Every 5 to 6 amplifiers I get on my bench has something I can't figure out.
I have a dba 1600.1D on my bench.
1. Powers up no shorts, all Power SW50N06, Output 2SC520 and Rectifiers F12020A & F12020C tested good.
2. At idle it consumes .56 amps with no voltage drop.
3. T494 tested good, has +12v on pin 12 and -0v on 7. no pwm on e1 or e2, has .347v on pin 4
4. Op-Amps have nothing. I replaced the PC817 Optocoupler.
5. 12v on both rails.
6. Changed both diodes in5408. changed all transistors down the middle.
7. I get 12v on primary side of the transformer and only 7.4v on secondary side.
8. I tested all resistors and diodes.
I have a dba 1600.1D on my bench.
1. Powers up no shorts, all Power SW50N06, Output 2SC520 and Rectifiers F12020A & F12020C tested good.
2. At idle it consumes .56 amps with no voltage drop.
3. T494 tested good, has +12v on pin 12 and -0v on 7. no pwm on e1 or e2, has .347v on pin 4
4. Op-Amps have nothing. I replaced the PC817 Optocoupler.
5. 12v on both rails.
6. Changed both diodes in5408. changed all transistors down the middle.
7. I get 12v on primary side of the transformer and only 7.4v on secondary side.
8. I tested all resistors and diodes.
Power supply came alive, Rectifiers low side -38.4 and high side +50.2 on center pin.
We have pwm and nothing is getting to hot, under 100 except the resistors in front of the transformers 148.
No pwm on output. The Op-Amps has +7.47 on all 8 pins.
Amp at idle is .548 amps no voltage drop.
Forgot to say red light is off green is on.
We have pwm and nothing is getting to hot, under 100 except the resistors in front of the transformers 148.
No pwm on output. The Op-Amps has +7.47 on all 8 pins.
Amp at idle is .548 amps no voltage drop.
Forgot to say red light is off green is on.
I should have explained myself better, my bad.
I got no audio on any op-amps using a Oscilloscope with input audio playing and amp powered.
I was using the probe in picture to trace audio from RCA with input audio playing and amp powered when i got audio from pin 4 and 8.
Using this cable I can trace audio path.
Please forgive my drawing.
I got no audio on any op-amps using a Oscilloscope with input audio playing and amp powered.
I was using the probe in picture to trace audio from RCA with input audio playing and amp powered when i got audio from pin 4 and 8.
Using this cable I can trace audio path.
Please forgive my drawing.
Sorry it took so long. You added a lot more info in your update tutorial.
I did read the "Audio Troubleshooting page" like you said and more. It turned out to be one of the big gray resistors and a transistor. Your tutorial helped me fix this amp. I test them on normal speakers/subs but I get very tired of listening. I need to buy them dummy resistors. I see some on eBay 4ohms 100watts for about $23. Will this one 4ohms 500watts work from Amazon?
Thanks again for all your help!
Jean
I did read the "Audio Troubleshooting page" like you said and more. It turned out to be one of the big gray resistors and a transistor. Your tutorial helped me fix this amp. I test them on normal speakers/subs but I get very tired of listening. I need to buy them dummy resistors. I see some on eBay 4ohms 100watts for about $23. Will this one 4ohms 500watts work from Amazon?
Thanks again for all your help!
Jean
Adding more every day. It's good that you seem to be reading more than just the parts that you think you need for a particular repair. Many buyers never read half of what's included.
A lot of people are using the resistors you linked to. I prefer the cylindrical types but you can use whatever you want.
I'd suggest monitoring the output as is shown at the end of item #9 on the equipment page when using dummy loads. Also read item #5 and follow the link in the section reading:
A lot of people are using the resistors you linked to. I prefer the cylindrical types but you can use whatever you want.
I'd suggest monitoring the output as is shown at the end of item #9 on the equipment page when using dummy loads. Also read item #5 and follow the link in the section reading:
- For 'bench testing' to confirm that the amp has been properly repaired, read THIS section of the Repair Introduction page.
