Search from the rtconfig file inside the theme these lines:
Code:
set master.mcp.meter [6 680 12 230 0 1 0 1]
set master.mcp.meter.vu.div [2]
set master.mcp.meter.readout.color [0 0 0 0]
set master.mcp.meter.rmsreadout.color [0 0 0 0]
set master.mcp.meter.scale.color.unlit.top [0 0 0]
set master.mcp.meter.scale.color.unlit.bottom [0 0 0]
set master.mcp.meter.scale.color.lit.top [10 0 0 0]
set master.mcp.meter.scale.color.lit.bottom [30 30 30]
The colors might have been set to zero or something which blends with the meter background, so you'll have to change them to suit you better. Notice also that the meter has to be at least 13 px wide for the scales to show. In the example above the width is 12 px.
Same thing applies for the tcp.meter, master.tcp.meter and mcp.meter also.