I am having a problem with a Mojotone Vibrolux 5f11 kit I built early last year. When I finished the amp everything worked just fine, including the tremolo. Recently, the tremolo has developed a thumping. It is present with nothing plugged in and the volume and tone controls set at the minimum. It increases in volume as the intensity control is turned up, and it increases in speed when the speed control is turned up. I have tried chopsticking the wires with no change. I have tried different pairs of power tubes and different 12ax7 tubes in place of V1 with no change. Voltages (excluding heaters) are as follows:
V1
pin 1: 213
pin 2: 0.0
pin 3: 1.61
pin 6: 217
pin 7: 0.02
pin8: 1.69
V2
pin 1: 212
pin 2: 0.0
pin 3: 1.64
pin 6: 257
pin 7: 22
pin8: 56.1
V3
pin 1: 0.0
pin 3: 404
pin 4: 407
pin 5: -38
pin 6: -38
V4
pin 1: 0.0
pin 3: 404
pin 4: 407
pin 5: -38
pin 6: -38
I've attached the schematic and some photos of the wiring related to the tremolo. I would appreciate any help in tracking down the source of the problem.
Thanks
V1
pin 1: 213
pin 2: 0.0
pin 3: 1.61
pin 6: 217
pin 7: 0.02
pin8: 1.69
V2
pin 1: 212
pin 2: 0.0
pin 3: 1.64
pin 6: 257
pin 7: 22
pin8: 56.1
V3
pin 1: 0.0
pin 3: 404
pin 4: 407
pin 5: -38
pin 6: -38
V4
pin 1: 0.0
pin 3: 404
pin 4: 407
pin 5: -38
pin 6: -38
I've attached the schematic and some photos of the wiring related to the tremolo. I would appreciate any help in tracking down the source of the problem.
Thanks
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