Galaga (Broken Capacitor) causing block problem ??

[BUCKETHEAD]

I purchased a GALAGA the other day.

Everything works great !

Except my Spaceship and Aliens look like blocks!

[BUCKETHEAD]

Pic 2

[Jabba]

Here is a thread I found that might help. Could be a Power supply. They mention using an ink eraser to clear the contacts...Hope this helps...

http://forum.arcadecontrols.com/index.php?topic=26389.0

[BUCKETHEAD]

Thanks!

I'll try any advice i get !

Im going to replace that old Power supply board with a new switching kit

anyway.


But i would like to solve this problem now. So i can at least play it a little in the

meantime.

Shooting blocks ain't that much fun you know ?   

[fredster]

It could be a rom problem.  It could also be a chip near the video section that's bad.

I had a board that did that and it was a Rom chip.

One piece of advice I can give you is for you to download the manual and all the manuals for the machine and look them over.  I have never read the galaga manual, but lots of those old manuals have a description of how the board works, what chip does what in a "theory of operation" section.

It might give you a clue.

There are certain things you should do to make sure it isn't a rom.  Sometimes the video problems and operational problems are due to a weak power supply.  Check the +5V on the board with a multimeter when you find out which two wires they are.  Take a probe while it's running and probe the board at the pad.  See if you are getting the voltage you need.

If you are, great.  It's something else. Look over the board and inspect it for dirt and rust.  Mikesarcade.com and ionpool.net have lots of tips for that and troubleshooting PCB's.

If you want to know more, try getting on the rgvac group (in any usenet server) and ask a few questions or search their databases.  If you look you will find an encyclopedia of information by searching for "galaga manual" or "galaga troubleshooting" in search engines.

[BUCKETHEAD]

Thanks for the great tips!

I am in luck!  the original GALAGA manual was still in the bottom of the cabinet !

I am currently trying to fold it to make it flat.

It is in a U shape.


Also i replaced the bulb in the marquee light.

And it would not light up?

Could this be a Bad Starter ?

Or do i need to toss it and buy a new one?


Thanks!

[CheffoJeffo]

www.arcadeshop.com/galaga/galaga.htm

Yes, buy a new starter (or, better, borrow one from another cab to check).

Cheers.

EDIT: Oh, and everything Fredster said ...

[BUCKETHEAD]

Yeah,  I figured it was the starter.

I will pick up a new one!

From everything i have read so far.

It looks like my problem could be the old power supply.

Or even dirty chips that need to be cleaned.

Hopefully it's one of the 2.   

[RayB]

Does that board have a test mode? That should be your first step. Mine does a RAM/ROM test on boot-up, but it's a bootleg so maybe the real thing has to be manually put into test mode first. I dunno.

Anyways, it surprises me it passes test mode and gets to gameplay with big blocks.

But as said above, check voltages too. Look for broken traces/pins. etc...

[dabone]

http://www.arcadeshop.com/galaga/galaga.htm



Clean and reseat those chips.


Later,
dabone

[Bones]

http://www.arcadeshop.com/galaga/galaga.htm

That's an awesome resource that one. Bookmarked!

[BUCKETHEAD]

I bought a Multimeter yesterday.

I have just a question?

Where do i need to put the dial to correctly test the original power supply?

First i turned the dial to 20V and the positive cord in the V mA plug and got  2.5 V

Then turned the dial to 10A and plugged the positive cord into 10A DC and got like

4.5 V

Not sure if any of these readings are correct ?

Never really used one of these things ?

Thanks any help?

 

[BUCKETHEAD]

I refered back to the tutorial on http://www.arcadeshop.com/galaga/galaga.htm

I believe i got it right this time.

The highest reading i got was 4.50 V

Is this enough juice to make it run correctly ?

Are could this be causing my problem ?

Thanks!    Bucket ...   

[RayB]

Double posting? No, you need 5.0v.

[fredster]

As far as that Marquee light, I have had two of them lately with a Bad Ballast. Not the starter, the ballast.

First, replace the starter. if that fails, take out the blub and put it back in.  If it still doesn't light, check to see that you have 110v at the AC IN.  Usually the marquees have a molex connector of some sort.  Probe that.

If you have 110v, a new starter, replace the ##@!@ bulb. If it still won't light, check the connections at the edge. One of the ones I replaced the ballast also had a real flaky connection to the light connector.  It was loose on the inside.  It had a retaining screw that must have worn down and the wires frayed over the last 23 years.

I did all that, and nothing.  I had a couple of ballasts laying around and I put it in line.  Bink. Light comes on.  Ballast was bad.

Most of the time a starter fixes it.  If that doesn't work 9 out of 10 times the bulb is bad.  But lately 2 with bad ballasts. Both midways.  One in a Wizard of Wor and the other in a MsPac.

[BUCKETHEAD]

So far i have changed the bulb and starter.

And still nothing!

Haven't checked the volts yet.

If i can't find the source of the problem?

Im just going to go to WAL - MART and purchase a $7.00 under the counter fixture.

My Galaga has a built in outlet in the bottom of the cabinet near the transformers.

I can plug it in there.  Then problem solved 

[BUCKETHEAD]

Here's a Galaga update.

Purchased a Galaga power conversion kit,

[BUCKETHEAD]

Pic #2

[RayB]

I think what you have there is the ultra-super-rare hack "Block Invaders"

[BUCKETHEAD]

Block Invaders huh?

Well i can tell you one thing.

That game sucks!


I emailed Bob Roberts and sent him the pics.

And asked him what he thought it might be?

He said this ....


It appears to be a ram problem, but I think you could have someone watch the pic while you gently press on any socketed chips to see if it pops back in... I'm thinking you might just have a loose pin on one of the soc'd chips.


Sounds good to me.

Im off to check!   

[BUCKETHEAD]

I was looking at the board and noticed it has a ( broken ceramic disk capacitor ).

The little brown round ones. The whole side of it is missing.

Could this be causing my block problem ??

[RayB]

It might.

[APFelon]

If you are having a problem with your machine, and there is a visiable problem on the board, that's the place to start.

APf

[eccs19]

If you are having a problem with your machine, and there is a visiable problem on the board, that's the place to start.

APf

Assuming that the side of the capacitor that is missing, isn't the side that has the value of the capacitor.   

[BUCKETHEAD]

I have no idea?

It says on the Capacitor that it is a 103 Z ?

There are 13 of them straight in a row.

It is C9

[JCL]

If your voltage is really 4.5v when it should be 5v, you will likely have problems.

The broken capaciter could make the problem worse, or could make a single chip be the "weak link" that fails first.

The cap (capaciter) is likely a "bypass cap". Digital chips quite often have a cap from their power pin (vcc) to the ground pin. This is used so that there is a little extra current capacity to handler transient power needs of the chip.

Digital devices quite often need extra current when they switch states, for example a ram write or read takes more current than when the chip is idle.

And the traces on a PCB act like resistors.

So in the absence of a bypass cap, extra current is pulled through the "resistor" (the PCB trace) and the voltage drops proportionatley (V=IR, Ohm's Law is your friend).

The cap between the power and ground pins provides a little extra current to keep the voltage from dropping too much.

Technical mumbo jumbo: Capacitors store charge. They will release the charge when the voltage drops and support the voltage with enough current to keep it the same. Sort of. It really requires the differential equations that model the system to really

[TheOtherBob]

103Z is a .01uF cap rated at 50v.  If you don't have one handy and want to get one quick you could always try Radio Shack.  You'll pay more but at least you'd have it quick.  You can always substitute a disc capacitor of higher voltage if a 50v part isn't available.  Sometimes size becomes an issue especially if you substitute a 500v one where there was a 50v part.  Often you could even go with a slightly lower rated one as the 50v rated one *could* be a bit overkill on the board. But I don't recommend doing that.  Try and match or go higher with the voltage rating.  The part you CAN'T substitute is the farad rating.  It has to be .01uF.

Ed at GreatPlains: http://www.greatplainselectronics.com/products.asp?cat=27

Looks like he has a .01uF at 100v for .12 a piece.

Good luck!

[BUCKETHEAD]

That capacitor was not the problem.

However i fixed 2 dead capacitors yesterday.

Still have the same problem.

I have a new set of Roms on the way.

Let's see what that does?

Thanx for all the help guys!

I'll keep you posted !