Galaga PCB advice needed, part deux

irobot

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At this point the game reboots a lot when it's first turned on and occassionally at random times thereafter.

Aside from that it works fine.

I put in a switching power supply and it is adjusted to read 5.2 volts exactly, measured at some capacitor on the PCB per the directions from arcadeshop.

Any pointers or insight would be greatly appreciated.
 
Have you already tried to figure out what the problem is? Or sent the board to someone who can? I would personally advocate that route, instead of brute force replacing components. I haven't worked on a Galaga yet, but these games are not all that complicated .. so with some help from around here they can be fixed in a methodical way.

That being said, I would start by verifying the power at various points across the board, and the source of reset (likely the CPU is going off into the weeds and the watchdog is resetting it). Are there any clues on-screen before it resets? What are the results from the self-test?

LeChuck
 
I haven't worked on a Galaga yet, but these games are not all that complicated .. so with some help from around here they can be fixed in a methodical way.

The methodical way is to replace the horrible resistor packs. And, most likely, the sockets too.

The resistor packs on Galaga are these horrible "printed" things that fail open. The pins detach from the substrate, or they corrode slightly. They are fragile and easily damaged. They're on a lot of the address lines, and without them the game crashes and resets, won't boot, etc. Troubleshooting a Galaga board without replacing them is like trying to bail out a sinking boat with a spork.

Even if you do go through and test them all, there's no guarantee that they'll work after they've been bent, touched, or looked at. You're far better off replacing them first, then troubleshooting from there.

The sockets are a real problem too. They're single wipe, and are very sensitive to heat, corrosion, and tiny amounts of board flexing. I've seen several boards where the original sockets were fine. And I've seen plenty of bad ones. It takes about as long to test the sockets as it does to replace them, and you'll be a lot better off in the long run with the new sockets.

-Ian
 
Have you already tried to figure out what the problem is? Or sent the board to someone who can? I would personally advocate that route, instead of brute force replacing components. I haven't worked on a Galaga yet, but these games are not all that complicated .. so with some help from around here they can be fixed in a methodical way.

That being said, I would start by verifying the power at various points across the board, and the source of reset (likely the CPU is going off into the weeds and the watchdog is resetting it). Are there any clues on-screen before it resets? What are the results from the self-test?

LeChuck

I'm going to do all the common housekeeping type upgrades, a lot of these games have weak spots, might as well fix them up and bulletproof the thing a little .

The edge connector is really rank looking, why not replace it?

Same with installing a switcher power supply, everyone knows that the original power supply is weak.

Let's put it this way, my wide screen TV barely worked, constantly went black, until I just replaced the $0.25 factory HMDI cable with a $15 non-POS. Now it works perfect.

TO ANYONE WHO IS READING THIS - BE AWARE THAT YOU CAN PUT THE EDGE CONNECTOR ON BACKWARDS AND THE GAME WILL RUN WITH NO SOUND. YES, IT IS STRANGE.
 
The methodical way is to replace the horrible resistor packs. And, most likely, the sockets too.

The resistor packs on Galaga are these horrible "printed" things that fail open. The pins detach from the substrate, or they corrode slightly. They are fragile and easily damaged. They're on a lot of the address lines, and without them the game crashes and resets, won't boot, etc. Troubleshooting a Galaga board without replacing them is like trying to bail out a sinking boat with a spork.

Even if you do go through and test them all, there's no guarantee that they'll work after they've been bent, touched, or looked at. You're far better off replacing them first, then troubleshooting from there.

The sockets are a real problem too. They're single wipe, and are very sensitive to heat, corrosion, and tiny amounts of board flexing. I've seen several boards where the original sockets were fine. And I've seen plenty of bad ones. It takes about as long to test the sockets as it does to replace them, and you'll be a lot better off in the long run with the new sockets.

-Ian


+1

You get it fixed only to find that slightly moving a crappy resistor pack will put you right back to where you are at now, trying to fix it...AGAIN :(

Spend the 18 +/- Dollars and get it fixed once and right.
 
I agree these are all common points of failures, and when bulletproofing a board they should probably be replaced/upgraded. When debugging a board issue though, I personally believe in finding the actual root cause instead of changing multiple things at once and seeing what happens (possibly masking the issue in the process).

The brute force approach works for lots of people, and in some cases gets the game working again faster; but I place more value on a methodical approach and root cause.

Just my two cents ..

LeChuck
 
the galaga renew kit seems crazy...just a crazy amount of work full of peril at every turn.

now I'm really not a fan of 60-in-1s as most of the games I've played on it are nowhere near their arcade counterparts, but Galaga does seem to be the one game on there that's virtually identical...would I be crazy just to put my mostly working galaga board on the shelf, get a galaga to jamma converter and put in a 60 in 1 that boots directly to galaga?
 
the galaga renew kit seems crazy...just a crazy amount of work full of peril at every turn.

now I'm really not a fan of 60-in-1s as most of the games I've played on it are nowhere near their arcade counterparts, but Galaga does seem to be the one game on there that's virtually identical...would I be crazy just to put my mostly working galaga board on the shelf, get a galaga to jamma converter and put in a 60 in 1 that boots directly to galaga?

Yes it does... but it's the only way in my opinion to get a stable board. There are too many crappy sockets and intermittent resistor packs on those boards.

Now you see why I charge $90 to repair a Galaga board.
 
Gallaga board. How to fix them the slow and painful way.

Buy the resister kit and the audio cap kit.
Buy the sockets at least the dual wipe socket or the machine sockets.
Buy flux. Yes I know you have flux in the solder. Buy More flux.
If your keeping the old power supply buy caps for it and the Bigger Diodes if they are burning.
Gold plated pins for the power supply.
a temperature controlled soldering iron. To prevent the board from burning and possibility of lifting of traces.
A good electronic solder sucker.

So your galaga is acting up and you want to built proof it.

Test the power supply.
See if your voltages are correct.
Replace a caps one at a time and replace it with the correct value cap.
Removing all the caps at once might give an opportunity of putting the wrong cap in the wrong place.
Test Power supply.
If you have burning diodes issue. Replacing them with a bigger value that can handle the heat issues.
Test power supply.
Look at the power pins are they corroded? Replace them with Gold plated version.
Get the gold plated pins for the power section.
Wire by wire pin by pin replace the pins in the cable.

You should have nice stable power.
If not you need to trouble shoot the reason why it is not.

Clean and or repair the edge connectors if need be. This will minimize the the oxidization resistance. If your lucky a Simple pink erases will wipe off the Oxidation crud. If not you might need to replace the edge connector or repair it.

Check the game.

Now you should be getting Nice clean and stable power.

Now on to the board.
Get a magnified lamp and do a slow and and careful look at the board.
Even tho there is Dust and crud on the board. Don't go running to wash it. You might cause more problems by washing it.
Look at the printed resistor pack. Do Not move them or bend them. You looking for something that doesn't look right. A pin sticking up or cracks. If you see more then one, Make a note of where it is at on the board position.
Replace the worse looking one. Flux the holes and the pins of the new resister packs to prevent bridging .Test the board. Repeat until you replace all of the resistor packs.

If your lucky the the board should be more stable. It should not be worse.

Start to replace sockets. One IC at a time. This is were a good electronic solder sucker Will shine.
You don't want to over heat your board. Take your time. if you have to use solder braid make sure it not the cheap stuff. Cheap stuff will transfer need more heat and you might lift off a trace. Once one chip is replace. Test the board.
Keep replace sockets one at a time with testing in between. Remember to use flux.
After your done.

You should have a stable board.
Replace the caps on the board.

It should have a very stable but dirt board.

Wash the board after I wash I use a Demineralized water and isopropyl alcohol pcb cleaner to speed up the drying time. Use air to blow away any moisture under the chips. If you are going to dry it in the sun. Cover the windows of the eproms. You don't want to risk of accidentally erasing any information in your eproms.

There are many things that can go wrong when fixing this kind of board.
Sometime it is just more simple to send out your board and replace the power supply with a switcher.

if you enjoy repairing than repair away. If you think repairing it by yourself is a way to save money. You got to figure out what is your time worth? For most people it will take them 2 days to repair a galaga. Is two days of your life really worth saving 90 dollars?
 
...This is were a good electronic solder sucker Will shine...

YES YES AND YES!

With my Pace unit I put the iron on the joint, count to four then hit the button. I transfer enough heat to pull the solder out that likes to sit under the socket pin between it and the board. This is what causes the traces to pull up when you remove the socket.

Doing it this way allows me to lift the socket right off the board with no issues.

...You don't want to over heat your board. Take your time. if you have to use solder braid make sure it not the cheap stuff. Cheap stuff will transfer need more heat and you might lift off a trace.

Heat is your friend AND your enemy. Traces are held down with some funky industrial epoxy and too much heat will lift the trace right up. You need enough to get all the solder out from under the socket pins but not so much you lift traces.

Also, one of the things to do is to clean the legs on the custom chips. I've tried a bunch of different methods but the problems of breaking pins are always an issue. THE way to clean them without breaking pins (sanding, erasers, etc... will break pins) is to use Q-Tips and Tarn-X.

You can get Tarn-X at any Walgreen's (and probably CVS too...) but it stinks like rotten egg farts. Use the Q-Tips and Tarn-X to clean the inside and outside surfaces of the legs. Just keep gently wiping and the pins will look almost new when done. Rinse the chips with water and let dry.

I've started using this method recently and have had great results.

RJ
 
With my Pace

Ten plus years ago. I tested about everyone's Desoldering tool. Pace was the best. Not only working out of the box but still working 2 years after the fact. The others seem to get jammed after a few months of heavy use.

Doing it this way allows me to lift the socket right off the board with no issues.

Most other methods one needs a little wiggling to break the the legs free. I have found that just a Little circular motion will the pace and everything comes out cleanly.

Traces are held down with some funky industrial epoxy
That funky industrial epoxy was available at one time but Because of the new rules and regulations it not easy to obtain. There are some new Polymer Adhesive that activates with heat. One of those new things to try when I have spare time.. Laughs.

use Q-Tips and Tarn-X.

Thiourea 000062-56-6 5-7
Sulfamic acid 005329-14-6 3-5
Hydroxyacetic acid 000079-14-1 <1
Citric acid 000077-92-9 <1
Detergent/Inhibitor mixture 000000-34-8 <1

Is what in Tarn-X. Cleaning the legs afterwards using Tarn-x is important. You don't want this brew sitting on fragile IC legs for a long period of time.

Remember never use a Microwave to Dry your IC chips or PCB boards.
 
The instructions say to rinse well with water. :D

Sure does a great job on the chip legs!

Speaking of Galaga... finished up a bitch of a rebuild on a parts board tonight.

http://newlifegames.net/nlg/index.php?topic=153.msg142215#msg142215

It was an interesting board to try and track down the problem on. It would fail with a RAM error... 4L most of the time but also 3L, 3H, and 2L. Touching various pins on chips would let it finish booting... but that turned out to be my wrist resting on the board instead of the logic probe pin touching a chip pin.

Looked at the 74LS138 with the rusted legs... typical TI chip... If I put the logic probe (with my finger on the tip of it too for extra capacitance) on pin 5 it would boot every time I reset it. Replaced the chip and it's playing nicely.

RJ
 
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