Hello beachycove,

how did you clean the mainboard?

And I have a service manual auf the 840AV, but the pics are very bad, so I didn't know how to disassemble the 840 correctly :-(

And what kind of error was shown by your Quadras in detail?

It's really hard for me to detect the error correctly, because I didn't know if it's normal that the 840 throw out every diskette and if this is normal when the capacitors are leaked? I have also tried a System 7.5 disc.

Don't know where to start and how to isolate the error.

Thanks in advance