Last night I was playing a CD and my player made a fairly loud but short crackle and then momentarily silent, after which it played clean music again.
It did this a couple of more times, each a little longer silence, then played the rest of the CD without a problem.
It sounds more like a charging spike than static and is definitely louder.
I did notice however, that when I opened the tray to eject the CD there were some mild crackles coming out of the speakers.
This morning I played a CD and everything was fine for the first half of the track and then it started to crackle loudly and for a long duration during which time there was no music. I ejected the CD and it still made crackling noises and then wouldn't read TOC.
I turned it off for half an hour and everything is fine.
I have to point out that it has an after market clock which is always powered and I did not unplug it from the mains, just the front switch.
This player is 13 years old and has only had the clock fitted, as well as replacing the two LM7805's with SKA Miniregs which necessitated replacing some of the 100uF caps around the DACs for 10uF as the Miniregs don't like to feed high capacitance apparently.
These mods have been fine for months although, since I first got this machine second hand about 6 months ago, it often acted up on bootup.
If I unplug it from the mains totally, thereby disconnecting the clock, I have several attempts to get it to read TOC and every attempt seems to have a different result.😕
Any ideas?
Thanks,
Pete
It did this a couple of more times, each a little longer silence, then played the rest of the CD without a problem.
It sounds more like a charging spike than static and is definitely louder.
I did notice however, that when I opened the tray to eject the CD there were some mild crackles coming out of the speakers.
This morning I played a CD and everything was fine for the first half of the track and then it started to crackle loudly and for a long duration during which time there was no music. I ejected the CD and it still made crackling noises and then wouldn't read TOC.
I turned it off for half an hour and everything is fine.
I have to point out that it has an after market clock which is always powered and I did not unplug it from the mains, just the front switch.
This player is 13 years old and has only had the clock fitted, as well as replacing the two LM7805's with SKA Miniregs which necessitated replacing some of the 100uF caps around the DACs for 10uF as the Miniregs don't like to feed high capacitance apparently.
These mods have been fine for months although, since I first got this machine second hand about 6 months ago, it often acted up on bootup.
If I unplug it from the mains totally, thereby disconnecting the clock, I have several attempts to get it to read TOC and every attempt seems to have a different result.😕
Any ideas?
Thanks,
Pete
Hmmm... my instincts tell me this is going to be related to the mods that have been done. While any one symptom could point to a problem in a specific area, looking at it as a whole comes down to a couple things. Crackling can/could be caused by a clock issue, guess you know whats coming next... you need to scope it to check the "quality" of the signal i.e. is it properly defined with fast rise and fall times and no spurious artifacts and also a check with a frequency counter would be a good idea to make sure its running at the correct rate. Also don't overlook the more obvious issues such as supply problems. Al rails should be checked both on a DVM and on a scope as well for noise/ripple etc.
The clock is a common denominator in all the symptoms though. Most clock mods involve simply breaking the existing clock signal path and feeding the new clock in its place. Is it possible to revert the machine easily back to standard ? which might help prove any issues.
The clock is a common denominator in all the symptoms though. Most clock mods involve simply breaking the existing clock signal path and feeding the new clock in its place. Is it possible to revert the machine easily back to standard ? which might help prove any issues.
cd problems
Thanks Mooly, I appreciate the answer.
The thing is that this player, since getting it about 6 months ago, has always been a bit "scatty" in its bootup.
It would behave differently at different times .
The Terra Firma clock made no difference to this and it gives correct voltages etc.
The only other mod has been replacing 2 7805's with SKA miniregs which give off the correct voltages and there is the correct voltage reaching the DAC's.
Today, after unplugging it to clean underneath it, it started really mucking up on bootup. Depending on how long it has been plugged in for seems to determine its behavior.
Sometimes it just comes on with no display, or it comes on with motor noise and the whole display lit up or it comes on with the drawer opening and all display with motor whining.
Other times the display is dim and nothing functions.
Whenever any of these symptoms occur, a measurement of the clock and VR's shows it's fine😡
I would have thought that if it was the clock, it would only affect its ability to read tracks?
As I was typing this, I had it plugged in and just turned it on; the drawer opened, all of the display was lit and the motor was whirring. The only button that did anything is the adjustable dither.
The voltage at the clock is 3.3v and the voltage going into the board is 2.15v.
The voltages at the DACs are at 5v. 😕
I'm wondering whether the Minireg is not reacting fast enough to the circuit being powered although its voltage is fine and it has worked well for months - as had the clock which was installed in an identical machine for a few years.
If you need to see a schematic, I can email a PDF.
Regards,
Pete???
Thanks Mooly, I appreciate the answer.
The thing is that this player, since getting it about 6 months ago, has always been a bit "scatty" in its bootup.
It would behave differently at different times .
The Terra Firma clock made no difference to this and it gives correct voltages etc.
The only other mod has been replacing 2 7805's with SKA miniregs which give off the correct voltages and there is the correct voltage reaching the DAC's.
Today, after unplugging it to clean underneath it, it started really mucking up on bootup. Depending on how long it has been plugged in for seems to determine its behavior.
Sometimes it just comes on with no display, or it comes on with motor noise and the whole display lit up or it comes on with the drawer opening and all display with motor whining.
Other times the display is dim and nothing functions.
Whenever any of these symptoms occur, a measurement of the clock and VR's shows it's fine😡
I would have thought that if it was the clock, it would only affect its ability to read tracks?
As I was typing this, I had it plugged in and just turned it on; the drawer opened, all of the display was lit and the motor was whirring. The only button that did anything is the adjustable dither.
The voltage at the clock is 3.3v and the voltage going into the board is 2.15v.
The voltages at the DACs are at 5v. 😕
I'm wondering whether the Minireg is not reacting fast enough to the circuit being powered although its voltage is fine and it has worked well for months - as had the clock which was installed in an identical machine for a few years.
If you need to see a schematic, I can email a PDF.
Regards,
Pete???
This is where it gets difficult you see. You need more than just DVM readings. One very real problem with digital circuitry (and this may be relevant given the inconsistent behaviour it exhibits) is something called a "race hazard situation" where various voltage rails don't rise in the correct order and at the correct rate. When that happens the logic can be in an unpredictable and indeterminate state. This is where a modified player is an unknown because it now doesn't conform to the original design. Even if the clock proved OK you are still left with the question of whether it actually starts at approximately the correct time and whether the logic resets correctly. Once circuitry and PSU's are modded all that becomes a big question mark 🙂
The symptom of a motor spinning at power up and the display misbehaving again point to the clock as a common denominator. The clock can be used a master signal for various parts of the system control and so on. If that fails then the uP (main microprocessor) is out of step with all that's going on and the machine locks up unpredictably.
The symptom of a motor spinning at power up and the display misbehaving again point to the clock as a common denominator. The clock can be used a master signal for various parts of the system control and so on. If that fails then the uP (main microprocessor) is out of step with all that's going on and the machine locks up unpredictably.
Thanks Mooly,
I'll try to refit the original crystal and see what happens. But that won't be for another couple of days.
Is there anyway of resetting the logic because it's the logic I have suspected- although I am certainly no technician.
I still can't understand that the clock could be a problem seeing as it is always powered up, even when the machine is off at the front switch😕
Sorry, I have to go to bed now and get some sorely needed beauty sleep.
If you have any further ideas, please let me know and I'll be back on in the morning.
Regards and thanks,
Pete
I'll try to refit the original crystal and see what happens. But that won't be for another couple of days.
Is there anyway of resetting the logic because it's the logic I have suspected- although I am certainly no technician.
I still can't understand that the clock could be a problem seeing as it is always powered up, even when the machine is off at the front switch😕
Sorry, I have to go to bed now and get some sorely needed beauty sleep.
If you have any further ideas, please let me know and I'll be back on in the morning.
Regards and thanks,
Pete
The logic gets reset at every "hard" (mains power connect) switch on. The front switch may be a standby only function that doesn't fully power down all the circuitry.
This is why I say there are so many unknowns. For example, if the clock is always present then that may (not for certain but may) be an invalid condition for the relevant IC's that the clock feeds. If the clock is present when the rest of the machine is powered down then the clock could easily partially power up the IC (via internal junctions within the IC's) and cause some problem.
This is why I say there are so many unknowns. For example, if the clock is always present then that may (not for certain but may) be an invalid condition for the relevant IC's that the clock feeds. If the clock is present when the rest of the machine is powered down then the clock could easily partially power up the IC (via internal junctions within the IC's) and cause some problem.
Hi Mooly,
thanks for the further reply.
I forgot to say that it is a Rotel RCD991AE if you need to look at schematics, and the clock has its own power transformer and it only powers the clock, according to the supplier .
Because it has a couple of 1 farad caps as supply caps, it has a delay switch so as there is more voltage applied initially (as I understand it) and then, after about 10-15 minutes the front switch is turned on and the delay switch is moved to the run position.
This allows the clock to reach full voltage before boot up.
Interestingly, tonight, I plugged in the power and immediately flicked the switch after I turned it on at the front, and it worked.
Of course, it didn't work when I put it back where it lives😡. I'll try to refine my technique for now.
The other question is regarding the regulators.
Initially, the player had 100uF caps around the DACs; Greg, who makes the Minireg said that they don't like much capacitance after them and I changed all of the supply caps around the DACs to the suggested 10uF.
Is it possible that the player itself doesn't like the low capacitance around the DAC supply caps?
Thanks for any further info,
Pete
thanks for the further reply.
I forgot to say that it is a Rotel RCD991AE if you need to look at schematics, and the clock has its own power transformer and it only powers the clock, according to the supplier .
Because it has a couple of 1 farad caps as supply caps, it has a delay switch so as there is more voltage applied initially (as I understand it) and then, after about 10-15 minutes the front switch is turned on and the delay switch is moved to the run position.
This allows the clock to reach full voltage before boot up.
Interestingly, tonight, I plugged in the power and immediately flicked the switch after I turned it on at the front, and it worked.
Of course, it didn't work when I put it back where it lives😡. I'll try to refine my technique for now.
The other question is regarding the regulators.
Initially, the player had 100uF caps around the DACs; Greg, who makes the Minireg said that they don't like much capacitance after them and I changed all of the supply caps around the DACs to the suggested 10uF.
Is it possible that the player itself doesn't like the low capacitance around the DAC supply caps?
Thanks for any further info,
Pete
I'm looking at an RCD991 circuit now and the mains (power switch) operates directly on the primary of the tranny so it kills all supplies in its standard form.
So all these changes such as the regs, the cap changes, the 1 farad (1farad !!) caps and this delay circuit must all be part of the mods.
With the greatest respect to all those involved in the mods, it really sounds to me as though those mods are the root cause of the problem. There are too many unknowns and too many major changes away from the original spec to guess at what may be wrong.
When you say you powered up and flicked the switch... that points again to a logic issue, things appearing/resetting in the wrong order.
Do you see 🙂
So all these changes such as the regs, the cap changes, the 1 farad (1farad !!) caps and this delay circuit must all be part of the mods.
With the greatest respect to all those involved in the mods, it really sounds to me as though those mods are the root cause of the problem. There are too many unknowns and too many major changes away from the original spec to guess at what may be wrong.
When you say you powered up and flicked the switch... that points again to a logic issue, things appearing/resetting in the wrong order.
Do you see 🙂
if your clock powers up a little too late they player gets "confused" and reacts as if there is no clock signal.
😎
😎
Thanks again, Mooly.
I'll try one thing at a time.
Firstly, I'll change back to the crystal oscillator and see what that does.
Unfortunately, I have to use the original one out of this machine, rather than the custom made crystal fitted to my original machine (the subject of previous posts 😀) which was removed from it by the guy who fitted the clock to my first machine. There was never an issue then and it was I who swapped it over to my newer machine a few moths ago but there didn't seem to be any issues then.
Likewise, those Miniregs are truly great, but I am not equipped with a scope or the knowledge to use one.
At the moment, I have it playing and that was achieved by plugging it in and immediately switching on the front switch, so I'll leave it for now.
I will be taking it down to Joe who makes the clock in order for him to stick his oscilloscope on it and we'll see if we can get it to boot up and maybe find out what is wrong.
In the meantime, if you hear from the person I was trying to contact, would you please pass on a message.
I will keep you posted.
Regards and thanks,
Pete
I'll try one thing at a time.
Firstly, I'll change back to the crystal oscillator and see what that does.
Unfortunately, I have to use the original one out of this machine, rather than the custom made crystal fitted to my original machine (the subject of previous posts 😀) which was removed from it by the guy who fitted the clock to my first machine. There was never an issue then and it was I who swapped it over to my newer machine a few moths ago but there didn't seem to be any issues then.
Likewise, those Miniregs are truly great, but I am not equipped with a scope or the knowledge to use one.
At the moment, I have it playing and that was achieved by plugging it in and immediately switching on the front switch, so I'll leave it for now.
I will be taking it down to Joe who makes the clock in order for him to stick his oscilloscope on it and we'll see if we can get it to boot up and maybe find out what is wrong.
In the meantime, if you hear from the person I was trying to contact, would you please pass on a message.
I will keep you posted.
Regards and thanks,
Pete
Your welcome 🙂 I knew this one would be an uphill problem 😀
Anyhow, to revert back to the original oscillator you must undo some of the changes that will almost certainly have been made. Typically that would be refitting the crystal and any small caps that go to the crystal. You also need to check/reinstate the original supply to the oscillator. The aftermarket clock will have had its output fed into the chain somewhere. You need to remove that and reinstate any path that the original signal takes and might have been broken with the mod.
How is the clock signal (and as important) its return wired to the board, have you got two wires?
Thanks yet again.
You are a great help.
The original oscillator and the two caps around it were removed but the outboard clock is connected to one of the removed capacitors positions (C211), so no power feed was broken.
Just to clarify, the clock has its own separate transformer and it has the large (2x 1 farad) caps on board as is the delay circuit with a separate switch to deactivate (?) it. There is then a separate module with the tentlabs oscillator and a couple of small components on it which is mounted very close to the original crystal position.
I can email you a couple of photos if it helps (due to the fact that I had set up a photobucket account and couldn't remember my password!!
)
Regards,
Pete
You are a great help.
The original oscillator and the two caps around it were removed but the outboard clock is connected to one of the removed capacitors positions (C211), so no power feed was broken.
Just to clarify, the clock has its own separate transformer and it has the large (2x 1 farad) caps on board as is the delay circuit with a separate switch to deactivate (?) it. There is then a separate module with the tentlabs oscillator and a couple of small components on it which is mounted very close to the original crystal position.
I can email you a couple of photos if it helps (due to the fact that I had set up a photobucket account and couldn't remember my password!!
)Regards,
Pete
Hi thanks Marce,
we must have cross posted so your answer is in my last post.
Thanks anyway, much appreciated,
Pete
OK, that makes sense. The oscillator was being fed into the input of the first gate. Make sure the two resistors and two caps are fitted correctly. You can post the pictures on the forum if you want 🙂 but its one of those things where you really need to have it in front of you to examine.
Attachments
Thanks Mooly.
I haven't had a chance to take it apart but something interesting happened the other night.
After leaving it for a while, I plugged in the power and turned on the front switch after about 30 seconds.
This resulted in bootup, so I inserted a cd and it played well.
Just after the cd started playing I flicked the delay switch to its normal operating position and got the exact crackling and silence as described in my first post.
I flicked the switch back to its delay position and the problem disappeared.
I kept the switch on this position for a few days and then flicked it to its run position with no ill effect.
It seems like it just plays up when the clock is not fully charged but it plays fine???
I have not had the guts to turn it off at the front switch or certainly unplug it at the rear.
The power supply to this clock has a LM317 and I replaced it with an LM338 a while ago as I found that they sounded much better in my Teddy Regs - is there any reason why this would cause it any grief?
They are supposed to be a drop in replacement but I'm wondering whether there is some parameter that the clock doesn't like?
On the other hand, seeing as it does seem to be power related; is there a possibility of a dry joint?
I swapped out all of the electrolytics in it for KZ Muse after the first few issues but nothing changed - other than the sound improved😀
I hope to get a chance at it on the weekend.
Regards,
Pete
I haven't had a chance to take it apart but something interesting happened the other night.
After leaving it for a while, I plugged in the power and turned on the front switch after about 30 seconds.
This resulted in bootup, so I inserted a cd and it played well.
Just after the cd started playing I flicked the delay switch to its normal operating position and got the exact crackling and silence as described in my first post.
I flicked the switch back to its delay position and the problem disappeared.
I kept the switch on this position for a few days and then flicked it to its run position with no ill effect.
It seems like it just plays up when the clock is not fully charged but it plays fine???
I have not had the guts to turn it off at the front switch or certainly unplug it at the rear.
The power supply to this clock has a LM317 and I replaced it with an LM338 a while ago as I found that they sounded much better in my Teddy Regs - is there any reason why this would cause it any grief?
They are supposed to be a drop in replacement but I'm wondering whether there is some parameter that the clock doesn't like?
On the other hand, seeing as it does seem to be power related; is there a possibility of a dry joint?
I swapped out all of the electrolytics in it for KZ Muse after the first few issues but nothing changed - other than the sound improved😀
I hope to get a chance at it on the weekend.
Regards,
Pete
I don't think its a dry. My money is still on the mods that I think are going to be "flawed". I don't think you'll find a faulty part or anything like that. It all comes down to the way the whole machine is powered and the sequencing of the various clock signals.
If the clock is present when the rest of the machine is off then to me that is a no no because the clock signal has the ability to transfer charge into the rest of the unpowered circuitry causing potential problems at start up. That clock signal is almost like a battery and allows various parts of the circuitry to be "backfed" and to assume non valid voltage that are already present when you switch on. Logic circuitry needs very exact and defined conditions.
I know that's not what you want to hear... but that is still my feeling on it all.
If the clock is present when the rest of the machine is off then to me that is a no no because the clock signal has the ability to transfer charge into the rest of the unpowered circuitry causing potential problems at start up. That clock signal is almost like a battery and allows various parts of the circuitry to be "backfed" and to assume non valid voltage that are already present when you switch on. Logic circuitry needs very exact and defined conditions.
I know that's not what you want to hear... but that is still my feeling on it all.
Thanks Mooly, this clock has worked fine for years in an identical machine so I can only assume that it is something to do with the Regulators or the associated reduced capacitance around the DAC chips.
I'll try your suggestion first and stick the crystal and caps back in and see what happens.
Regards,
Pete
I'll try your suggestion first and stick the crystal and caps back in and see what happens.
Regards,
Pete
Thanks again, Mooly.
I'll try to get around to dropping in the old crystal, but I just checked and found that the old machine, in which the clock operated flawlessly for years, did not have the resistors you circled, removed.
Perhaps, if what I think you are saying is a potential problem, I should lift one end of them in order to isolate any "battery" issue?
Regards,
Pete
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