Mystery on-board preamp

[Mark Hammer]

Looking to rehabilitate a small undocumented on-board pre-amp I acquired some time ago. I think it was made by Starr Labs, back in their pre-MIDI days. It was designed to mount vertically to a pick-guard/control-plate.

It is a fairly small (about 0.6" x 1.4") SMD board with a small Bourns trimpot on it (presumably gain-adjustment), and flat-paddle handle DPDT PC-mount toggle. The toggle appears to provide bypass of the circuit, rather than any sort of power switching (which I gather was done at a stereo output jack). It uses a surface-mount LF441 op-amp.

Any help in tracking down a schematic, or even a model number and manufacturer would be helpful. I'd try and reverse-engineer it myself, but it's so damn small, and the traces run under the components.

Thanks

[fredy2]

When tracing a circuit board I have found that a bright single LED light to be useful to candle the board. You can often see where the traces go under the components. You likely have the problem fixed years ago, so this info is for others.