Nad cd player C-541i

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#41
Nad c-541i

Mooly said:
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.
Click to expand...

There is a lot of voltage on pin 7 definitely not zero if i measured correct it is 125,2mv the player is on.
 
#42
That doesn't sound correct. (The player should be in stop mode for that reading). We can still work with those readings though to see if any problem shows up.

You should have an identical voltage (125mv) on pin 6, check it !

And you should have that same voltage also on pin 5. Check it !
 
#43
Nad c-541

Mooly said:
That doesn't sound correct. (The player should be in stop mode for that reading). We can still work with those readings though to see if any problem shows up.

You should have an identical voltage (125mv) on pin 6, check it !

And you should have that same voltage also on pin 5. Check it !
Click to expand...

Yes the same value also on the pin 6 and 5 palyer is on and in stop mode.
 
#50
Are the fuses OK ?
 

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#52
Just measure the voltages... have confidence in what you are doing 🙂

If the plus and minus 12 volts are present then the regs are OK. You say the voltage is low on the opamp pin 8... so check it on the regulator. There might be a break or crack in the print.

Find the problem by measurement, not guessing 😉
 
#53
Nad c-541i

Mooly said:
Just measure the voltages... have confidence in what you are doing 🙂

If the plus and minus 12 volts are present then the regs are OK. You say the voltage is low on the opamp pin 8... so check it on the regulator. There might be a break or crack in the print.

Find the problem by measurement, not guessing 😉
Click to expand...

Agree with you guessing will not solve the problem i measure also the regulator and again on the op amp but there is no 12 volts present if i check the regulator adjs.pin 1 and pin 2 v.out there is 3,57v present.

regards
 
#56
And is there at least 15 volts going in to the regulator ?

If you look at the diagram of the PSU you will see there is a relay feeding the AC from the transformer into the bridge rectifier. If there is no 15 volts (or higher) then check the relay action is OK.
 
#57
Nad c-541i

Mooly said:
And is there at least 15 volts going in to the regulator ?

If you look at the diagram of the PSU you will see there is a relay feeding the AC from the transformer into the bridge rectifier. If there is no 15 volts (or higher) then check the relay action is OK.
Click to expand...

I noticed that there are two regulatorsU507 and U501 in the power suply but the U507 is so hot not sure if this is correct i will look tomorow also the relay.

regards
 
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