K4040 Fuse blows if the amp is swichting off

Hello,

i have a Problem with the K4040.
The amp works fine over 5 years, and is still working if it’s on. But when i switch the amp off, the main fuse fuse blows away.
Do you have any idea what could be wrong or whitch parts i schould check in the circuit?

Thanks for your support!

I have the same problem.Please help me.