I know most of you say chuck it and get another but I can't yet so I'm stuck with it...

It's wired up to a 4xaaa pack no led connected yet.
So I test fire it up, beautiful sound (for a hasbro)
Only one sensor, clash sensor does both swings and clashes.
I've used a upgrade sensor from tcss, I tap it once quickly and I get a clash noise.

Lovely but it's followed by a horrible screech, I have no idea what it is.

Further tests show I get no swings and the same clash over and over with the noise.

Any ideas? I've cut the rumble motor off completely, could it need feedback from that?
Thanks!