So in the middle of playing a game, the sword lock quit releasing balls and I got a tech alert saying to check the sword lock coil.
I powered the game down, checked the coil for a short, it was fine. Doesn't look burnt, no smell.
Checked the fuses, F7 was blown.
Replaced the fuse (5a slow blow) turned the game on, worked for a couple minutes, fuse blew again.
Replaced fuse, turned game on, blew immediately.
I can get the coil to fire by jumping the transistor to ground so the coil seems fine.
The entire +20v circuit is out and I am thinking possibly the bridge rectifier (B2) died.
Is there a way to test this without pulling the board?
Any other suggestions on what the culprit may be?
Thanks in advance for any assistance!

Thank you for the awesome write up and diagram!
Will go through step by step and report back.

Pin_Guy

Results below:

2) Use your ohm measure the following:
With the RED lead on ground, place the black lead on J17-6 and J17-7 both points should measure around 2M ohms
MEASURED 1.8m and 1.7m
With the BLACK lead on ground, place the red lead on J17-6 and J17-7 both points should measure open.
MEASURED 9.7m and 9.7m
With the RED lead on J7-1, place the black lead on J17-6 and J17-7 both points should measure open
MEASURED 9.5m and 9.1m
With the BLACK lead on J7-1, place the red lead on J17-6 and J17-7 both points should measure around 2M ohms.
MEASURED 1.5m and 1.9m

Going to try the next step now
If I turn the game on with J6&J7 unplugged and the fuse doesn't blow, is it OK to plug them in one at a time with the game on to see which one causes it to blow?

Pretty sure I just found the problem.
The Destroy The Ring flasher socket has a loose connection.
I pulled the bulb out, which releases the spring pressure and sandwiches the connector, and everything is working fine now.
Played 3 games, no issues.
Tested the socket, no short.
Going to repair/replace the socket and see if the fuse blows again.
Thanks everyone for all the great advice!

Thanks for the assist, I will post a pic of the flakey socket when I get back home. I'm sure others will have this issue at some point.