Peavey 16FX mixer input noise

[tonepumpamps]

Hello eveyone,
I have a question on a peavey fx series mixer.
One channel on the mixer develops a huge hiss after being on a couple of minutes. I believe it's in the input board. The noise is before the insert jack, I checked.
I replaced the first 4565 op amp and the two 2SD786S transistors (peavey's recommendation)
The good news is the hiss is gone, the bad news is the gain control doesn't work. I'm assuming I might be having trouble with the opamp I replaced beings it's an smd part and in a tight spot. Not to easy to solder.
I'm mostly a tube amp guy & know just enough solid state stuff to get me in trouble
Just wondering if anyone has any tips on why the gain isn't working?

Thanks!

[Jazz P Bass]

Could you be so kind as to post the complete schematic?

Those bitmaps are unreadable if enlarged.

[Enzo]

If it were mine, the first thing I would note was that the gain trim is on a separate board from the input circuits. Look to see that there is continuity from the input stuff over to the control and back. Did you have the control out of the mixer? Could it have been damaged then?

[tonepumpamps]

Sorry about the images. I'll download some different ones.
I should also mention that although the gain control doesn't work, (it is on a separate board from the input jacks) it acts like it's about halfway up when compared to the other channels.
I did have the board with the gain control out & I did check to see if something got damaged, that was the first thing I thought of.

[Enzo]

You will want to check continuity through that control FROM THE OTHER BOARD.