Did you try reseating any ribbon cables or look for blown fuses?

if your getting buzz, wondering if there's a bad ground somewhere

Are you sure the outlet you plugged into is grounded?

I know you said "all lights turn on" but is it actually booting all the way into attract mode? Are you seeing what you would expect on the DMD?

Sounds like you have something touching that should not be.

Buzzing is normal on DE games. You can change every cap and all it might do is drop the buzz 10-30% Its interference via the bsmt2000

*EDIT* WOOOPS just read your post again. Is blanking led flashing?

Any signs of battery corrosion on the board?

Sounds to me maybe your speakers or speaker is shot...Unplug the connector on the board so you can turn the game on and do further inspections.

BTW,Any signs of burn marks by the small caps on the sound board?There are 3 caps

Norma had the same problem

Check the bridge rectifier on the power supply. It might be open and half-waving. Remove the board and put your multimeter on diode/continuity test. There are four diodes inside the rectifier that all share a connection with a neighboring diode. It's possible to test this while it's installed on the board. Connect a probe to any leg and connect the other probe to a neighboring leg. Now reverse the probes. You should see a number of around 500 one way and 1 the other. If you see 1 both ways or 0 either way the rectifier is bad. Do this all around the rectifier until you come back around.

It drives me crazy when people ask for help, but haven't even checked the simple things first.

That's like me saying "Hey guys, I noticed one of my tires was low this morning! Any idea what could cause that? What should I do?"

Did you check to see if it was punctured?

Umm, no

Go check

Hey guys I found a nail in my tire. Thanks!

Not sure where this battery corrosion or bridge trouble shooting is coming from. That's news to me.

It's most likely a grounding problem as stated before.

For starters:
Look at the speaker connections and speakers
Tighten all the screws on the boards for grounding
Could also be the large filter cap on the sound board is shot and needs to be replaced (1000 mfd)

I'd start with those 3 before you start tearing into anything else.

There is no state abbreviation, that I am aware of, "NO".

If the OP was just talking about a loud buzz coming from the speakers during gameplay, sure...but he also said:

I agree more info is needed, but a bad ground isn't going to prevent you from starting up a game (assuming the machine is booting in the first place, which is probably a bad assumption).

Any chance of an update on this? Did it get fixed? I'm having the same issue on a TMNT now. It is not the DE speaker hum that is so common. It's a loud blaring/buzzing sound that's so loud you can't keep the game on.