Please help, I'm trying to get this Denon player up running.
I have the servicemanual, but it does give me any good clue where to look for problems.
The laser is new, and measures ok on current-consumption.
It accepts a CD, starts, but will not read.
And before I can get it reading, I cant do the other adjustments.
I have tried different settings, without any improvement.
Eye-pattern looks useless, but sometimes,(a second at a time) there is a decent pattern showing. Most of the time it only shows this...(picture).
Faulty chip?
Arne K
I have the servicemanual, but it does give me any good clue where to look for problems.
The laser is new, and measures ok on current-consumption.
It accepts a CD, starts, but will not read.
And before I can get it reading, I cant do the other adjustments.
I have tried different settings, without any improvement.
Eye-pattern looks useless, but sometimes,(a second at a time) there is a decent pattern showing. Most of the time it only shows this...(picture).
Faulty chip?
Arne K
Attachments
Hi Arne,
0.2 uS/ div ? Try 0.5 uS / div for a better display. You can lower the amplitude as well.
That display is normal in the TOC area. This machine has a service mode. Read the manual and use it.
I would suspect that either the adjustments are completely wrong or the disc motor has some issues.
These are great machines when running.
-Chris
0.2 uS/ div ? Try 0.5 uS / div for a better display. You can lower the amplitude as well.
That display is normal in the TOC area. This machine has a service mode. Read the manual and use it.
I would suspect that either the adjustments are completely wrong or the disc motor has some issues.
These are great machines when running.
-Chris
Hi Arne,
Did Teac and Tascam under warranty too. I will not comment further.
The test modes should allow you to engage one servo at a time so you can tell where the problem is. You can also advance the laser assy to a data area to look at the waveform.
The later models also have a "heat run mode", this allows you to hot test an intermittent unit. When a failure occurs it will list a failure code.
It would be nice if more manufacturers installed programs like this. Is it possible there is a problem with the linear resistor that is used to determine head position?
-Chris
Did Teac and Tascam under warranty too. I will not comment further.
The test modes should allow you to engage one servo at a time so you can tell where the problem is. You can also advance the laser assy to a data area to look at the waveform.
The later models also have a "heat run mode", this allows you to hot test an intermittent unit. When a failure occurs it will list a failure code.
It would be nice if more manufacturers installed programs like this. Is it possible there is a problem with the linear resistor that is used to determine head position?
-Chris
Hi Arne,
Now that I think of it, I believe the "H" dampers got rock hard after a few years. They will cause the machine to be very sensitive to external vibration. Replace those and your machine will be much better.
-Chris
Excessive bearing wear or dead spot in a disc motor may seem fine unless you really look for it.
Now that I think of it, I believe the "H" dampers got rock hard after a few years. They will cause the machine to be very sensitive to external vibration. Replace those and your machine will be much better.
-Chris
still trying...
Disk-motor bearings seems tight, motor runs / pulls strong in both directions(!)(when mis-adjusted). Slead slides beautiful off power, pulls in nicely when powered, coils measure ok. Focus works ok.
All chip input voltages ok. It starts up, reading TOC, but does not react to it. Will not start (just focus) without disc.
Suspension is still intact.
(scoope was set to 0,2V/div - 200nS(0,2uS), using a "Burosch Laser CD test-disc. Dire Straits made no difference. Maybe I should try Rammstein).
Arne K
Disk-motor bearings seems tight, motor runs / pulls strong in both directions(!)(when mis-adjusted). Slead slides beautiful off power, pulls in nicely when powered, coils measure ok. Focus works ok.
All chip input voltages ok. It starts up, reading TOC, but does not react to it. Will not start (just focus) without disc.
Suspension is still intact.
(scoope was set to 0,2V/div - 200nS(0,2uS), using a "Burosch Laser CD test-disc. Dire Straits made no difference. Maybe I should try Rammstein).
Arne K
Hi Arne,
Your eye-pattern is only 1.1V (measured at "RF test point" - yes?) - it is too low - it should be around 1.7V peak-to-peak (I am assuming here that the Vcc of the RF chip is +5V, which is the case I think, if my memory is still serving me ok). I am familiar with that test disk as well. If you are going to use this particular test disk (which has very high reflectivity!), you can adjust the eye-pattern level to around 1.8-1.9V pp. This will give you good playability of very low-reflection disks.
As I understand, you have a brand new laser installed. Yes? If this is the case, laser "output" should be adjusted to work properly in your CD player. Sometimes they come well adjusted, sometimes they don't. From your previous post I see that you are quite good with electronics, so I'll only go as far as suggesting to do 10 degrees clockwise increments on the laser pickup pot, at the time, until you reach 1.8-1.9V pp.
The above should work fine and you'll be able to read reliably all disks.
Good luck – let us know the outcome,
Boky
Your eye-pattern is only 1.1V (measured at "RF test point" - yes?) - it is too low - it should be around 1.7V peak-to-peak (I am assuming here that the Vcc of the RF chip is +5V, which is the case I think, if my memory is still serving me ok). I am familiar with that test disk as well. If you are going to use this particular test disk (which has very high reflectivity!), you can adjust the eye-pattern level to around 1.8-1.9V pp. This will give you good playability of very low-reflection disks.
As I understand, you have a brand new laser installed. Yes? If this is the case, laser "output" should be adjusted to work properly in your CD player. Sometimes they come well adjusted, sometimes they don't. From your previous post I see that you are quite good with electronics, so I'll only go as far as suggesting to do 10 degrees clockwise increments on the laser pickup pot, at the time, until you reach 1.8-1.9V pp.
The above should work fine and you'll be able to read reliably all disks.
Good luck – let us know the outcome,
Boky
I will try to measure again, and take another pic. Pattern was taken from chip-pin...(test-point).
Laser is new. There are no laser-adjustment(other than on laser itself), but a testpoint for current, wich is 0,02mA over stamped value...(= correct+/- measuring error).
RF chip has +5,023V
Need a break, and a new box of patience
Arne K
Laser is new. There are no laser-adjustment(other than on laser itself), but a testpoint for current, wich is 0,02mA over stamped value...(= correct+/- measuring error).
RF chip has +5,023V
Need a break, and a new box of patience
Arne K
Hi Arne,
Do not under any circumstances increase the laser power. The minimum value for HF signal at the test point is 0.6 Vp-p. Your HF level seems to be normal (1.0 ~1.2 Vp-p).
Were you able to step through the service program to check each servo? (did your get a display of "03" at any point?)
I don't have the manual now, but I remember this reasonably well. Please correct me if I'm wrong. The min. RF level should be found in the section on determining if the laser is defective or not. It's just before the adjustment section.
Extreme_Boky,
What you are suggesting is irresponsible and destructive. Have you had any formal training in CD repair?
If a CD has low reflectivity, it's defective, not the laser. Don't destroy CD players due to poor media, improve the media.
-Chris
Do not under any circumstances increase the laser power. The minimum value for HF signal at the test point is 0.6 Vp-p. Your HF level seems to be normal (1.0 ~1.2 Vp-p).
Were you able to step through the service program to check each servo? (did your get a display of "03" at any point?)
I don't have the manual now, but I remember this reasonably well. Please correct me if I'm wrong. The min. RF level should be found in the section on determining if the laser is defective or not. It's just before the adjustment section.
Extreme_Boky,
What you are suggesting is irresponsible and destructive. Have you had any formal training in CD repair?
If a CD has low reflectivity, it's defective, not the laser. Don't destroy CD players due to poor media, improve the media.
-Chris
The eye pattern amplitude should be 1.5V pp + and – 0.3V.
This player will not read all disks reliably if the amplitude is below 1.5V, measured with Burosch test disk.
My suggestion to adjust amplitude to 1.8 to 1.9V (Burosch) is within the specs and will give around 1.3V pp amplitude level with low reflectivity disks. I've done this many times; DENON players in particular are sensitive to correct level adjustments!
This is not distractive – it is within the specs.
Boky
This player will not read all disks reliably if the amplitude is below 1.5V, measured with Burosch test disk.
My suggestion to adjust amplitude to 1.8 to 1.9V (Burosch) is within the specs and will give around 1.3V pp amplitude level with low reflectivity disks. I've done this many times; DENON players in particular are sensitive to correct level adjustments!
This is not distractive – it is within the specs.
Boky
Laser
I have changed about 10 of the KSS 151 or KSS 271 lasers, (most Teac and Sony machines) - I would not dream of touching the preadjusted laser-pot...
(wich just made me realize that I could have paid for a decent machine just in laser-replacements....)
I will go thru the test-program again, but last time, it only gave a "01" on the display.
Arne K
I have changed about 10 of the KSS 151 or KSS 271 lasers, (most Teac and Sony machines) - I would not dream of touching the preadjusted laser-pot...
(wich just made me realize that I could have paid for a decent machine just in laser-replacements....)
I will go thru the test-program again, but last time, it only gave a "01" on the display.
Arne K
Hi Arne,
Now, if you only got to "01", the focus servo didn't pick up the disc. This could be due to the DC offset being way off, or the focus servo output may have a failure. Either one of the transistors shorted or a fuse resistor opened. If you turn on the power, the focus coil should remain centered after possibly bouncing. Measure the voltage across the focus and tracking coils with the unit on, but stopped.
Hi Extreme_Boky,
Why do you think that? Are you looking at the manual for Denon?
I serviced Denon under warranty for many years and found them to be good at tracking CD's. The most common adjustment that was out of tolerance was the E-F balance. I would love to have one of these machines again.
-Chris
Now, if you only got to "01", the focus servo didn't pick up the disc. This could be due to the DC offset being way off, or the focus servo output may have a failure. Either one of the transistors shorted or a fuse resistor opened. If you turn on the power, the focus coil should remain centered after possibly bouncing. Measure the voltage across the focus and tracking coils with the unit on, but stopped.
Hi Extreme_Boky,
Why do you think that? Are you looking at the manual for Denon?
I serviced Denon under warranty for many years and found them to be good at tracking CD's. The most common adjustment that was out of tolerance was the E-F balance. I would love to have one of these machines again.
-Chris
Now, how difficult is to increase laser output level on ONE of those 10 transport mechanism and to give it a try?
Sony players require around 1.2V pp to work properly, AIWA around 1.3-1.4V pp. Denon at least around 1.5V pp (depending on the servo / RF “amplifier” chipset used).
You can try this simple adjustment to get SONY mechanisms to work in DENON CD players – or you could buy another 10 of these mechanisms…
I have successfully adjusted many DENON CD / DVD players to reliably read ALL cd’s – and the setting was always within the specs: 1.5V pp + and – 0.3V. The SONY’s mechanism is factory pre-adjusted to give around 1.1 to 1.2V pp.
If you stubbornly refuse to listen to my suggestion, could you maybe consider selling those 10 faulty mechanisms to me?
Thanks,
Boky
Sony players require around 1.2V pp to work properly, AIWA around 1.3-1.4V pp. Denon at least around 1.5V pp (depending on the servo / RF “amplifier” chipset used).
You can try this simple adjustment to get SONY mechanisms to work in DENON CD players – or you could buy another 10 of these mechanisms…
I have successfully adjusted many DENON CD / DVD players to reliably read ALL cd’s – and the setting was always within the specs: 1.5V pp + and – 0.3V. The SONY’s mechanism is factory pre-adjusted to give around 1.1 to 1.2V pp.
If you stubbornly refuse to listen to my suggestion, could you maybe consider selling those 10 faulty mechanisms to me?
Thanks,
Boky
Boky,
The Denon is a Sony chip set and laser. The proper RF level is about 1.0 ~ 1.2 Vp-p. Increasing the laser power will shorten the life of the laser. This only hides an imperfect alignment job.
So your repairs fail after a while and you are unaware of it.
If you do need to increase the RF level, change the RF amplifier gain instead. This is accomplished by replacing one resistor. You will make the eye pattern noisier, but at least you are not ripping off your customer(s).
You did not answer my question though. Did you ever have proper factory CD service classes? I have. On several brands including Denon.
-Chris
The Denon is a Sony chip set and laser. The proper RF level is about 1.0 ~ 1.2 Vp-p. Increasing the laser power will shorten the life of the laser. This only hides an imperfect alignment job.
So your repairs fail after a while and you are unaware of it.
If you do need to increase the RF level, change the RF amplifier gain instead. This is accomplished by replacing one resistor. You will make the eye pattern noisier, but at least you are not ripping off your customer(s).
You did not answer my question though. Did you ever have proper factory CD service classes? I have. On several brands including Denon.
-Chris
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