Galaga Low Voltage - Knob adjustment set to MAX

DerekICT

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My Galaga has the voltage set to the MAX (the voltage adjustment knob) and all I am getting is about 4.65-4.70 volts. Testing across the capacitor on the right board (sorry I don't know the name of the board or capacitor - the capacitor that everyone suggests you test across)

Getting horizontal white artifacts when the machine is on longer than about 15-20 minutes that get increasingly worse until the game is almost unplayable.

Is replacing the power supply the way to go or is there something else I can do?
 
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Did this ever work with the PSU you are using or are you trying to use the board for the first time.

If you are trying to get this going for the 1st time the by far the most likely issue is that you need thicker 5v and ground wires, or more runs of your wire you have. These boards are pretty thirsty and if the wire is too thin then the current draw goes up and the voltage drops down. You may also notice the connectors getting pretty warm.

Measure at the PSU and also at the board, if there is a major discrepancy then its the wire, or lack of it. Add more wire but remember to turn down your psu before you retry too or you will blast the the board.
 
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Has been working fine for about a year.

Not sure I want to start soldering... I may screw things up more than fix them :(

Appreciate your comments though very much.
 
In that case either something on the PCB is pulling more current than it used to, (so I would advise you reseat all the connectors that provide the power to the PCB, and the ribbon cable) but more likely is that it is a PSU that is getting ready to fail, or go pop. I would avoid using it with that PSU until you can swap it out.
 
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Power supply is crapping out on you, at a voltage that low you're lucky a Galaga is even booting. Get a nice strong power supply in there and crank that baby up to about 5.2 and you'll be good to go.
 
Power supply is crapping out on you, at a voltage that low you're lucky a Galaga is even booting. Get a nice strong power supply in there and crank that baby up to about 5.2 and you'll be good to go.

+1

I use a cheep switcher for the bench testing. You really want to replace or repair the supply.

You could unplug power to boards and just test voltages at the supply and they will probably be good or close to good. If you load up the supply you will probably see voltages quickly drop.
 
Your board and power supply could be fine......maybe just some shot connectors. If you're running an original linear power supply.....burnt connectors and cracked solder at the headers is common.

Edward
 
I've seen this happen when the voltage regulator on the power supply fails. If you remove the load, you can adjust it to 5v. Then as soon as you hook the board back up, the voltage falls, and even cranking it up to the maximum doesn't work. Last one I saw like this you could get it to 4.2 and not much higher. Replacing the 2N3055 fixed it.

-Ian
 
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