Here a defect Soundmagus , like the Massive D16000. This a dubble D8000 bridged or Sinus Live SLA7000
One amp board is OK
The other board has without load 1,5v dc offset, goes up when input signal (50Hz sinus) goes up.
With load no DC offset but the railvoltage on one side go up to 135V. One capacitor 3300uF/100V railvoltage was blown as a result.
Checked:
output coils OK (about the same mH unsoldered)
output mosfets OK
6N137 one defect, replaced
Q77 / Q78 defect replaced
3300uF 100V replaced
driverboard amp checked and replaced all IC's.
Same result, any help..?
One amp board is OK
The other board has without load 1,5v dc offset, goes up when input signal (50Hz sinus) goes up.
With load no DC offset but the railvoltage on one side go up to 135V. One capacitor 3300uF/100V railvoltage was blown as a result.
Checked:
output coils OK (about the same mH unsoldered)
output mosfets OK
6N137 one defect, replaced
Q77 / Q78 defect replaced
3300uF 100V replaced
driverboard amp checked and replaced all IC's.
Same result, any help..?
Last edited:
Working on other amps but continuing with this one...
Railvoltage doesn't change when driving signal on the inputs.
The railvoltage is about +/-85V without load and with 4 ohm load: +85V /-135V.
On both vertical placed cards with the 6N137 (both exchanged) I measure without load:
1: -85Vdc
2: -85Vdc
3: -85Vdc
4: -85Vdc + triangle 28kHz / 5V
5: 0V
6: triangle 28kHz/5V
other card:
1: 0V
2: 0V
3: triangle 28kHz /5V
4: +1,5Vdc and goes up with amplitude audio in (has to be +85V???)
5: +1,5Vdc and goes up with amplitude audio in
6: +1,5Vdc and goes up with amplitude audio in
The last value's are not correct, the 1,5Vdc is on the speakerterminals also.
On the mosfets IRF640 in the outputstage I measure:
low side:
G: -85Vdc
D: +1,5Vdc to output filter
S: -85Vdc
high side:
G: +1,5Vdc
D: +85Vdc
S: +1,5V dc to output filter
Diagram is very welcome!
Railvoltage doesn't change when driving signal on the inputs.
The railvoltage is about +/-85V without load and with 4 ohm load: +85V /-135V.
On both vertical placed cards with the 6N137 (both exchanged) I measure without load:
1: -85Vdc
2: -85Vdc
3: -85Vdc
4: -85Vdc + triangle 28kHz / 5V
5: 0V
6: triangle 28kHz/5V
other card:
1: 0V
2: 0V
3: triangle 28kHz /5V
4: +1,5Vdc and goes up with amplitude audio in (has to be +85V???)
5: +1,5Vdc and goes up with amplitude audio in
6: +1,5Vdc and goes up with amplitude audio in
The last value's are not correct, the 1,5Vdc is on the speakerterminals also.
On the mosfets IRF640 in the outputstage I measure:
low side:
G: -85Vdc
D: +1,5Vdc to output filter
S: -85Vdc
high side:
G: +1,5Vdc
D: +85Vdc
S: +1,5V dc to output filter
Diagram is very welcome!
Last edited:
I had a similar problem with an audiopipe 3000 (two ACPL-15001Ds bridged in one heatsink) that come in on Monday.
The voltage on one half would go from ±65v to -65 and +100v, even though the amplitude from the transformer was only 65v (more voltage out of the rectifier than the voltage going into it).
After disabling most everything in the drive circuit so that amp would cooperate, I found that C32 was either open or out of tolerance. I paralleled a 220pf across it (haven't yet measured the value of the corresponding capacitor in the other circuit) and the drive circuit began to work properly. Undoing all of the jumpers that I had in place to disable the other parts of the circuit showed that the amp was working properly and the rails no longer drifted up.
The voltage on one half would go from ±65v to -65 and +100v, even though the amplitude from the transformer was only 65v (more voltage out of the rectifier than the voltage going into it).
After disabling most everything in the drive circuit so that amp would cooperate, I found that C32 was either open or out of tolerance. I paralleled a 220pf across it (haven't yet measured the value of the corresponding capacitor in the other circuit) and the drive circuit began to work properly. Undoing all of the jumpers that I had in place to disable the other parts of the circuit showed that the amp was working properly and the rails no longer drifted up.
Bypassed the drivercard capacitor C32 with 180pF without any changes in the amp behaviour.
btw, I measured on the good working other board the railvoltage of +/-75V and no dc offset without load. And slightly higher idle current about 1,5A.
The defective board the railvoltage is +/-85V idle current 1A, maybe because there is no oscillation and a lower load for the power supply?
I 'll swap the driverboards from the boards.
btw, I measured on the good working other board the railvoltage of +/-75V and no dc offset without load. And slightly higher idle current about 1,5A.
The defective board the railvoltage is +/-85V idle current 1A, maybe because there is no oscillation and a lower load for the power supply?
I 'll swap the driverboards from the boards.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.