I’m in need of some help with the sound on my Raven pin. When powered on everything comes up fine. In attract mode it make the random helicopter noise and bomb noise. During game play music and sounds work. The problem is when I credit up the machine it make a tone that starts low and progressively gets higher until it’s almost a squeel then is stops. All game play sounds are normal while it’s happening. The sound also restarts every time the ball is drained. Pressing the reset on the sound board stops it but it restarts every time the ball drains.

I have done the ground mods on the transformer under the playfield and grounded the boards to the power supply heat sink. I replaced all the fuses, several were over fused. Reflowed the pins on the power supply and replaced the trimmer pot. I redid all the molex edge connectors but not on the interconnect between the driver and control boards. I did add the 2 connectors to the end of it though. Also had an area on the solenoid driver board under the Q58 transistor that was burned badly. I ran jumper wires over the area for all effected traces and replaced Q58.

This sound issue was present before all the work I did and hasn’t changed at all. Voltage is stable and right at 5 volts coming from the power supply board. Messing with the daughter board on the the control board doesn’t change anything. Only thing that makes it stop is the reset on the sound board. I was hoping it was an edge connector issue, but no luck. I have done a lot of reading but I am lost. What do I try next? I could take a video if that would help?

I also posted on the KLOV forum. Someone there thought a bad cap somewhere or edge connector? So I tested the resistance of the connections, all good. The caps on the aux sound board tested good. Do I need to just start replacing caps on the sound board?

So I have made progress. Redid all edge connectors and interconnect cable. Replaced bridge rectifiers and filter cap and power block in bottom cabinet.

Still had sound issues. So I replaced z13 on driver board and z31 and z27 on control board. Now I have all sounds and music but only if I push reset SW2 on sound board. I read somewhere a similar problem was fixed by replacing g5 on the sound board. I tried that but no luck for me. I even replaced the sockets for the yrom and drom chips.

Some where along the way I lost my display so I replaced z1 and z2 on the display board. Got the display back.

I thought it was a reset issue since pushing sound board reset helped. So I have done the Pascal Janin reset mod with the DS1811 and replaced z2 and z3 on the control board also.

So my remaining problem is no sound until reset button is pushed. Any suggestions?