Low voltage on power supply

Nutty 5.0

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Game (SCI) worked fine a few weeks ago and new to having to troubleshoot these things. Only thing thats working is the marquee light. Just some quick checks on the Peter Chou power supply and the 115v side is only giving 55-60volts so 1/2. Is there something stupid I should be checking?

Thanks to anyone in advance. :(
 
Game (SCI) worked fine a few weeks ago and new to having to troubleshoot these things. Only thing thats working is the marquee light. Just some quick checks on the Peter Chou power supply and the 115v side is only giving 55-60volts so 1/2. Is there something stupid I should be checking?

Thanks to anyone in advance. :(

Yes there is.

There is a switch/jumper on most supplies, kind of like the ones on the back of your computer, they are usually for 110/220. Check that switch/jumper and hopefully it is something that simple.
 
Sadly, its set for 120 at the Chou unit. I'm wondering if something with the original wiring down at the bottom for the power supply has come loose/broken/bad connection doing the same as you mentioned. Odd that the newer 120v fl. marquee light working but there are two transformers down there. I'll keep looking and checking the schematics. Need to do more trouble shooting... :(
 
Correct Womble. Ran outta time before I could check more. The 120v service plug shows the same. Really thinking something got affected making it effectively a 220v. Only change was me putting the cabinet on its side to move out of way but doesn't mean something went loose.
 
Make sure your multimeter probes are on AC-hot and AC-neutral, not on AC and ground (like I suspect you're measuring).

If it's the latter, inspect your house wiring for proper grounding.
 
Yeah that's what I did. Should've figured that; stupid on my part. Dont know why i did that. Still will check tomorrow further.
 
This is my first time troubleshooting the machine. After confirming I have proper voltages in and out of power supply, is there a next step of troubleshooting? Do the switching power supplies fail regularly?

The machine as stated turns on the marquee light and get the sound from the monitor (nothing else)but the game isn't playing blind so pretty sure there's a power issue to board at minimum.
 
This is my first time troubleshooting the machine. After confirming I have proper voltages in and out of power supply, is there a next step of troubleshooting? Do the switching power supplies fail regularly?
No prob, everybody has to start somewhere. Yes they can fail, but you just said that you measured good voltage in and out of the power supply. That proves your power supply is working.

The machine as stated turns on the marquee light and get the sound from the monitor (nothing else)but the game isn't playing blind so pretty sure there's a power issue to board at minimum.
Ok, you've proven that the power supply is working but it's still possible that power isn't getting all the way to the board. You could still have a broken wire, unplugged connector, etc between the power supply and the board.

Take another power measurement right at the PCB edge connector, or even better right on the PCB. If you see 5v/12v then you know your theory is untrue because power is getting to the board. If you see 0v then work your way backwards until you find the point where the power stops flowing -- a broken wire, unplugged connector, etc.

Always use a scientific method when trying to diagnose a problem:
1) Come up with a theory (like "power isn't getting to the board")
2) Take a measurement that proves whether or not your theory was correct (measure voltage at the power supply, at the PCB)
3) Adjust your theory according to what you just observed (like "saw voltage at the power supply but not at the PCB, so there must be a problem between the powersupply and the PCB")
 
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