Defender: worked great for a week, now dead!!!

[dazras]

Hi!  I just fufilled a childhood dream by buying a Defender machine from a guy at work.  I've had it for a week and it worked perfectly, although we didn't play for more than a few minutes each time, then would turn the machine off (we're not very good at it yet).  My kids had a snow day yesterday, and they played it with their friends for a couple hours straight.  They left it on when they were done, and about an hour later the screen was black and the buttons didn't respond.  So I'm assuming something overheated since it was the longest we've had it on.  I turned it off and back on, and the screen flashed white for a split second and went black again.  No game sounds, but I do get the click and the coin door lights come on.

I got inside and the +5V LED wasn't lit.  All fuses were ok.  I removed the 3 connectors on the PSB - no burned connections or pins.  I removed the PSB and didn't see any bad solders or burn marks.

I put the PSB back and plugged in the connector from the transformer only.  Now all 3 LEDs are on and the voltages on the 4J2 are:

1 -4.9
3 12.1
4 -14.6
5 5.6
6 5.6
12 5
13 5
14 5
15 5

I put on the 4J3 and 4J2 back on and redid the voltages:

1 -4.9
3 12
4 -14.3
5 1.6
6 1.6
12 0.9
13 0.9
14 0.9
15 0.9

And the +5V LED is out again... 
Is this a power supply issue or do I have an issue further downstream?  How do I go about troubleshooting now?

Any help is greatly appreciated!  Thanks!

[cw]

It sounds like you need to rebuild the power supply.  You can get a kit from Bob Roberts.
http://therealbobroberts.net/

You can use a meter and check the 5v line and make sure its not shorted in some place, but if it was up and running and then died then my money is on the 5v line kicking the bucket.