Road Kings Sound issues

[lanternau]

Hi All , Hoping someone can help....I'm a bit stuck.. My Road kings has sound issues. The Speech , Bike noises seems ok . Which would rule out the speakers. the background Music is the but is really distorted, also during the game there is no play field noise,(also the noise when collecting bonus is non existent...I noticed this one on You tube)
If I press the Sound button on the CPU I get a really, really faint oscillating noise. Bit of luck i might be able to get my hands on a Background music board, hoping the problems lies there. No noise from the CPU button concerns me a bit unless the circuitry tracks back through the Music card which may be buggered . Any assistance would be greatly appreciated....Cheers

[Boots]

What were the original sound roms like, any corrosion on the pins?
Did you replace the rom sockets?
Have you replaced the ram on the soundcard?
Run through the test sequence, that will help you determine what is working and what isn't

[lanternau]

I didn't see any corrosion ..( I had another look to be sure). I have not changed the sockets or ram. Do you suggest I do that . Does the sound card provide all sounds other that speech? Cheers

[lanternau]

One problem sorted....Sourced a replacement music board...Music and bike noises and voices is now A1. One thing it didn't fix was the background sounds. e.g sounds generated by the play field etc. Changed caps , ram,and opto's around the sound circuitry. Still the same . Any clues.....I am stumped. Maybe they are really annoying and could do with out them ,but I would like to fix it any way..  Cheers

[lanternau]

All working 100% . Turned out to be (U2) the D/A converter.Got a compatible one from RS..Works a treat.Now it makes a lot of annoying sounds........like U2