This amp isn’t producing any positive regulated voltage.
I removed the opamps since 1 of them was defective and still couldn’t get the +15 volts .
All opamps for this amp still have voltage on all pads even after they have been removed from the board .
I removed the regulator also and all 3 pads for the regulated have voltage on them .
Any ideas ?
I removed the opamps since 1 of them was defective and still couldn’t get the +15 volts .
All opamps for this amp still have voltage on all pads even after they have been removed from the board .
I removed the regulator also and all 3 pads for the regulated have voltage on them .
Any ideas ?
Attachments
OK. Ground the non-bridging terminals and post the DC voltage on all terminals of one op-amp and the all terminals of both regulators.
In the future, don't just say that you have voltage on a point without posting the voltage that is on those points.
In the future, don't just say that you have voltage on a point without posting the voltage that is on those points.
NE5532
Pin 1:0.00
Pin 2:0.00
Pin 3:0.00
Pin 4:-14.72
Pin 5:0.00
Pin 6:0.00
Pin 7:0.00
Pin 8:14.75
Q20 2N6488:
Base:15.15
Collector:30.21
Emitter:14.76
Q21 2N6491
Base:-15.23
Collector:-30.24
Emitter:-14.78
This is with the non bridging speaker terminal grounded
Pin 1:0.00
Pin 2:0.00
Pin 3:0.00
Pin 4:-14.72
Pin 5:0.00
Pin 6:0.00
Pin 7:0.00
Pin 8:14.75
Q20 2N6488:
Base:15.15
Collector:30.21
Emitter:14.76
Q21 2N6491
Base:-15.23
Collector:-30.24
Emitter:-14.78
This is with the non bridging speaker terminal grounded
Do you only lose the +15v on the op-amps?
What other voltages change compared to the voltages posted on #5?
What happens if you plug in a signal source with a grounded shield, instead of grounding the speaker terminals?
What other voltages change compared to the voltages posted on #5?
What happens if you plug in a signal source with a grounded shield, instead of grounding the speaker terminals?
If I plug in the signal source I get the 15 volts on the opamps .
Wondering in these amps are the regulators supposed to get to hot to touch ?
And I guess I have to use the non bridging speaker terminals in This amp to get the correct readings and not use main ground when testing the regulated voltages
Wondering in these amps are the regulators supposed to get to hot to touch ?
And I guess I have to use the non bridging speaker terminals in This amp to get the correct readings and not use main ground when testing the regulated voltages
Nothing has changed .
I was using amps ground terminal as ground reference at first so I had 2 volts on pins 1,2,3,5,6,7 of the opamps .
If I use the secondary ground all voltages are correct and pins 1,2,3,5,6,7 remain at 0.00 volts
I was using amps ground terminal as ground reference at first so I had 2 volts on pins 1,2,3,5,6,7 of the opamps .
If I use the secondary ground all voltages are correct and pins 1,2,3,5,6,7 remain at 0.00 volts
It's normal for regulators to get hot.
Some amps have an isolated secondary which prevents measuring voltage using the primary ground.
From the information that you've provided, I don't know why the +15v would be the only missing voltage when measuring the voltage using the primary ground.
Some amps have an isolated secondary which prevents measuring voltage using the primary ground.
From the information that you've provided, I don't know why the +15v would be the only missing voltage when measuring the voltage using the primary ground.
Ok got a question .
The power light on this amp consists of 5 light bulbs the originals looked like incandescent light bulbs . They were all burnt out .
I swapped them over to leds and now get the transistor that controls the 13 volts to pin 8,11,12 of the 494 to burn and blow apart .
Could switching the incandescent bulbs over to leds cause this issue ?
The power light on this amp consists of 5 light bulbs the originals looked like incandescent light bulbs . They were all burnt out .
I swapped them over to leds and now get the transistor that controls the 13 volts to pin 8,11,12 of the 494 to burn and blow apart .
Could switching the incandescent bulbs over to leds cause this issue ?