When you said the connectors look OK did you pull the boards off and look at the header pin solder joints for cracking? Almost every old game has cracked joints. Fix those first. And double check continuity between the wiring for the speaker and volume pot to eliminate them

Next take a look at the sockets for the proms, if they are scanbe sockets they need replaced. And if the legs are black or tarnished the proms will need replaced as well.

The sound board gets AC power in the upper right connector, goes through the 2 fuses, through the bridge rectifier to make +12v and -12v, and then +12v is regulated by a 7805 to make the +5v. Check all of those to make sure you have the correct power available on the board.

After that there is a whole bunch more to investigate, but I'll let the pros take over. Pinwiki has a bunch of information about the type 1 and 2 sound boards.

Look at some of hhasse threads... Has a video too of where to start... But first step is always press test switch on sound board after u make sure all connectors are pushed in... Push those ROMS in too to make sure they are seated.

Check volume control knob. Crank it all the way up. If you get hum you know speaker is getting power.

Beyond that, you've received pretty much the basic troubleshooting advice.

Check fuses on sound board (4 amp slo blow)
Check and reseat connectors
Check and reseat socketed chips
Use the test button to see if you get sound

Depending upon the results from these steps determines what's next (sound boards, driver board, something in between.)

Gorgar is 35 years old. His guts are old and brittle and he doesn't take kindly to being moved about...

viperrwk

As others have noted, connectors and sockets are the two prime suspects.
Here's more info...
http://www.pinwiki.com/wiki/index.php?title=Williams_System_3_-_7#Sound_.2F_Speech_Board_Issues
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Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info

Always make sure you start with a speaker you know that works, then troubleshoot.

The sound connection is a small 2 wire connector. I only mention this because both times I moved my Gorgar, I forgot to plug it back in. The wire always seemed to get lost inside the cab during the move

Any update on this? What was your issue? Im going to be trying to diagnose a gorgar that suddenly stopped having sound.

I had the same issue a year or two ago, reflowing the joints did the trick, still working today.

On mine, I eventually put in a different sound rom in..and no issues since

Updating my issue. I had a guy walk me through over the phone some test points with a multimeter on the sound board. It appeared my negative line wasnt giving a proper reading. The tests lead my friend to believe the bridge rectifier was bad. I got a replacement mda200 and put it on the board. I also reflowed all the headers for good measure. GORGAR! SPEAKS! AGAIN!