Right...... they always have a hidden history don't they 😀
So are you saying that with the opamps removed that there is audio, and that when you put them back there isn't ?
So are you saying that with the opamps removed that there is audio, and that when you put them back there isn't ?
So it sounds like the problem is man-made.
There is always a possibility the opamps have been damaged... anything could have happened... so anything is possible.
If you have no test gear (scope) then fit the opamps, check the supply voltage is correct on all of them as measured on the opamp pins. Check the DC output voltage of each opamp output is close to zero.
Using headphones you should have pretty loud audio on pins 1 and 7 of both the opamps.
Maybe there is some cracked or damaged print... it should be an easy fix though.
If the opamps are suspected (unlikely both are faulty) then fit something like the cheap TL072 to prove it.
There is always a possibility the opamps have been damaged... anything could have happened... so anything is possible.
If you have no test gear (scope) then fit the opamps, check the supply voltage is correct on all of them as measured on the opamp pins. Check the DC output voltage of each opamp output is close to zero.
Using headphones you should have pretty loud audio on pins 1 and 7 of both the opamps.
Maybe there is some cracked or damaged print... it should be an easy fix though.
If the opamps are suspected (unlikely both are faulty) then fit something like the cheap TL072 to prove it.
That looks easy to measure and work on. You are going to have to get technical and start testing and measuring. All the evidence will be there. Just work from left to right on the diagram and see where the audio disappears. If there is no audio at the first opamp then replace it to eliminate it.
Nad c-541i
Friend found spare jrc2114d i inserted in to socket but like before only sound if i put amplifier volume to the end im not sure if they are compatible since there was 2604 op amp in original player not modified.
I apriciated all your help.
Friend found spare jrc2114d i inserted in to socket but like before only sound if i put amplifier volume to the end im not sure if they are compatible since there was 2604 op amp in original player not modified.
I apriciated all your help.
The 2114 should be fine, its a good quality bjt type opamp a bit like the NE5532.
You need to rig up some way that will let you probe the audio along its route, be that headphones or making an "open" lead (that connects to the amplifier) so that you can probe the audio. But be careful, make sure any points you probe are at zero volts DC first, otherwise you will hear loud cracks and pops as you couple it up.
You need to rig up some way that will let you probe the audio along its route, be that headphones or making an "open" lead (that connects to the amplifier) so that you can probe the audio. But be careful, make sure any points you probe are at zero volts DC first, otherwise you will hear loud cracks and pops as you couple it up.
Nad c-541i
If i connect headphones on pin 1 and 7 on op amp there is no sound on headphones.
regards
If i connect headphones on pin 1 and 7 on op amp there is no sound on headphones.
regards
And is that the same on both opamps ?
(back in post #11 I think you mentioned there was audio somewhere).
If you have no audio on either opamp then that's not promising at all and you would really need to investigate it all properly with a 'scope. Make sure you have the headphones connected correctly with the headphones connecting to chassis (audio ground) correctly.
(back in post #11 I think you mentioned there was audio somewhere).
If you have no audio on either opamp then that's not promising at all and you would really need to investigate it all properly with a 'scope. Make sure you have the headphones connected correctly with the headphones connecting to chassis (audio ground) correctly.
Nad c-541i
So this is a mess i got sound on left op amp looking toward rca connectors on pin 1 this is the only sound i got pin 7 nothing from the right op amp nothing from pin 1 and 7.
regards
So this is a mess i got sound on left op amp looking toward rca connectors on pin 1 this is the only sound i got pin 7 nothing from the right op amp nothing from pin 1 and 7.
regards
So audio on pin 1 of U305
That audio should carry through and appear essentially the same at pin 7 of the same IC. The second opamp in that package (U305B) is used as little more than a buffer.
Have you looked carefully at the circuit board underneath to make sure there is no damage or broken print ? It sounds like there is something fundamentally simple wrong with all this.
That audio should carry through and appear essentially the same at pin 7 of the same IC. The second opamp in that package (U305B) is used as little more than a buffer.
Have you looked carefully at the circuit board underneath to make sure there is no damage or broken print ? It sounds like there is something fundamentally simple wrong with all this.
Look at the circuit.
The audio passes through the three series resistors R363, R367 and R371 on its way from pin 1 to the input on pin 5.
I think you might have some damage and breaks in the PCB tracks. Look at the circuit at all times and try and trace the circuit continuity with your meter (player OFF for that) and make sure that pin 1 goes where it should via all those resistors. Make sure all the other opamp pins are going to where they should too.
Concentrate on that one opamp for now and fix that problem first.
The audio passes through the three series resistors R363, R367 and R371 on its way from pin 1 to the input on pin 5.
I think you might have some damage and breaks in the PCB tracks. Look at the circuit at all times and try and trace the circuit continuity with your meter (player OFF for that) and make sure that pin 1 goes where it should via all those resistors. Make sure all the other opamp pins are going to where they should too.
Concentrate on that one opamp for now and fix that problem first.
Yes, it is possible but much more likely poor soldering or a break or crack in the print around and under those sockets.
Switch the player off and then try and confirm the pins on the actual opamp go to where they should on the circuit.
For example, if you remove the IC from the socket then you should be able to measure approximately 5.9k between pin 1 and pin 5 (those resistors added together in series) and you should read a short between pin 6 and pin 7.
Switch the player off and then try and confirm the pins on the actual opamp go to where they should on the circuit.
For example, if you remove the IC from the socket then you should be able to measure approximately 5.9k between pin 1 and pin 5 (those resistors added together in series) and you should read a short between pin 6 and pin 7.
Nad c-541i
Here are the readings from u305 socket , from pin 1 and 5 there is 5,89k and 00,3 on pins 6 an 7 on the other socket there is 5,29 on pins 1 and 5 and on pin 6 and 7 there is 15,12k.
Here are the readings from u305 socket , from pin 1 and 5 there is 5,89k and 00,3 on pins 6 an 7 on the other socket there is 5,29 on pins 1 and 5 and on pin 6 and 7 there is 15,12k.
The readings for U305 are OK.
For U306 the pinouts are different because the opamps in the package are swapped around. Look at the diagram and the pin numbers and it will make sense 🙂
Back to U305, you should be able to hear the audio on pin 7 (if its OK on pin 1 it should be OK on pin 7).
If its not then look and see if the output is shorted at all. Try removing C368 and C379. Does the audio appear now on pin 7 ?
The DC voltage on pin 7 should be around zero.
For U306 the pinouts are different because the opamps in the package are swapped around. Look at the diagram and the pin numbers and it will make sense 🙂
Back to U305, you should be able to hear the audio on pin 7 (if its OK on pin 1 it should be OK on pin 7).
If its not then look and see if the output is shorted at all. Try removing C368 and C379. Does the audio appear now on pin 7 ?
The DC voltage on pin 7 should be around zero.
- Status
- Not open for further replies.