Gallien-Krueger MB150S Service Manual page 14

RETURN AND STEREO AUX IN TEST
1) Set AC-VM to 10V scale.
2) Set oscillator to 100 sine wave at –26dBV (50mV).
3) Insert plug from oscillator into return jack (J6).
4) Set output to 10. Output = 2Vrms.
5) Insert plug from oscillator half-way into stereo aux. in jack (J5). Output = 3.5Vrms.
6) Push plug in rest of way. Output should be same as above.
NOISE TEST
1) Remove oscillator input.
2) Turn large knobs to 10, small knobs to 0, switches out.
3) Connect speaker to output, listen for noise. It should be clean with no crackling or distortion.
4) Change AC-VM range to 0.1V.
5) Noise should measure less than 30mV.
6) Engage low-cut, hi-boost and contour to 10. Noise < 150mVrms.
7) Voicing filters off or to 0, boost to 10, chorus on.
8) Noise < 200mVrms.
RETURN KNOBS TO ZERO- READY FOR BURN-IN