Hello, I'm not an expert in electronics but I do like to learn what I can.

I have a world cup pinball that worked fine, unfortunately now I have a problem with the sound.

When turning on the game I get no bong, I sometimes get sound error or sound interface error.

After around five minutes of the game being on I suddenly get a bong and the sound is all back ok like it needs to warm up!

I've swapped my demolition man sound board to world cup and the sound kicks in straight away so I guess that rules out cables and power to the board.

Up to now I've checked the solder joints where the ribbon cable is located, also a general look around for anything that looks obviously blown but to no avail.

I'm guessing it might be a bad capacitor as it starts working after a few minutes, can't really test a cap with a multimeter though.

I did notice two of the big diodes were giving different readings to the fully working demolition man board.

Has anyone any clues how to go further?

Many thanks

Ok board doesn't bong or produce sound at all now but l can just here the speaker hiss and it pops when the power is turned off so I guess the amp may be working.

Checked the u18 and u19 chips as guide on wiki might try replacing them first.

Thanks for the reply, I've visually checked them and they seem fine.

It's as though it's a power supply issue within the board.

Using a board out of a different machine it's works fine so that cancels out ribbon cable and supplies to the board.

Something is obviously starting to work when warming up.

Ok, replaced the tantalum caps, still no difference.
I bought another soundboard which is on its way so I decided to do a stripdown and general shop of the playfield.
I replaced all the bulbs with led Inc the backbox.
Turned it on and the sound now works perfectly!!!!
Strange because the board from world cup soccer worked no problem and I checked the ac and DC voltages.

Once the other sound board arrives I might keep it just in case.

No, just the playfield. Kinda weird, maybe a power issue but the other board worked ok before I swapped to led's