HK730 Blows all four fuses

[hakno]

Hi

I dropped my HK730 while trying to clean it and it landed on the corner where the on/off button is, since then it blows all four fuses as soon as I turn either of the speakers A/B on.
The reciver starts up fine and lights up but as soon as i turn either of the speaker outlets on it blows all four fuses, quite instantly one after the other.
I even tried to remove the Power Amp but it still blows all four fuses when i turn the speakers on.
The speakers are disconnected.

I´ve tried to see if anything is obviously out of place and I have done some testing with my mulitmeter but don´t know really where to start. I would like some help on how to do this in a way that I pice by piece can rule out diferent parts of the Amplifier.

Any help is greatlly appreciated.

 

[Athers-Aud]

Often a drop and cause over stress to the chassis causing cracks in the printed circuit board that need repairing, and/or something bent over that is now connecting to power carrying areas it shouldnt.

 

[hakno]

Looking at the schematics it seems the first converging point after the speaker selectors is the pre amp section. Am I correct to start looking for a fault there?