Galaga not recognizing joystick, no sound

irobot

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I have a Galaga PCB board set that was kind of flaky so I sent it for repair.

Now that I have it back it looks real nice on the monitor but there is no sound and it doesn't recognize any input from the coin door or control panel.

Is this a common problem? Anything I can check to make sure it's definitely the PCB boards and not the rest of the machine?

The guy who repaired the board is saying the usual stuff, check the chips to make sure they are all seated, etc.

I put in a switching power supply from arcadeshop with the galaga adapter. I tried running the game with the original power supply also. Same result either way.

The various game components are properly grounded.

Are there any kind of tests I can perform to insure that the rest of the machine is working OK?

Thanks
 
what's your definition of it being properly grounded? lol I strongly advise you run a continuity check between the logic ground on your switcher to any of the other grounds to make sure. lack of sound could very well mean that you have a lack of 12V going to the amplifier. do you have any amplifier hiss or anything coming out of the speaker?

it just sounds to me like your adapter's kind of suspect. do you have the original power supply, in a decent working condition to try out to verify if it's the switcher or your boards?

if you sent it for repair and you're just now using it, I don't entirely understand why you'd need to reseat anything on it. was the repair guy reputable? I don't do anything with these, so I don't know who to send this stuff to or whatever.
 
I have a Galaga PCB board set that was kind of flaky so I sent it for repair.

Now that I have it back it looks real nice on the monitor but there is no sound and it doesn't recognize any input from the coin door or control panel.
Were those things working prior to sending it out? Is the speaker wired in and working? Did you turn up the volume pot on the Galaga PCB?

Is this a common problem? Anything I can check to make sure it's definitely the PCB boards and not the rest of the machine?
If you have another Midway/Namco machine that's known working you could plug the board in and see if you get sound. Not sure which game harnesses are compatible with Galaga, but someone else can probably help out.
 
Which sounds are missing?

There are 2 separate sound circuits... the digital sound/music and the explosions. If both are missing then I'd check the amplifier circuitry for a bad cap or bad chip.

As for inputs, that's going to be a custom chip or a broken resistor pack or 2 near the edge connector.

Sounds like the repair wasn't fully tested before it was sent back.
 
Try reversing the edge connector, if put on backward you will have those symptoms, nothing should be damaged with the edge connector on backward.
Dick
I did this myself when I went to my Galaga board back in. It was definitely making me scratch my head and I was so glad it didn't do any damage. It seems like 9 times out of 10 you would do damage, but luckily Galaga can be forgiving.
 
that's insane. aren't some of those power pins?? I'm confused as to how the game would even come on at all that way heh

you would think they would've had a key or something in the edge connector.
 
that's insane. aren't some of those power pins?? I'm confused as to how the game would even come on at all that way heh

you would think they would've had a key or something in the edge connector.

Galaga is rather unique in that the video and power signals are connected through two AMP connectors rather than only through the edge connector. The power pins that are in the edge connector end up connecting to unused traces on the board when the edge connector is put on backwards, so it doesn't damage anything.
 
There is another connector on the board and I usually put the +5 and +12 there with alligator clips. If you look closely at the 3 prong connector one of the traces will go directly to the audio amp.


what's your definition of it being properly grounded? lol I strongly advise you run a continuity check between the logic ground on your switcher to any of the other grounds to make sure. lack of sound could very well mean that you have a lack of 12V going to the amplifier. do you have any amplifier hiss or anything coming out of the speaker?

it just sounds to me like your adapter's kind of suspect. do you have the original power supply, in a decent working condition to try out to verify if it's the switcher or your boards?

if you sent it for repair and you're just now using it, I don't entirely understand why you'd need to reseat anything on it. was the repair guy reputable? I don't do anything with these, so I don't know who to send this stuff to or whatever.
 
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