Galien & Krueger MB150E

[MarkusBass]

I've been looking for these - the board version is 6087 (from circa 1995). This is the version with chorus effect.
I have the newer schematic version 6220 (from 2003), which helps, but would like to have the older version because the PC board is different and the component symbols are different.
Someone has modified the amp by replacing TL072 with LF353 (which is good) but also by removing the DG419 analog keys and cutting some tracks. As a result the amp does not work correctly. I have to revert all the changes.

Mark

[DrGonz78]

Might not be the one but I will post it anyway to make sure... Look at page 6 and 7 to see if that is what you needed.
dropcanvas - instant drag and drop sharing - canvas view

[MarkusBass]

Great, this is exactly what I needed. Thank you so much. It appears that LF353 where initially used in this version of the amp. So someone tried to use other op amps (that's why the sockets are on the board). But he also removed analog keys (2xDB419 - they are missing) , one transistor and shorted some parts of the circuit (see the blue wires on the bottom of the board). And the amp does not work correctly now (especially all the XLR outputs). This is difficult but with the schematic it will be a little bit easier. Thanks again.

[g1]

I'll also add this one, which is a bit older.

[MarkusBass]

Thanks. This is the same schematic but a little bit older (from 1991 compared to 1995). There are just some small differences: this one used TL604 as the analog switch. The newer one used DG419 analog switch. The older schematic has U15 as the TL604 component designator, while on the newer schematic this designator is missing. But it is present on the PC board.
It seems to me that the amp had some problems with the XLR outputs. I see signs of fire here:



And I think that this was not fixed correctly.

Mark