Replaced LM317 and using the amps ground terminal as reference even the new LM317 has 50 volts on the output (leg 3)
I removed the LM317 and used the amps ground terminal for reference .
Even with the LM317 Removed I get 50 volts on all 3 pads for it .
Even with the LM317 Removed I get 50 volts on all 3 pads for it .
Here is what I get between the pads
Legs 1-2:121 ohms
Legs 1-3:1.951 M ohms
Legs 2-3:1.349 M ohms
Legs 1-2:121 ohms
Legs 1-3:1.951 M ohms
Legs 2-3:1.349 M ohms
What is the rail voltage in this amp?
What are the values in the board for resistors R21, R22, R27 and R28?
What are the values in the board for resistors R21, R22, R27 and R28?
At the opamps I get -18 volts and positive 17 volts .
At the regulator I get 50 volts on all 3 legs still .
R310,311,313 I get 50 volts measured directly across the pads
R211,210,213 I get 20 volts measures across the pads .
So I’m assuming this is why the resistors are burning up .
Is it normal to have correct regulated voltages at the opamps but 50 volts at the regulator ?
At the regulator I get 50 volts on all 3 legs still .
R310,311,313 I get 50 volts measured directly across the pads
R211,210,213 I get 20 volts measures across the pads .
So I’m assuming this is why the resistors are burning up .
Is it normal to have correct regulated voltages at the opamps but 50 volts at the regulator ?
I don't see how that's possible.
What's the resistance between pin 8 of the op-amps and the output terminal of the 317?
What's the resistance between pin 8 of the op-amps and the output terminal of the 317?
From pin 8 of the opamp to middle pin of the 317 : 2.460k ohms
If I use the amps ground terminal as reference I get the following voltages on the LM317
Pin 1: 44.6 volts. (Adjust)
Pin 2:47.2 volts. (V out)
Pin 3:50.5 volts. (V in )
On the opamps I get
Pin 4:-18.5
Pin 8:-17.9
If I use the amps ground terminal as reference I get the following voltages on the LM317
Pin 1: 44.6 volts. (Adjust)
Pin 2:47.2 volts. (V out)
Pin 3:50.5 volts. (V in )
On the opamps I get
Pin 4:-18.5
Pin 8:-17.9
There is a conflict between the pin 8 voltage in posts 32 and 34.
You can't have 50v across R32. It would burn in seconds.
Measure the DC voltage directly across it.
You can't have 50v across R32. It would burn in seconds.
Measure the DC voltage directly across it.