New Laser Installed
I desoldered the ESD protection point on the new laser and proceeded to remove the old mechanism. As I was removing the six-pin plug-style power cable between the circuit board and the spindle/sled motors, I accidentally broke the Ground pin
. D'oh! An hour and a half of delicate work later, it was back in place.
I installed the pickup and a new flex cable, plugged everything back in, and put in a CD. The disc spun this time (which means I must've properly desoldered the point), however my initial problem was no better than it ever had been. This laser doesn't make the clicking noise of the other laser, though, but still no TOC. Darn.
Why wouldn't replacing the whole assembly clear up these issues? The only possible adjustment I can make now is that potentiometer on the circuit board, but since I don't know what it is, I'm hesitant to try it.
-Jameson
I desoldered the ESD protection point on the new laser and proceeded to remove the old mechanism. As I was removing the six-pin plug-style power cable between the circuit board and the spindle/sled motors, I accidentally broke the Ground pin
. D'oh! An hour and a half of delicate work later, it was back in place.I installed the pickup and a new flex cable, plugged everything back in, and put in a CD. The disc spun this time (which means I must've properly desoldered the point), however my initial problem was no better than it ever had been. This laser doesn't make the clicking noise of the other laser, though, but still no TOC. Darn.
Why wouldn't replacing the whole assembly clear up these issues? The only possible adjustment I can make now is that potentiometer on the circuit board, but since I don't know what it is, I'm hesitant to try it.
-Jameson
anatech said:
Okay, I went to the denon website and didn't see where I could order either the service manual or the test CD. Please help!
Well, the scope is a 100MHz scope, I'm assuming that's fast enough, how much hand holding does the service manual give? I'm assuming it will tell where the test points are, and what the signal should look like and what to adjust to make it match. As you can tell, I'm pretty new at this, but I'm willing to learn, follow directions well, and have somewhat of a brain. (I'm a software guy in the real world, but have an interest in hardware stuff)
Thanks for the help!
Oh, and it may actually be a DCM340, rather than the DCM440, but they should be pretty similar, I'll confirm tonight when I get home.
Hi Schaef,
Your 'scope is great. The manual will tell you what you need to know, but assumes you are trained as a technician. Therefore be aware that all service manuals omit what is considered common knowledge for their service network. That includes special knowledge particular to that brand.
Denon USA must have a 1-800 number or "contact us" email link. Use those. There may even be a parts and service email link.
-Chris
Your 'scope is great. The manual will tell you what you need to know, but assumes you are trained as a technician. Therefore be aware that all service manuals omit what is considered common knowledge for their service network. That includes special knowledge particular to that brand.
Denon USA must have a 1-800 number or "contact us" email link. Use those. There may even be a parts and service email link.
-Chris
Updates
Schaef:
Have you made any progress repairing the player? Did you buy any parts or manuals?
Chris:
A few questions...
1. How much would an oscilloscope cost that's good enough for the purpose of servicing CD players? Are there specific requirements that the 'scope must have?
2. Will any multi-meter be good enough for the task?
3. What does the test CD (ex. CA1094) have on it that a regular CD doesn't have?
I'm finally growing interested in obtaining better-than-factory settings.
-Jameson
Schaef:
Have you made any progress repairing the player? Did you buy any parts or manuals?
Chris:
A few questions...
1. How much would an oscilloscope cost that's good enough for the purpose of servicing CD players? Are there specific requirements that the 'scope must have?
2. Will any multi-meter be good enough for the task?
3. What does the test CD (ex. CA1094) have on it that a regular CD doesn't have?
I'm finally growing interested in obtaining better-than-factory settings.
-Jameson
Jameson:
I have kind of put it on the back burner for a little bit, as its not a high priority right now and I have lots of things on my plate right now. (like most people seem to have) I'm hoping to touch base on it in the next couple of months. I've also been waiting a little bit for Denon tech support to get situated in their new home, before calling and asking about the service manual. It appears that the only distributor that will actually let me look for parts doesn't have the service manual in stock for the DCM-440, so I have to talk to the tech support people.
I have kind of put it on the back burner for a little bit, as its not a high priority right now and I have lots of things on my plate right now. (like most people seem to have) I'm hoping to touch base on it in the next couple of months. I've also been waiting a little bit for Denon tech support to get situated in their new home, before calling and asking about the service manual. It appears that the only distributor that will actually let me look for parts doesn't have the service manual in stock for the DCM-440, so I have to talk to the tech support people.
Hi Jameson,
Sorry. My ISP has decided to block the auto responder from diyaudio. Found you!
A suitable 'scope would be almost any good brand, 20 MHz new models. You need 0.5 uS/div as a minimum. I haven't seen any like that without enough vertical sensitivity.
I have always found that your multimeter is one of the very most important tools. Many times you may be measuring in the mV range. Most inexpensive meters don't do this well. Some peak detect for DC and will lie outright. Fluke would be a minimum for audio service. I use both Fluke handhelds and an Agilent 34401A bench meter. They now have better ones. You can't service when your instruments don't tell you the truth. You can buy used Fluke meters on the web. Have the calibration checked at the very least. A new one will be with you for 20 years unless you kill it, good investment.
The CA1094 or equiv. are tested by Denon to have characteristics consistent with the average CD. This will affect RF pattern amplitude and waveform (how clear it is). This in turn will affect the tracking and focus servo gains, or target values if it's auto adjust. Just be glad you didn't need Philips 5 and 5A. They were $200 and $250 CDN to buy (for a shop). A very experienced technician can get by with other test discs, but will need the Denon disc to prove the machine is on spec. Warranty shops have no choice in the matter.
-Chris
Sorry. My ISP has decided to block the auto responder from diyaudio. Found you!
A suitable 'scope would be almost any good brand, 20 MHz new models. You need 0.5 uS/div as a minimum. I haven't seen any like that without enough vertical sensitivity.
I have always found that your multimeter is one of the very most important tools. Many times you may be measuring in the mV range. Most inexpensive meters don't do this well. Some peak detect for DC and will lie outright. Fluke would be a minimum for audio service. I use both Fluke handhelds and an Agilent 34401A bench meter. They now have better ones. You can't service when your instruments don't tell you the truth. You can buy used Fluke meters on the web. Have the calibration checked at the very least. A new one will be with you for 20 years unless you kill it, good investment.
The CA1094 or equiv. are tested by Denon to have characteristics consistent with the average CD. This will affect RF pattern amplitude and waveform (how clear it is). This in turn will affect the tracking and focus servo gains, or target values if it's auto adjust. Just be glad you didn't need Philips 5 and 5A. They were $200 and $250 CDN to buy (for a shop). A very experienced technician can get by with other test discs, but will need the Denon disc to prove the machine is on spec. Warranty shops have no choice in the matter.
-Chris
Chris:
Thanks for the info! I'll start looking...
Schaef:
Most of the dealers listed on Denon's Parts Distributors page [http://usa.denon.com/PartsDistributors.asp] have the service manual you're looking for listed as part DCM440S/M at a cost of ~$25.
Try searching for DCM440S/M at Tritronics Inc. They're an authorized distributor and I had good luck ordering a flex cable from them.
Hope this helps, even if you don't feel like tackling the problem now.
-Jameson
Edit: Realized partstore.com isn't an authorized Denon retailer, and that they require account creation to purchase anything.
Thanks for the info! I'll start looking...
Schaef:
Most of the dealers listed on Denon's Parts Distributors page [http://usa.denon.com/PartsDistributors.asp] have the service manual you're looking for listed as part DCM440S/M at a cost of ~$25.
Try searching for DCM440S/M at Tritronics Inc. They're an authorized distributor and I had good luck ordering a flex cable from them.
Hope this helps, even if you don't feel like tackling the problem now.
-Jameson
Edit: Realized partstore.com isn't an authorized Denon retailer, and that they require account creation to purchase anything.
mlloyd1,
Thanks for the suggestion, but I did indeed rule out that possibility. One of the first things I tried was replacing the spindle and optical assembly motors, and there was no improvement. All things considered, the problem seems to be a delicate adjustment I won't be able to make until I acquire the right equipment.
Thanks for the suggestion, but I did indeed rule out that possibility. One of the first things I tried was replacing the spindle and optical assembly motors, and there was no improvement. All things considered, the problem seems to be a delicate adjustment I won't be able to make until I acquire the right equipment.
Hi mlloyd1,
Absolutely!!
The turntable height is very important. The motor itself normally suffers bearing or brush death first. If you find a dead laser always replace the spindle motor (except for certain well made ones).
To gauge a laser head's health, you normally measure the output power or RF waveform amplitude and compare the current of the laser to the Iop value printed on the head. Sometimes the optics may have a defect that writes off the head anyway. There are some nylon heads where the supports wear out quickly (no bearing surfaces - HOP-M3).
-Chris
Yes!!!
Absolutely!!
The turntable height is very important. The motor itself normally suffers bearing or brush death first. If you find a dead laser always replace the spindle motor (except for certain well made ones).
To gauge a laser head's health, you normally measure the output power or RF waveform amplitude and compare the current of the laser to the Iop value printed on the head. Sometimes the optics may have a defect that writes off the head anyway. There are some nylon heads where the supports wear out quickly (no bearing surfaces - HOP-M3).
-Chris
Hi, Jameson,
have u solve your CD player problem?
my BADA HD21 also using Sony KSS-213C, the white button at the back is for tuning the laser head.
Last time when my laser haed read no disc, after i adjust it, it can read again... but the risk is it may shorten the life of laser if not tune properly.
but the way i now encouter a a problem, i'm not sure it is laser head die or spndle motor die... hope friend here can help.
problem aobserve:
when press play, the CD will turn clockwise, but laser head will have shi shi sound n move out then CD stop spin then the laser head will auto move in & the cd will spin in opposite direction (anti clockwise) the whole thing stop but the displat (toc) is showing the total time of the cd.
so u think is laser head die or motor die?
have u solve your CD player problem?
my BADA HD21 also using Sony KSS-213C, the white button at the back is for tuning the laser head.
Last time when my laser haed read no disc, after i adjust it, it can read again... but the risk is it may shorten the life of laser if not tune properly.
but the way i now encouter a a problem, i'm not sure it is laser head die or spndle motor die... hope friend here can help.
problem aobserve:
when press play, the CD will turn clockwise, but laser head will have shi shi sound n move out then CD stop spin then the laser head will auto move in & the cd will spin in opposite direction (anti clockwise) the whole thing stop but the displat (toc) is showing the total time of the cd.
so u think is laser head die or motor die?
Hi windwss,
The control is factory adjusted to provide the correct laser current. The diode will only emit a laser beam between a minimum current and a maximum current. Too low and it's just a weak light. Too high and the laser fails.
You can sometimes get away with increasing the laser current a little, but not if you are a tech and are charging the customer for service. The main point to consider is that a stronger beam can allow the machine to play even with another fault. So you are weakening the laser for no good reason. You should always fix the fault, not increase the laser.
Also try to type proper words and punctuation so we can read what you type more easily. There are also other adjustments that need to be made. Taking it to a good technician would be the logical course of action.
-Chris
No, it's not.
The control is factory adjusted to provide the correct laser current. The diode will only emit a laser beam between a minimum current and a maximum current. Too low and it's just a weak light. Too high and the laser fails.
You can sometimes get away with increasing the laser current a little, but not if you are a tech and are charging the customer for service. The main point to consider is that a stronger beam can allow the machine to play even with another fault. So you are weakening the laser for no good reason. You should always fix the fault, not increase the laser.
Both now that you've played with the head.
Also try to type proper words and punctuation so we can read what you type more easily. There are also other adjustments that need to be made. Taking it to a good technician would be the logical course of action.
-Chris
Hi windwss,
To check the head, look at the "eye pattern" and make sure the amplitude is high enough. Measure the laser current. You are generally allowed a 10% increase before declaring the head at it's end of it's useful life.
There are many possible faults with the head. It takes experience and some factory courses to be properly trained.
Testing the motor generally involves looking for shorted / open windings and bearing wear. I will normally remove the motor to test if I suspect a problem. If the head is bad, most motors will be shot too. Experience again is your best guide.
The service manual. Read it, then read it again. If you are still not sure, read it again until you are sure.
-Chris
To check the head, look at the "eye pattern" and make sure the amplitude is high enough. Measure the laser current. You are generally allowed a 10% increase before declaring the head at it's end of it's useful life.
There are many possible faults with the head. It takes experience and some factory courses to be properly trained.
Testing the motor generally involves looking for shorted / open windings and bearing wear. I will normally remove the motor to test if I suspect a problem. If the head is bad, most motors will be shot too. Experience again is your best guide.
The service manual. Read it, then read it again. If you are still not sure, read it again until you are sure.
-Chris