Galaga Restoration, My First Attempt.

[tommyguard3]

Hi everyone, I've noticed people are very helpful here so I hope you can help me out.  I got a Galaga machine from my dad, he had it in his basement hasn't been working for years and he was going to toss it so naturally I took it.  Just got it to my house Monday, and pulled all the seated chips, gave them a good cleaning and reseated them.  Voila! the game came on, and works, sound is great!

The problem I'm having right now is the stars are erratic, they are usually moving very fast looking almost like lines not stars, occassionally they start to move in a choppy way, almost like a bouncing ball, and once they actually disappeared.  Also I can't be sure since it's been so long since I've played but I think the aliens are speeding up faster than normal.  I'll get pictures and video up asap, I'm trying to get the game working properly before I start on the cabinet.

Please any help would be appreciated, I'm very new to this, don't have much electronics experience, but love the challenge and learning to fix things.

Oh the other thing is my readings are low on the voltage, but that may be my multimeter, I'll borrow a friends to double check, if it is low everywhere I read says to adjust it up to about 5.2V, but nowhere says how.  Any help is appreciated.

Thanks

[beerbarrel]

There is a custom chip that controls the starfield. I don't remember its location right now but will look tomorrow. Also, their is a capacitor next the the PS connector on the mainboard. Just clip your volt meter leads across it to check the voltage. Has it been converted to a switcher?

Tracy

[Mauzy]

There is a custom chip that controls the starfield. I don't remember its location right now but will look tomorrow.

Its the 05xx on the video board, but I can't remember where. Atleast thats a little closer.   

[tommyguard3]

Thanks guys, the 05xx is at 4M, it looks like it has been replaced before, looks almost brand new.  Is there anyway of checking it other than swapping it? 

I've read through a lot of posts on the web, and someone had a similar problem with their machine, apparently it was fixed by switching the 74LS368 chip at 3N, any idea where I can get one of those?

How can I tell if it's been changed to a switcher?

Another problem I discovered yesterday that I hope someone has a simple trick to solve, but probably not, my dad lost the key to the coin door.  My door is in great shape, how can I open it?

I know I have a lot of questions, but I'm new to this.  Thanks again for all your help so far.  I'm waiting for youtube to process my video of the star field then I will post it.

[channelmaniac]

You can try to drill the lock out or to pick it. Those are your 2 choices.

Replacement cam locks are as easy as Mailbox Locks at your local Home Depot/Lowes. I like the ones at Home Depot better.

On the starfield: Check & clean the legs on the custom chips. Bad sockets will cause that problem too.

RJ

[erlsjj]

Well, my Galaga friend, you have come to the right place. I too am fairly new to this, but I have learned quite a bit over the last couple of months since I started working on my Galaga.

The first thing you should do is get the manual here: http://www.arcadedocs.com/vidmanuals/G/Galaga.pdf
It has all the schematics which are very useful. To adjust the voltage, there is a variable resistor on the power supply board (assuming you have the original linear power supply). See pg 7-4 in the manual. Turn it clockwise to crank up the voltage. I adjusted mine to 5.2V. You can tell if you have the original power supply if you have a big board on the left side of the cabinet and a big board with transformers on the floor of the cabinet. If not, then it has been replaced with a switching power supply (which is much smaller).

The problem I had with mine was a missing 07xx chip (synch generator) at 1N on the video board. I ended up ordering a replacement chip from http://fpgaarcade.com/. Not sure if they have 05xx chips, but you might check.

For the coin door, you'll have to access it from the back. The coin door lock is held on with a large nut that you can unscrew if you can get at it.

[tommyguard3]

Thank you, that is very useful information, can't wait to get home and check my voltage now that I know how to adjust it.  The site you gave me doesn't appear to carry any of the parts I'm looking for, but thanks for trying.  The manual is very helpful thanks for that, appears I have the original power supply.

Here's the video showing what the star field looks like, I just killed everyone except one alien in the first level so I could film it, not the best quality as I used my blackberry, but that is exactly what the stars look like.



I really don't think the 05xx chip is the problem it looks to be in very good shape, does anyone know a way of testing it?

[orion]

I wouldn't fuss yet with trouble shooting the board. Get the power supply in order first and then take it from there. Keep in mind I am also a noob at this, however when I got my Galaxian all it would give me was a garbled screen and bad ram/rom messages. I replaced some capacitors on the board (on Galaxian and  Pac Man the DC conversion is on the board) and it fired right up. It was a four dollar fix and if I didn't make sure the power was right at first I would have been replacing all kinds of ram and rom chips.... because the machine was telling me they were bad. Weird things happen when they aren't getting the juice they need. It very well may be something else, just make sure the power is right first and foremost.

[SirPeale]

I really don't think the 05xx chip is the problem it looks to be in very good shape, does anyone know a way of testing it?

Chips don't always burn up when they go bad.

[tommyguard3]

Okay so we have a problem...that's a good thing at least I know where to start fixing...lol.

My board is only getting between 4.5-4.6v I found three knobs that could be turned on the power supply which I'm assuming are the variable resistor you are talking about, but turning them did nothing to change the voltage.   So where do I go from here?

[Mauzy]

Wow. Im surprised you get it playable with 4.5 volts. Ive never had any luck with anything lower than 5, but I guess my board proved to be a little flaky. At any rate, keep in mind that Galaga boards were notorious for having really crummy sockets when manufacted over 20 years ago, so imagine an already iffy socket plus 26 years of use. You could have perfectly working chips and a dead board if the sockets suck.

I would recommend convertering from your current linear PS to a switcher. It may help you down the line as your current linear PS continues to age. Theres an excellent conversion kit at http://therealbobroberts.net/parts.html . Scroll all the way to the bottom. You can't miss it. You could always buy a cheap switcher off of ebay and hack the wires too, but this is an easier, safer alternative.

[tommyguard3]

how do I post pics here? looking at the picture from the website you posted I think I may have a switcher powersupply and they just left the old supply in there.  I took some pics, but don't know how to post..

What I have is right above the linear power supply is a blue box that looks very similar to what is on the bobroberts website, assuming it's a swticher how do I bump up the voltage?

[Hunk_4TH]

how do I post pics here? looking at the picture from the website you posted I think I may have a switcher powersupply and they just left the old supply in there.  I took some pics, but don't know how to post..

What I have is right above the linear power supply is a blue box that looks very similar to what is on the bobroberts website, assuming it's a swticher how do I bump up the voltage?

Hello there! To post pics try using the attachment feature after clicking on the "reply" button. Hope this helps

[tommyguard3]

SUCCESS!!!! Kind of. 

So thanks to mauzy's post I was almost positive I had a switcher ps, but in the picture on therealbobroberts clearly showed a knob for adjusting the power, I couldn't find this on mine, so I took it off and looked at it, apparently the knob had fallen off, but  with a screwdriver I was able to adjust the power up, I now have exactly 5.2V going to my board.

So I turned on the game and expected it to be working perfect...being the naive optimist that I am...lol.  And it is much improved.  now during attract mode and when I die, I get that choppy bouncing ball effect in the star field, during play, it is almost normal, but the stars look kinda like shooting stars, they all have faint streaks coming off them up and to the right.

Back to taking suggestions.

Thanks to everyone that has helped so far

[Mauzy]

I couldn't find this on mine, so I took it off and looked at it, apparently the knob had fallen off, but  with a screwdriver I was able to adjust the power up,

ha! All of mine have been like that and the knob itself always seems to be stripped. I don't know how many times Ive had to take a switcher apart to push the knob back out of its hole.

[Level42]

I know nothing about Galaga, but maybe you need this ?



http://arcadeshop.com/parts.htm

[Mauzy]

http://arcadeshop.com/parts.htm

Yeah, that would definitely be a new 05xx chip...

[tommyguard3]

that doesn't look anything like the 05xx chip on my machine.  Do I really need a new Starfield generator? I would think it is more a timing issue since the starfield is there, just moving funny.

Either way I've got a call in to a shop nearby to see if they have any in stock.  I know I asked before, but is there a way to test chips and see if they are good or not?

[Level42]

that doesn't look anything like the 05xx chip on my machine. 

It doesn't look like it because it's a new replacement built with modern-day parts.

Do I really need a new Starfield generator? I would think it is more a timing issue since the starfield is there, just moving funny.

Sorry I haven't got a clue, I just remember seeing it and thought I'd tip you about it. You could try dropping AS a line as they seem to be pretty "deep" into Galaga:
http://arcadeshop.com/galaga/galaga.htm

Either way I've got a call in to a shop nearby to see if they have any in stock.  I know I asked before, but is there a way to test chips and see if they are good or not?

The only way is using a scope and have the schematics there and know what's supposed to be going on at each pin of the chip.

[channelmaniac]

Replace the socket before you replace the chip. Galaga is NOTORIOUS for bad sockets.

[tommyguard3]

sorry to be so dense, but how do I replace the socket and where do I get one?

[Mauzy]

sorry to be so dense, but how do I replace the socket and where do I get one?

Here is what you will be looking for (not sure of the number of pins.
http://mikesarcade.com/cgi-bin/store.pl?action=search&category=IC+Sockets

I'm sure Level42 will be here momentarily to throw his 2 cents in on sockets...

To replace, you will need to carefully remove the chip that is in the socket. Then you will need to, even more carefully, remove all of the solder from the pins on the corresponding socket under the board. If you have low soldering skills, you may want to do some practicing. This will require some finesse to do. After removing all of the solder, carefully pry out the socket. If you removed the solder correctly, it should pop out easily.

Another way to do this is to try to pry off the black top of the socket which will leave a couple dozen individual pins to desolder. This method will allow for much easier removal of the pins, but removing the black plastic may be tricky.

Whatever you do, PAY ATTENTION TO TRACES! They can be easily broken and will cause all sorts of problem if broken. Just be careful and pay attention to what you're doing.   

[tommyguard3]

Thanks guys, that's what I thought, but wanted to be sure.

Minor update, picking the lock was surprisingly easy, so I have the coin door open, I will be replacing the cam lock on the door and on the rear access panel.  Thanks again for everything so far.