off crumbs too.

The lack of invaders is either the edge connector or a board issue on the daughterboard. Not a credit issue, although could be related.

I'm a little confused. However, since I did check all connections besides the daughterboard to motherboard it wouldn't hurt cleaning and reseating it.

However, I don't have a "lack of invaders" problem. They're on the screen and going through the demo stuff. I just can't get it to coin up/register credits so I can actually play it. I hit the coin lever, the mechanical counter registers, but the screen says 0 credits, and nothing happens when I press the player 1 or 2 buttons.
 
Ah ok...crap chances are the daughterboard will need repair then. Since the counter is registering at least that proves the switch and wiring are working. Reseating the db wont do much in that case.
 
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