sure you got the top connector on the right way?
I have a Dracula, that drove me nuts until I realized
the top connector was on backwards.

Is it the original MPU or aftermarket?

If it was working properly at one time, then I would lean more towards the ribbon cables being bad. If it was always messed up then I would suggest getting new 5101's. This game and other SB 300 sterns need the fast access 5101's to play their sounds correctly.

The ribbon cables are notorious for going bad in this era of stern. The guy that you got the sound board from sells a new set. The 5101s are at u8 and u13. Start with the ribbon cables, and then we can diagnose further is need be.

I am having the sane ussue and the ball isnt ejecting. I have been told to check the fuse on the bottom of the playfield and the solenoid.

Yes, just like yours.
All my fuses are good.
Are your coils firing when you run a self test?

Does solenoid test work? If no check the fuse under the PF near the flippers.

I think the background noise is continuously starting over because the game is not feeding the ball to the shooter lane is my guess. Tries to feed the ball to shoot lane. Coil doesnt fire. Game sees ball is still in trough. Does end of ball routine which makes the background noise starts over. And that goes on for a never ending loop.

Hit the test button on the coin door twice.
The game will fire coils in order, from 1 to 2x. The coil number that is firing should appear on the displays. In the 20s, the 'coils' are sounds. That is normal. It will then repeat the process.

Shouldnt this be in the vintage pinball area and not posted in the modern Stern section ?

I had a similar problem and it ended up being my aftermarket driver board putting out too much voltage.

i think the issue is lack of solenoid power on the PF. Sound repeats because the game sees the ball constantly in the outhole so it does its end of ball stuff on a loop.

If the 43v was gone entirely the game would not boot up all the way. So most likely situation is the solenoid fuse is probably blown on pf. look under pf near the flippers. Should be 1.5a slow blow or so. Check for 43v dc on each side of this fuse. If missing from both sides of the fuse check rectifier board connectors like the playfield plug. Make sure you re pinned it proper.

its in the manual. transformer assembly / rectifier schematic page. j1 p6

Another tip: Had this similar problem show up at a show.
All fuses tested good on the rectifier board, board was brand new. Turned out the fuse clip for the PF solenoids was a bit loose. With fuses out, pinch together to create more "grab" for the fuse.