Gallag help needed

VIPER13

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I don't know if anyone out there is familiar w/Gallag or not, but I have had this game for quite a few years now. I was playing it a couple of weeks ago and it started acting up. First the score would start rapidly increasing, than it started to freeze up and I would get a RAM error in the bottom right corner of the screen. Now, I power it up and I get no picture or sound, just a blank white screen. I tried pulling what chips I could get off the board and made sure that I cleaned them really good before placing them back. Still nothing. Does anyone know what the problem may be? Is there anyway to test the board or find out what RAM chip could possibly be bad? Could it be the power supply? I put a new one in a couple of years back and haven't had any problem up until now. I planned on taking the board out of the cabinet it is in now (Original Taito Zarzon) and putting it in a Galaga cabinet, but now I may just sell the whole thing or try to trade it.
 
I don't know if anyone out there is familiar w/Gallag or not, but I have had this game for quite a few years now. I was playing it a couple of weeks ago and it started acting up. First the score would start rapidly increasing, than it started to freeze up and I would get a RAM error in the bottom right corner of the screen. Now, I power it up and I get no picture or sound, just a blank white screen. I tried pulling what chips I could get off the board and made sure that I cleaned them really good before placing them back. Still nothing. Does anyone know what the problem may be? Is there anyway to test the board or find out what RAM chip could possibly be bad? Could it be the power supply? I put a new one in a couple of years back and haven't had any problem up until now. I planned on taking the board out of the cabinet it is in now (Original Taito Zarzon) and putting it in a Galaga cabinet, but now I may just sell the whole thing or try to trade it.

I have a Gallag hooked up in a Galaga cabinet... I know that when Pacs don't get their +7.5VAC (+5VDC) they show up with a white screen. Might be the same problem. Check voltages... in the mean timeI can start playing with the power on my boards and see if I can get it to show just a white screen by turning the voltage down? It's already pulled away from the wall because I was fixing the marquee lights, so it wouldn't be a problem.

EDIT: Just looked at my spare board, there are 6 2114 ram on the blue board, and 2 2114 ram on the green big board. Wouldn't be that hard to take them off and replace them with known good ram. Putting in sockets for everything you remove and replace, of course.
 
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How do I go about checking the voltage? I tried turning the knob on the power supply while the game is on, but didn't see any change. If the power supply turns out good, can I just replace the RAM without replacing the sockets that they go into? Is it worth keeping this board if I can fix it and investing in an original Galaga cabinet to put it in?
 
How do I go about checking the voltage? I tried turning the knob on the power supply while the game is on, but didn't see any change. If the power supply turns out good, can I just replace the RAM without replacing the sockets that they go into? Is it worth keeping this board if I can fix it and investing in an original Galaga cabinet to put it in?

I bought my Gallag boards because I needed a break from try'ng to fix my Galaga boards.

To check the voltage, you'll need a multimeter (you can get them at radioshack for cheap). Then you'll have to measure the voltage at certain pins on the EPROMs. Put the black lead on... crap, I can never remember which pins they are. lol I'm sure someone will chime in on that.

Then you adjust the voltage to where you read 5 volts on the chips, a little extra won't hurt.. so lets call it 5.1 volts, not much more than that though.

For the RAM (the 2114's), if you're lucky enough that they're already socketed on your board, then it's easy to swap them out. They aren't socketed on either of my boardsets. I just socket EVERYTHING (minus resistors and capacitors and stuff like that) when I remove them because if they've failed once, they could fail again and it's so much easier taking something out of a socket than it is desoldering it from the board.

If it's not worth your time to fix it, just sell it to someone that will take it, and buy a new Gallag board if you want. They're on eBay all the time, I think there's one on there now, working, for like $25.
 
I never tested the voltage when I put my new power supply in. If the voltage was too high could that have caused the RAM or ROM chips to burn out? Will it fry all of them or just some? I put the power supply in a couple of years back, but only used the game about on occasion since.
 
I never tested the voltage when I put my new power supply in. If the voltage was too high could that have caused the RAM or ROM chips to burn out? Will it fry all of them or just some? I put the power supply in a couple of years back, but only used the game about on occasion since.
I have owned several Gallag boards over the years and as a whole they are more reliable than their Midway brothren. However, they are very picky on voltage and all need either 5.1 or 5.2 volts (exactly). If the switcher voltage is drifting, then that may be the cause.

Check the voltage at the edge connector or on the far side of the PCB.

Scott C.
 
I am kind of new to the technical aspects of the machine. Can you explain the edge connector better. Is this where the main connection is to the board? If so, at which point should I test it?
 
Assuming you have the same Gallag boards that I do, this will show you where to put the leads to test.

Red lead goes on the redder area (right)
Black lead goes on the darker area (left)


With the machine turned on, measure there to see if your near +5V. DC.. The meter has to be set on DC.

If you're low, hold the meters on those points with one hand, and turn up the voltage a little with your other hand until you get it @ 5.1VDC or so. If your voltage is too high >5.2VDC, then same deal... but in reverse... turn it down a little till you're about 5.1V.

Once you get the voltage there, turn the machine off, then back on after a few seconds. If you still have a white screen then there could be bigger issues. If you're getting no voltage, then... we'll go from there.
 

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Thanks everyone for the help, I will let you know what I find out.
 
Ok, I checked out the voltage at the board and it is set for 5.13V. Still a white screen though. Where do I go from here?
 
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Did you ever get this resolved? It's been a while since I looked at a Gallag, but seems like there is a brown wire coming from the small aux PCB that has to be connected or it does something like this.

Scott C.
 
I doubt that it's associated with your problems, as I never had any of the other symptoms, but I also had a white screen problem with mine while dealing with an atrociously bad video wire harness. After re-seating the video connectors a few times the problem eventually went away.

But when you get the white screen on power-up, are you still getting the rolling explosion audio? Or does it hang up on a high pitched tone?
 
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