Gallien-Krueger 200MB Service Manual - page 7
Note: Trigger is on the channel, the scope probe is on, and connect to D.0 (J5) @ 1V/div. This will make it
possible to make measurements without having trigger problems. An external trigger could also be used.
A) Volume at 9 o’clock
B) Master at 10.
C) Tones on 5.
D) Engage chorus.
E) Rate 0/ Depth 0. Deviation = 1.3 sec. / Rate = 1.5 sec.
F) Rate 0/ Depth 10. Deviation = 5.0 sec.
G) Rate 10/ Depth 10. Rate = .25 sec.
H) Disengage chorus.
25)
Balance out test. Sine input (400Hz 50mVrms) –26.0dB.
A) Volume on 5.
B) Master on 10.
C) Tones on 5. Balance out left pins 2 and 3 and balance out right pins should look different. Left
should swell up and down to a min. and max. value. Right should do the same, however
oscillate right and left.
D) Engage chorus.
E) Stereo switch out.
F) Push in stereo switch (mono mode). Signal on left and right should look similar, swelling up and
down.
G) Chorus off.
26)
Check speaker cut-off switch.
27)
Disconnect input.
28)
Proceed with noise and tap test.
A) Controls on 10, switch out = noise <60mVrms.
B) Controls on 10, contour in = noise <80mVrms.
C) Controls on 10, comp. in, sustain 0 = noise < 50mVrms.
D) Controls on 10, comp. in, sustain 10 = noise< 250mVrms.
E) Controls on 10, comp. in, sustain 10 = noise< 300mVrms.
F) Contour in, chorus in = noise< 40mVrms.
G) Contour in, master on 0= noise< 2.5mVrms.
Noise should be clean without popping or cracking.