I have an Attack from Mars that has no sound. I am trying to trouble shoot the machine. I was going to try and trouble shoot the boards by swapping them out with my Monster Bash. Is this a good idea? and if so how do I swap them out. What chips do I need to swap on the board.

Which board should check first. The CPU board or the Audio Visual board

looks like I have some work to do tonight. thank you for all the advice. I will check back with updates.
The AV board LED does not blink if maybe after a couple minutes occasionally and the classic startup tone does not sound when I turn on the game.

I took a look at the board and could not see anything that looked like it is bad. I tried to check the voltage but unfortunately, I do not know how to do it. Here are some photos. If someone could give me some advice. Thank you. Sorry, I am still learning when it comes to the circuit boards.

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Thank you so much zaza, for the instructions! I measured and pin 7 is 11.87 and pin 5 is 5.15. I do not know what that means. What are my next steps. Thank you again.

No luck on switching the ribbon cables. The led light is supposed to blink slowly but it does not blink at all. Anything else I can try?