I have a Rockford Fosgate t20001bd to repair.
There is NO audio to output, but if I raise much gain, distorted sound comes out.
The amplifier turns on normally and regularly produces all voltages (+ HV, -HV, +/- 15V, +/- 6V)
ALL OUTPUT DEVICES ARE NEW, so they are perfect ..
Toggle A & B are present and functioning properly.
The triangular carrier signal is present and perfect ON PIN 5 of U301 and U302.
I see a square signal on pin 1 and pin 6 of U301 and pin2 of U302 that varies as a function of the audio signal that I am using to the input of the amplifier (100HZ sinewave).
The strange thing is that I can not see any signal on pin 7 of U301 and U302.
For this reason, there is no oscillation on 2 uc3706 for fet driving.
politely, what would you do in this situation?
There is NO audio to output, but if I raise much gain, distorted sound comes out.
The amplifier turns on normally and regularly produces all voltages (+ HV, -HV, +/- 15V, +/- 6V)
ALL OUTPUT DEVICES ARE NEW, so they are perfect ..
Toggle A & B are present and functioning properly.
The triangular carrier signal is present and perfect ON PIN 5 of U301 and U302.
I see a square signal on pin 1 and pin 6 of U301 and pin2 of U302 that varies as a function of the audio signal that I am using to the input of the amplifier (100HZ sinewave).
The strange thing is that I can not see any signal on pin 7 of U301 and U302.
For this reason, there is no oscillation on 2 uc3706 for fet driving.
politely, what would you do in this situation?
Last edited by a moderator:
I'm sorry for the delay.
I checked if there DC on pins 1 and 7 of U301 and U302.
With a multimeter in voltmeter function, with the black probe connected to the main ground I measured:
U301: PIN1: DC voltage that varies between 1.5v at 4v
PIN7: fixed voltage -4.36v
U302: PIN1: DC voltage which oscillates between -1.8v to -4V
PIN7: DC voltage that varies between 5.2V and 5.5V
I do not have much experience with this type of amplifiers, for this reason, you have any idea? or some other kind of test?
I checked if there DC on pins 1 and 7 of U301 and U302.
With a multimeter in voltmeter function, with the black probe connected to the main ground I measured:
U301: PIN1: DC voltage that varies between 1.5v at 4v
PIN7: fixed voltage -4.36v
U302: PIN1: DC voltage which oscillates between -1.8v to -4V
PIN7: DC voltage that varies between 5.2V and 5.5V
I do not have much experience with this type of amplifiers, for this reason, you have any idea? or some other kind of test?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.