Hello ,
i have this cd player but suddenly there is no sound from it , cd reading is ok and all controls working but no sound , i measure with multimeter on the rca output there vas 0,37 miliamp on both chanel , any help would be appriciated.
thx
regards
i have this cd player but suddenly there is no sound from it , cd reading is ok and all controls working but no sound , i measure with multimeter on the rca output there vas 0,37 miliamp on both chanel , any help would be appriciated.
thx
regards
Have you checked the supply voltages to the opamp output stages. I'm guessing you haven't got a scope... and that really is what you need to fault find problems like these.
If you know how to find your way around a circuit diagram then you could probe the analogue audio chain with a pair of headphones and series resistor to see if audio is present. Use old headphones and don't put them on your ears... just use them as a speaker.
If you know how to find your way around a circuit diagram then you could probe the analogue audio chain with a pair of headphones and series resistor to see if audio is present. Use old headphones and don't put them on your ears... just use them as a speaker.
Nad c-541i
Thx for replay , i dont have proper equipment to make that but i connect player to amplifier and get ear close to speaker there is a sound but only if i put the volume to full .
regards
Thx for replay , i dont have proper equipment to make that but i connect player to amplifier and get ear close to speaker there is a sound but only if i put the volume to full .
regards
OK, well this might sound a silly question but does the player have a user controllable mute facility. Not a common feature but some do. Does anything on the display look like a mute symbol, and that it might be active.
You can have a measure (DC voltage) on these points and see what you have got.
D404 circled should have a minus voltage on the cathode (the end with a stripe). You should also have that same voltage (whatever it is) on the left side of R414. The other side of R4114 should have a steady MINUS 12 volts.
Check those and see what you have got.
You can have a measure (DC voltage) on these points and see what you have got.
D404 circled should have a minus voltage on the cathode (the end with a stripe). You should also have that same voltage (whatever it is) on the left side of R414. The other side of R4114 should have a steady MINUS 12 volts.
Check those and see what you have got.
Attachments
Minus 5 on R414 sounds correct (and there should be minus 12 on the other end)
That tells us that the mute control voltage is correct... so the problem isn't there. And it would be to much of a coincidence for one or more mute transistors to zapped in each channel.
The next test would really help pin it down and that is to determine of there is audio on the first opamp in the chain.
That tells us that the mute control voltage is correct... so the problem isn't there. And it would be to much of a coincidence for one or more mute transistors to zapped in each channel.
The next test would really help pin it down and that is to determine of there is audio on the first opamp in the chain.
The opamp outputs marked with a cross should have ZERO volts DC present. You should be able to pick up audio on all those four points... but you need a way to determine that.
Headphones used as a speaker would work (don't wear the headphones, just see if you get audio from them). You connect the large inner part of the headphone plug to chassis and the tip of the plug is used to probe the opamp output.
Confirm there is ZERO volts first though of these points before connecting anything to them.
If there is no audio present then the problem is going to be more deeply seated and require much more testing and faultfinding.
Headphones used as a speaker would work (don't wear the headphones, just see if you get audio from them). You connect the large inner part of the headphone plug to chassis and the tip of the plug is used to probe the opamp output.
Confirm there is ZERO volts first though of these points before connecting anything to them.
If there is no audio present then the problem is going to be more deeply seated and require much more testing and faultfinding.
Attachments
Nad c-541i
Following you advice , there is a audio sound present thru headphones.
thx
regards
Following you advice , there is a audio sound present thru headphones.
thx
regards
That sounds promising. Only two possibilities really then, one is that the player has suffered physical damage around the sockets, the other that the mute transistors really are duff...
Physical damage. Check for continuity from the centre part of the RCA sockets to those 75 ohm resistors. Quick check. It should read 150 ohms from one end of C368 and C369 to the sockets. If its lower then the transistors would appear faulty. If its higher or open then you have a break in the print, probably at the socket itself.
Physical damage. Check for continuity from the centre part of the RCA sockets to those 75 ohm resistors. Quick check. It should read 150 ohms from one end of C368 and C369 to the sockets. If its lower then the transistors would appear faulty. If its higher or open then you have a break in the print, probably at the socket itself.
That sounds odd.
And you have audio (on headphones) on those two right hand opamp outputs (the two right hand red crosses) ?
If so, then using the same headphone test method, try probing the RCA sockets themselves.
And you have audio (on headphones) on those two right hand opamp outputs (the two right hand red crosses) ?
If so, then using the same headphone test method, try probing the RCA sockets themselves.
Nad c-541i
Is it possible that the laser could not read the information from the disc , despite that it has no problem from reading and playing discs , i must say that i test this player with my friend on his sistem and play well , then i bring it home and decided to change the power cord by instaling an iec inlet wich i done already several times without problems but then after plug it in everithing vas ok just no sound. I dont have any option to try also dteh digital outputs to se if that works.
thx
Is it possible that the laser could not read the information from the disc , despite that it has no problem from reading and playing discs , i must say that i test this player with my friend on his sistem and play well , then i bring it home and decided to change the power cord by instaling an iec inlet wich i done already several times without problems but then after plug it in everithing vas ok just no sound. I dont have any option to try also dteh digital outputs to se if that works.
thx
The laser sounds just fine from what you say.
If you can hear audio on the headphones by probing the opamp outputs then something simple is amiss somewhere. And if you can hear audio on the output sockets with headphones, but didn't get sound when you connected it all up to an amplifier then again, it sounds more like a connection issue to the outside world 🙂
Be methodical and work from left to right tracing the audio from the opamps to the sockets.
If you can hear audio on the headphones by probing the opamp outputs then something simple is amiss somewhere. And if you can hear audio on the output sockets with headphones, but didn't get sound when you connected it all up to an amplifier then again, it sounds more like a connection issue to the outside world 🙂
Be methodical and work from left to right tracing the audio from the opamps to the sockets.
Nad c-541i
Ok im gonna try again all steps maybe i did something wrong , i measured 0,37ma on both chanel on rca connectors if that is of some help and sound is going out but i must open volume almost to the end to hear some sounds from speaker.
thx
Ok im gonna try again all steps maybe i did something wrong , i measured 0,37ma on both chanel on rca connectors if that is of some help and sound is going out but i must open volume almost to the end to hear some sounds from speaker.
thx
The voltage on the sockets (not current) should be around zero give or take a few millivolts.
If you can drive headphones and hear the audio clearly then there is more than enough output to drive an amplifier.
Just check it all again carefully. And if you can run headphones from the output sockets then the player is fine.
If you can drive headphones and hear the audio clearly then there is more than enough output to drive an amplifier.
Just check it all again carefully. And if you can run headphones from the output sockets then the player is fine.
If you can burn a CDR then you can make your own test disc with a 0db level test tone. You could then check the player output voltage which should be around 2 volts AC playing that tone.
Nad c-541i
Im back as Arni said , i forgot to mention that i bought this cd with some sort of modification already done on cd player such as different op amp , nichicon , elna caps etc.. , then i pull out both op amps lme49720 and after that there is a huge improvmenet there is a sound comming from player and it is louder then before big different , if i put op amp back then is a sound but just a little from speaker.
regards
Im back as Arni said , i forgot to mention that i bought this cd with some sort of modification already done on cd player such as different op amp , nichicon , elna caps etc.. , then i pull out both op amps lme49720 and after that there is a huge improvmenet there is a sound comming from player and it is louder then before big different , if i put op amp back then is a sound but just a little from speaker.
regards
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