Gallien_Krueger 700 rb II short

[g1]

The board that I have got is of the series 206-0250-B2 and there is cable coloring printed on the board. This is what i have followed and I i have now confirmed that the cabling is correct according to the printed color coding on the board.

Can you post a picture of the board coding/labelling?
Does the labelling on the board state that it is for 230V operation?
If not, you should assume the labelling is for 120V as GK is a US based company. That is why I asked you to compare your wiring to the picture of the transformer wiring.
The power switch can not make the fuse blow unless it shorts to the chassis.

[Enzo]

g1, look at the photo in post #26.


The power switch is before the fuse, so if you remove the fuse and it no longer blows fuses, then the switch is not involved.

[g1]

Ok, thanks for pointing out the pic Enzo, I had posted the wrong revision drawing in post #28 which I have corrected.
His picture matches the drawing.
As far as I can tell it can only be a bad power transformer.

[The Dude]

This is a bit difficult to explain, so hopefully you can follow.

There is a metal shield between the transformer and the preamp board bolted to the chassis and sticking up vertically inside the unit. Often times, in this amp series, the transformer slides into one of the screws sticking up into the chassis that holds the shield in place nicking into the transformer and shorting to the chassis via the screw. Sometimes, it wrecks the transformer. Other times, it's just a small nick. Once you remove the transformer and cover the scratch, it will remove the short to the chassis. If that is the case, either replace the screw with a shorter one or grind it off so it's not sticking up into the chassis as far. Then, make sure you tighten the transformer back down well so that it can't slide into the area where the screw sticks up. It's worth having a look before ordering an expensive transformer. You just need to remove the transformer and have a look at the underside to see if what I've described is what's happening.

Edit: I edited your picture to better explain.