Behringer Ultrabass BXL1800 help

[diydidi]

I have this bass amp for repair.
The preamp section/ board is kicking my ass all over the place AARGH!!
Can anyone assist with a schematic?
It differs quite a lot from the BX models.

[Enzo]

What is wrong with it? Other than the inevitable broken jacks or controls, about all I ever have to do to any of those keyboard or bass combo behringers is replace op amps, usually TL074s.

[diydidi]

Hi Enzo.
Thanx for chipping in. Basically I have no sound. Power amp works and all voltages to front panel are present. There is a 4013 and a 4053 on there. I cant see what their supply pins are supposed to be getting. In any case, there is nothing on their supply pins. The 4013 also gets VERY hot.

[Smudger075]

Did you ever fix this as I have the same issue except I've changed most 074s and both 4013 and the 4053 but nothing. I did make an error when fitting the 4053 I hadn't connected all the pads and amp started some guitar output but very distorted but not on the headphones. I fixed the problem but now back to no guitar input. Return works with a pedal preamp and audio in works perfect.
Would love to find a schematic even a hand drawn one tried all the suggested ones.
thanks Alan

[sugeda]

...

[Smudger075]

Well I've now made progress thanks to schematic it was ic6 now we have sound but a little distorted. Working on that now, not distorted with audio so still preamp issue but great progress.