Help with Galaga Boards

kb0jjn

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I am new to the arcade pcbs. I have bought five of the 1981 galaga pcbs and two of the "bootleg" pcbs. All not working. I have done lots of reading and have decided to go ahead with the Galaga renue kit on the boards with the older resistor packs. I am testing blind in that I have no monitor to look at. My hope is to install the Renue kit and power up the boards to hear some kind of sound. I have used an old computer power supply and a speaker for my inital test. Some boards made some kind of sounds and others were just dead. One question that is really bugging me, When I power up the boards will there be any sounds. I think I have read somewhere there sould be a boom from the sound chip.
any help with this will be welcome.
bill
 
I suggest you build your self something with a monitor so you can see whats going on. I dont think you can go by sounds alone.
 
My thoughts the same but first I am going to put in the galaga renue kit. I just sripped one and a half of the cpu boards. I am going to need some chem wick soon. What type of video display will I need for the boards? Will just a rgb do?
I have seen boards on the web that are for going from rgb to rca and wonder if they will work.
Also I will be picking up my Heavy Barrel game on the 7th....Will that monitor work?
 
The Heavy Barrel game is my first arcade game purchase. I bought the Galaga boards to repair them. I am getting worried though. It looks like every I.C. socket I have pulled has a burn spot in the center of the board. I just hope these boards were not subjected to high voltage on the +5 line. Is there a way to test the chips while out of the board?
 
A well know problem of the galaga board (Orginal not boot leg) is that they cause this black oxidation to occur on the legs of the chips and cuase the legs to get brittle also.

The eprom can be check with know good eprom images using an eprom burner.
There are some chips that are used in other machines that you can use as a test bench.

If you fix one set of boards, use it as a test bench to repair the rest.

There are cap kits on ebay.

http://cgi.ebay.com/GALAGA-CPU-BOAR...575?pt=LH_DefaultDomain_0&hash=item53db234de7

Good luck on your repairs.
 
I just got done pulling parts off cpu board. Sockets and resistor packs and I have noticed some sort of repair on more than one of these cpu boards.
At chip located at 5b there is a resistor added to this chip connected pins 1 & 14. Also there are 2 caps added going from pins 5 & 6 to pin 7.
What is this for?
 
My friend, you picked a bad board to learn pcb repair on. Galaga boards can be a real headache to repair. Before you even start to diagnose them you need to replace sockets and resistor packs which have a high failure rate on these boards. You should be confident in your desoldering/soldering skills before doing this. If you make a mistake you will be dealing with a board with multiple problems which makes matters much worse.
Then you need a display to work on the boards. You absolutly cannot troubleshoot a board blindly.
 
I did not know how bad these boards were going to be. I am fair at soldering and have already replace all the sockets and resistor packs on one of the video boards. The cpu boards are much worse. I have stripped all sockets and cut all of the resistor packs on two of the cpu boards. Right now I am just in need of more chem-wick to clean out the holes.
I am not going to do anything more to these boards until I install the Galaga Renue kit.
I am also in need of a good power supply the one I was using, old computer supply, was only +4.85 volts on the vcc. I do appreciate the help with what does what. I understand the logic tables but do not really understand all about decoders, encoders, and timing circuits.
I can read a schematic and tell what should be active on a data line. I am having a great time with this stuff and if I get a set of boards working...Gravey.
My first computer was a Kim-1 and have been playing with electronics since.
 
I got a soft spot for this game that the reason why I have 2 galaga and several extra boards.

I am gearing up to bullet proof a series of galaga boards as soon as I finish repair a few other games. I going to use the same techniques I use when I use to do nation wide repair on computes.

Nothing makes a job easier than to have one working and one non working unit side by side and a good scope.
 
I got a deal on the 5 sets of boards and two bootleg boards. It did not look like there was too much wrong with them. Boy was I wrong. Now that I am into them I will not stop until I have a working set. It may take some time given my limited funds and testing equipment but I will get a set working. I am kind of waiting on chem wick and another renue kit right now. Soon I will have my Heavy Barrel arcade game and may use that to test with. Right now I am just testing the solder job I did on the vid. board. I have been checking point to point with an ohm meter and looking for cold solder joints and shorts. I have lots of time so I am going to be very careful. I am also looking for bent pins with the meter also.
The one board I took the photo of will wait until I have something to check against. I am kind of intrested in why the caps and resistor was added. The other board that has been worked on same chip has only one cap. and that only goes to the pin 6-7.
I am keeping a eye out for a good power supply and monitor for testing. An o-scope is a bit out of my price range but I know a tv repair guy here that my allow me to ues it for a short time.
 
You've mentioned that your 5 volts is at 4.85. Where did you apply that 5V wire to? What is your 12V reading, and where do you have that hooked up to the board? What type of speakers do you have hooked up to the board, and to what connector or pins? How many GND wires do you have running to the board, and to what pins and connectors are they attached? Lastly, do you have an edge connector connected to the board, or are you just attaching wires with alligator clips?

Pictures are good. Post some more...

Some of this might sound basic, but having a solid foundation is important. If your set up is wrong, then there might not be anything wrong with the board -- it could be your set up.

Also, I've purchased plenty of "non-working" boards that had no issues what so ever. So, did you actually see these boards not working when you purchased them, or are you just going by the description? It doesn't make sense to fix something that doesn't need fixing. And, without a display and whatnot, how do you know they aren't working, other than the missing boom on boot up?
 
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Very good questions. I have bought a 44 pin connector from mikes arcade and wired up an computer power supply.
pins A and 1 are grounded.
pins B and 2 are speaker and 8 ohm. B is the plus.
pins E and 5 are 12 volts and measure 11.6 on the meter.
pins F and 6 are 5 volts and measure 4.85 on the meter
pins G and 7 are grounded.
These are the only connctions I have put on this connector...
I will post a pic soon.
 
Yeah, definitely try and make an adapter to fit the monitor in your Heavy Barrel when you get it. I had a Crazy Kong board for years that I had no idea if it even worked. I rigged up a temporary harness kinda like you did, and got no sound in attract mode, so I assumed it was dead. I finally had a real cab for about a year before it dawned on me I could build an adapter to test it on that games monitor ;) Turns out the board I had used a different version that had no attract mode sound. Also, I don't know if it makes a difference, but most arcade games (at least from that era) use 4 ohm speakers. Another thing, I don't know if it matters whether you use one or the other or both, but besides the edge connector, Namco style boards of that era (Galaga, Mappy, Gaplus, etc) have a 3 pin auxiliary connector that also supplies GND, +5 and +12 to the board, so you might need to plug something in there. There's also a 6 pin connector for the video, rather than it being on the edge connector.
Edit: Also, I'm sure you know this, but just in case, the bootlegs probably have a different pinout than a real board.
 
I can't wait to play my Heavy Barrel game. It might be some time before I start to wire other things to it. I used to play that game all the time at a 7-11 in CA with a good friend.
One other note:
http://i1224.photobucket.com/albums/ee365/kb0jjn/DSCN1053.jpg

This is why I say that I am only FAIR at soldering. This is shorting pins 11@1e to pins 14 16 and 17 of rom at 4f.
I will really check this board over.
 
OK, that's a good start, but you're missing some grounds. Here is a pinout (from Mike's Arcade of all places!):

http://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=pinout&page=Galaga.html

You are missing ground connections on pins 'Z' and 22, and also on the 3 prong connector.

Also, I think that you need to fill out your 3 prong connector for the board to work properly. Certainly, put in the GND wire and +5V. Test after that to see if you get any sound.

Also, have you identified the volume pot on your board, and is it turned up so that if the board is producing sound, you'll hear it?
 
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