Hey there,
picked up a NAD as bargain basement (£15) and to be honest a bit of a risk.
Its a NAD C542i, and had some power issues, which I had down as a bit of dry solder on the connector from the transformer to the main board.
Managed to fix that, and device powered up properly.
However, stick in a CD and... well nothing, doesn't spin up, the laser does nothing. I've got a copy of the service manual which suggests that it's either the u101 (chip on the m/board) or the connection/ pickup.
So the question is whether it is worth bothering and trying a new mechnism, or simply put it down as a risk taken and lost?
Cheers for your thoughts
picked up a NAD as bargain basement (£15) and to be honest a bit of a risk.
Its a NAD C542i, and had some power issues, which I had down as a bit of dry solder on the connector from the transformer to the main board.
Managed to fix that, and device powered up properly.
However, stick in a CD and... well nothing, doesn't spin up, the laser does nothing. I've got a copy of the service manual which suggests that it's either the u101 (chip on the m/board) or the connection/ pickup.
So the question is whether it is worth bothering and trying a new mechnism, or simply put it down as a risk taken and lost?
Cheers for your thoughts
The platter won't spin until the laser focuses onto a disc, so no spin is normal.
The very first thing to check is to confirm that when the drawer shuts, it does so fully and that any subsequent mechanical loading of the mechanism finishes. I'm not familiar with the NAD but slipping loading belts (if it uses them) can cause such problems.
There will be some form of micro switch to detect the drawer is closed. If that isn't happening then the drawer motor will keep running. So make sure that is OK.
Also check that the laser assembly is correctly positioned at the centre of the disc. It can be a useful check to manually move the pickup outward (turn the sled motor by hand with the player off) and then reconnect power and turn on. The sled should instantly return to the centre again.
If it all checks out mechanically then you have to measure all the main voltage supplies produced by the power supply. The manual will show them all. Typically there will several such as +5 +9 perhaps a - and a + 15 and assorted display related rails such as -28 (depending on the type of display).
The very first thing to check is to confirm that when the drawer shuts, it does so fully and that any subsequent mechanical loading of the mechanism finishes. I'm not familiar with the NAD but slipping loading belts (if it uses them) can cause such problems.
There will be some form of micro switch to detect the drawer is closed. If that isn't happening then the drawer motor will keep running. So make sure that is OK.
Also check that the laser assembly is correctly positioned at the centre of the disc. It can be a useful check to manually move the pickup outward (turn the sled motor by hand with the player off) and then reconnect power and turn on. The sled should instantly return to the centre again.
If it all checks out mechanically then you have to measure all the main voltage supplies produced by the power supply. The manual will show them all. Typically there will several such as +5 +9 perhaps a - and a + 15 and assorted display related rails such as -28 (depending on the type of display).
Thanks, I've tried to ensure the tray is fully in ( tried to look for the micro switch), I've also moved the laser to the start position to no avail.
Good to know the motor waits for the laser, I've heard the laser assembly is sensitive to static so hoping that is the cause.
I'll look for the voltage,
Good to know the motor waits for the laser, I've heard the laser assembly is sensitive to static so hoping that is the cause.
I'll look for the voltage,
It could be very relevant. If the loading cycle doesn't complete then the system control will not proceed any further because the logic is effectively in a non valid state.
Mechanical issues like this are a number one cause of issues.
When the tray doesn't manage to close, can you still hear the tray motor running ?
Mechanical issues like this are a number one cause of issues.
When the tray doesn't manage to close, can you still hear the tray motor running ?
Thanks for keeping with me, when it fails to close fully on it's own (i.e about halfway), it just reopens. If I try to stop if opening/ closing then it does carries on trying to close/ open the tray, and there is a reasonable amount of force created by it (and the band seems to have a half decent grip), thats not to say it could be an issue as I've got nothing to compare it too.
It could be the belt slipping although it usually the final stage of loading that cause trouble, not just half way in.
You should be able to stall the motor by holding the tray but be careful its not good to do that for any length of time. Make a judgement call. If you can apply force and still hear the motor spin then the belt is slipping.
Beyond that and you need to see if there is any obvious obstruction... belt is most likely at this point though.
You should be able to stall the motor by holding the tray but be careful its not good to do that for any length of time. Make a judgement call. If you can apply force and still hear the motor spin then the belt is slipping.
Beyond that and you need to see if there is any obvious obstruction... belt is most likely at this point though.
Yes, its common on many players for the mechanism holding the laser and motors to lift up to meet the disc. As I say, I'm not familiar with the NAD though.
Have you tried cleaning the belt and pulleys with alcohol to see if it helps or not ?
Based on everything you have said, this would be the first thing to look at.
And although it sounds crazy, you could try with the player on its side and even held upside down to see if the mechanism then works and loads fully.
Have you tried cleaning the belt and pulleys with alcohol to see if it helps or not ?
Based on everything you have said, this would be the first thing to look at.
And although it sounds crazy, you could try with the player on its side and even held upside down to see if the mechanism then works and loads fully.
Righty!
Great news, she is working again! The cam mechanism for laser and motor that brings it up when the tray is closed had popped out. With a lot of effing and blinding I managed to get it into the right position for it to work (the gear that closes the tray and operates the cam had to be in a specific position.
Clearly as the laser/motor tray was not in the up position the device would not let it fire up.
Now to sort out the iffy open/ shut mechanism. Would it still be a case of playing round with the elastic band? Only other thoughts are it seems a little slow to seek and start up (but that could just be me).
many thanks for your perseverance!
nexts thoughts..... what about upgrading and modding it!
Great news, she is working again! The cam mechanism for laser and motor that brings it up when the tray is closed had popped out. With a lot of effing and blinding I managed to get it into the right position for it to work (the gear that closes the tray and operates the cam had to be in a specific position.
Clearly as the laser/motor tray was not in the up position the device would not let it fire up.
Now to sort out the iffy open/ shut mechanism. Would it still be a case of playing round with the elastic band? Only other thoughts are it seems a little slow to seek and start up (but that could just be me).
many thanks for your perseverance!
nexts thoughts..... what about upgrading and modding it!
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That is good news Well done.
Yes, the elastic band is a favourite. Other issues can be dirty/intermittent micro switches.
Different player but similar in operation:
Sony CDP790 and KSS240 Restoration Project
Well done.Yes, the elastic band is a favourite. Other issues can be dirty/intermittent micro switches.
Different player but similar in operation:
Sony CDP790 and KSS240 Restoration Project
Thanks, a great read, may have to have a go at some of it, definitely need to clean the circuit boards, covered in guff, and make sure all the gears are in good nick!
Not sure I'd have the confidence to adjust the setup, especially without an oscilloscope!
Most players are very similar in outline but yes, it is definitely a scope job for the electrical adjustments.
Boards generally clean up well. A good vacuum with a soft brush works well, and if there is any sticky greasy deposits or film over everything then a good wash in hot soapy water.
Post #10 (never wash transformers, motors and tiny adjustable coils (the sort with ferrite dust cores in them).
Washing an amplifier board
Boards generally clean up well. A good vacuum with a soft brush works well, and if there is any sticky greasy deposits or film over everything then a good wash in hot soapy water.
Post #10 (never wash transformers, motors and tiny adjustable coils (the sort with ferrite dust cores in them).
Washing an amplifier board
Think I may have spoken too soon!
Seems to be working fine... except at a very low volume (need to turn volume right up to hear it quietly). Volume is fine if I use a digital out (also tried different rca cables and different inputs on the amp).
Not sure if it is related by at this 'high volume' (90-95% power on the amp), you can hear a small pop when changing tracks.
Guess I could be resigned to using as a transport!?
Seems to be working fine... except at a very low volume (need to turn volume right up to hear it quietly). Volume is fine if I use a digital out (also tried different rca cables and different inputs on the amp).
Not sure if it is related by at this 'high volume' (90-95% power on the amp), you can hear a small pop when changing tracks.
Guess I could be resigned to using as a transport!?
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There are probably muting transistors on the final audio output just before it leaves for the sockets. Unlikely for both channels to be faulty though. The faint pop will be normal and caused by the muting coming into/out of operation.
Is the overall level just low, or is it non linearly low meaning loud bits are normal and quiet bits seem compressed down in level (which would be a first for me). Again, this is where a scope comes into its own. A test CD with various levels would immediately show a problem or not. You can make your own test disc using Audacity and at higher levels a good DVM would show accurate output levels which would be around 2 volts rms for a 0db test tone.
Is the amp suitable, and not one with some very low sensitivity ?
Is the overall level just low, or is it non linearly low meaning loud bits are normal and quiet bits seem compressed down in level (which would be a first for me). Again, this is where a scope comes into its own. A test CD with various levels would immediately show a problem or not. You can make your own test disc using Audacity and at higher levels a good DVM would show accurate output levels which would be around 2 volts rms for a 0db test tone.
Is the amp suitable, and not one with some very low sensitivity ?
Cheers for coming back, all the volume is low. The amp is suitable (ive had another NAD CD player plugged in one of the other RCAs, and tried this on two different sockets (originally had it plugged in the front but tried a rear when it didn't work properly).
There are four muting transistors before the sockets, as you say would be unusual for them all to have died.
As mentioned the volume it was fine using the optical out, both channels do appear to be working ok (other than the volume)
There are four muting transistors before the sockets, as you say would be unusual for them all to have died.
As mentioned the volume it was fine using the optical out, both channels do appear to be working ok (other than the volume)
Low level would be an unusual issue. If you are 100% sure that the amp behaves correctly when any other player is used then the easiest first step is just to remove (or isolate the appropriate leg) of the muting transistors in at least one channel and see if the level comes up. Worth checking the DC voltage on the control line to them as well but do it before any series base resistors.
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