Well, increasing the gain won’t help here; the read –out needs improvement. In this particular case the slight adjustment of laser output level is required.
DENON players I repaired / modified are still running fine (one machine 3 years, the other almost 5th year) – these two are still in Sydney; the rest in Melbourne and Brisbane all serving my customers very well); all had problems reading reliably some disks. I have adjusted those using Burosch (the highest reflectivity disk I could find) for 1.8V pp. Some of DENON players failed to read some disks after only 1-2 years of use. They were marginal to start with, out of the box.
The suggested eye pattern amplitude of 1.5V pp + and – 0.3 V is within DENON specs / service manuals’ info.
I have been repairing and modifying Hi-Fi equipment since primary school… My training and education should not really be of your concern at all.
Boky
DENON players I repaired / modified are still running fine (one machine 3 years, the other almost 5th year) – these two are still in Sydney; the rest in Melbourne and Brisbane all serving my customers very well); all had problems reading reliably some disks. I have adjusted those using Burosch (the highest reflectivity disk I could find) for 1.8V pp. Some of DENON players failed to read some disks after only 1-2 years of use. They were marginal to start with, out of the box.
The suggested eye pattern amplitude of 1.5V pp + and – 0.3 V is within DENON specs / service manuals’ info.
I have been repairing and modifying Hi-Fi equipment since primary school… My training and education should not really be of your concern at all.
Boky
moamps said:
1.0V pp level is good for PORTABLE SONY CD players.
I feel sorry for you that you had to waste so many CD mechanisms...
Extreme_Boky
Don't feel sorry for me just buy them off me. 😀 😀 😀 You are apparently the only one around here who might have use for them. I had another handful of them but I donated those to my alma mater for research purposes.
I don't believe much electronics is taught in primary schools.
Regards,
Milan
I don't believe much electronics is taught in primary schools.
Regards,
Milan
Cobra2 can use one of those 10 mechanisms and adjust it as per my suggestions – the player will start reading all disks no problems. What’s the harm? The mechanisms are sitting in a corner doing nothing nevertheless…
My experience with DENON players is that anything less than 1.3V pp will render them unusable. With Burosch test disk, the reading should be around 1.8V pp. This will give good margin; the level will still be around 1.3 V pp with low reflectivity CD-R’s.
Anyhow, I will not reply to this thread any more. I have tried to help and save some money / time to fellow members. If they feel like replacing the mechanisms with brand new ones will solve their problems – fine.
Regards,
Boky
My experience with DENON players is that anything less than 1.3V pp will render them unusable. With Burosch test disk, the reading should be around 1.8V pp. This will give good margin; the level will still be around 1.3 V pp with low reflectivity CD-R’s.
Anyhow, I will not reply to this thread any more. I have tried to help and save some money / time to fellow members. If they feel like replacing the mechanisms with brand new ones will solve their problems – fine.
Regards,
Boky
I just want to say thanks for the suggestions...
But the laser-change, I always do, when I do a full service (& other mods, -but have not gotten to that stage yet with this machine).
I do the same thing when buying a secon-hand car; I always pull the engine, for a full rebuild & mods...
- cant help it...it's just in my blood.
Arne K
But the laser-change, I always do, when I do a full service (& other mods, -but have not gotten to that stage yet with this machine).
I do the same thing when buying a secon-hand car; I always pull the engine, for a full rebuild & mods...
- cant help it...it's just in my blood.
Arne K
The important point to remember is: whatever you do, do not mess with the laser current trimmer if it's new. That will rapidly reduce the life of the laser diode and if you're really unlucky, the diode will be destroyed instantaneously.
The output voltage of a RF amplifier may have values from 1 to 2V, depending on the test CD used, which is more than enough. From my experience with servicing professional Tascam CD players, the lower voltage limit is around 0.7V.
Regards,
Milan
The output voltage of a RF amplifier may have values from 1 to 2V, depending on the test CD used, which is more than enough. From my experience with servicing professional Tascam CD players, the lower voltage limit is around 0.7V.
Regards,
Milan
denon 2560
Hi Cobra2
I have a DCD 2560GL which uses the KSS210
Is yours the KSS210 too ? Have you try change the ribbon
cable on the laser unit?
Thanks
Hi Cobra2
I have a DCD 2560GL which uses the KSS210
Is yours the KSS210 too ? Have you try change the ribbon
cable on the laser unit?
Thanks
Hi ben goh,
The only laser that will work in a DCD-2560 series is a KSS-151A. It is a linear feed motor type. You must be thinking of KSS-150A which was replaced by KSS-210A. Both of which used a pair of wire cable assemblies. The KSS-240A used a flat cable which sometimes did fail. The KSS-151A cable is part of the head, not replacable.
Hi Milan,
Hi Boky,
I was trying to get your attention and help you out. I am more interested that the job is done correctly. If you charge for your work, you had better do it properly in my book. Try and study the service manual for these instead of knocking the machines. They are the same exactly in the servo department as the Sony and Tascam models that have the same mechanism. So you are knocking them as well. I suspect you are missing the tracking adjustments.
-Chris
The only laser that will work in a DCD-2560 series is a KSS-151A. It is a linear feed motor type. You must be thinking of KSS-150A which was replaced by KSS-210A. Both of which used a pair of wire cable assemblies. The KSS-240A used a flat cable which sometimes did fail. The KSS-151A cable is part of the head, not replacable.
Hi Milan,
My experience as well. CD-401 comes to mind. Nice machine. Normally other factors take these down before the head gets that bad, and the head is replaced during this service. 😉
Hi Boky,
I was trying to get your attention and help you out. I am more interested that the job is done correctly. If you charge for your work, you had better do it properly in my book. Try and study the service manual for these instead of knocking the machines. They are the same exactly in the servo department as the Sony and Tascam models that have the same mechanism. So you are knocking them as well. I suspect you are missing the tracking adjustments.
-Chris
I have asked some dudes form DENON service department to send me the service manual....
I also checked my Burosch test disk user guide.
Now, everyone should carefully read instructions from both attached files: laser drift, in particular within first couple of months of usage, is normal and sometimes it requires re-adjustment of the laser output if there’s a slight drop detected. I only ever had to replace the laser units when they COMPLETELY failed – in 80% of the time readjustment sorted out all intermittent reading problems.
Once again, you guys are wrong when it comes to RF eye-pattern adjustments.
Both user manuals state EXACTLY THE SAME specifications: Burosch: min 1.2V, DENON Service manual: nominal 1.5V pp; + and - 0.3V.
It is stupid to expect that one type of laser assembly, that comes off the factory assembly line adjusted for 1.0V pp output, will work in all CD Players!
I don't know what school / courses you guys attended.... I also feel sorry for the Service Dep. you guys work for... and for the fellow members whom you are misleading…
Boky
I also checked my Burosch test disk user guide.
Now, everyone should carefully read instructions from both attached files: laser drift, in particular within first couple of months of usage, is normal and sometimes it requires re-adjustment of the laser output if there’s a slight drop detected. I only ever had to replace the laser units when they COMPLETELY failed – in 80% of the time readjustment sorted out all intermittent reading problems.
Once again, you guys are wrong when it comes to RF eye-pattern adjustments.
Both user manuals state EXACTLY THE SAME specifications: Burosch: min 1.2V, DENON Service manual: nominal 1.5V pp; + and - 0.3V.
It is stupid to expect that one type of laser assembly, that comes off the factory assembly line adjusted for 1.0V pp output, will work in all CD Players!
I don't know what school / courses you guys attended.... I also feel sorry for the Service Dep. you guys work for... and for the fellow members whom you are misleading…
Boky
Extreme_Boky said:
In my experience, laser power begins to drop rapidly towards the end of laser life. By increasing laser diode current, we may prolong the life of the laser but not much (if the CD player is used intensively, up to 6 months at the most).
The point is, and I repeat, that it is completely unacceptable to change laser current in new, out-of-factory laser units. Now that you’ve got your hands on the Denon manual, please post the part about the procedure for readjusting laser current upon the installation of a new device. I seriously doubt you’ll be able to find a single word about that, not in your manual nor in any other service manual for that matter. There is nothing in the excerpts you posted that contradicts what I said in any way.
All laser pickups are individually tested in factories and each laser pickup contains info on its nominal laser current. On installation, we only control that the current feeding the laser diode is in the value range specified. So, your words that
demonstrate a lack of even a basic understanding of the subject.
Instead of feeling ever so sorry for people who went to school, you’d be much better off if you signed up for a couple of electronics courses yourself. Ignorance and unfounded arrogance are a deadly combination in electronics and engineering. Literally.
Regards,
Milan
Arne, does your player read the disc now ?
What exactly does it do ?
After power on show total play time and number of tracks ?
Does it read toc fast or makes noises and searches ?
On play does it show 00:00 and disc keeps spinning ? Or stops ?
If it can show total play time and number of tracks of a CDR there is no need to fiddle with laser power.
A laser that reads toc must be able to read disc somehow..
I just tried to misalign any of the 5 pots on one of my 2560s and could not get a condition where it reads toc but not plays disc.
Then I saw a couple of bipolar caps soldered together, maybe those make a problem ?
Does not look like a laser problem, more a dead IC or cap in the tracking section or missing supply voltage.
You checked both IC protectors ?
Maybe for another try put tracking offset and focus offset in middle position and tracking gain and focus gain full clockwise and the fifth pot in the middle.
What exactly does it do ?
After power on show total play time and number of tracks ?
Does it read toc fast or makes noises and searches ?
On play does it show 00:00 and disc keeps spinning ? Or stops ?
If it can show total play time and number of tracks of a CDR there is no need to fiddle with laser power.
A laser that reads toc must be able to read disc somehow..
I just tried to misalign any of the 5 pots on one of my 2560s and could not get a condition where it reads toc but not plays disc.
Then I saw a couple of bipolar caps soldered together, maybe those make a problem ?
Does not look like a laser problem, more a dead IC or cap in the tracking section or missing supply voltage.
You checked both IC protectors ?
Maybe for another try put tracking offset and focus offset in middle position and tracking gain and focus gain full clockwise and the fifth pot in the middle.
It shows only 0000 0000 0.. (no disc).
But it react to disc, and start spinning. Only some slight "search"-noise. And with some trim-adjustment, it will spin forever(?).
All IC's are getting power, as far as I can see from schematics.
Can run test-program, and it gets the 02 and 03 value.
The VR900-slead easily adjusts to 0V, (value increase when tilting machine).
I cannot get the tracking offset (VR101) to react as SM-instruction, it gives a slight amplitude-variation, but same amount (equal) on +/- side.
Arne K
But it react to disc, and start spinning. Only some slight "search"-noise. And with some trim-adjustment, it will spin forever(?).
All IC's are getting power, as far as I can see from schematics.
Can run test-program, and it gets the 02 and 03 value.
The VR900-slead easily adjusts to 0V, (value increase when tilting machine).
I cannot get the tracking offset (VR101) to react as SM-instruction, it gives a slight amplitude-variation, but same amount (equal) on +/- side.
Arne K
Cobra2 said:
I thought it does read something...
Doesn't that look like a dead part on the servo board ?
In cases like this I always test the complete transport assembly in another player and test the player with another transport to see wether it is a bad laser / connector or a bad main pcb.
There are so many sources of error, you need to know where to search.
You also could try to increase laser power on the old laser in small steps until end.
Update...
It works!!!!!!!!!!!!!!!!!!!!!!!
I have spent most of yesterday & today, resoldering...EVERY chip, transistor and connector-socket...
Changed the transistors for servo-slead, since they had been soldered/fixed/changed once before(earlier repair?).
Maybe a bad soldeing, or tired joint from heat-stretch?
Now on to the finetuning ;-)
Thanks all!!!
Arne K
It works!!!!!!!!!!!!!!!!!!!!!!!
I have spent most of yesterday & today, resoldering...EVERY chip, transistor and connector-socket...
Changed the transistors for servo-slead, since they had been soldered/fixed/changed once before(earlier repair?).
Maybe a bad soldeing, or tired joint from heat-stretch?
Now on to the finetuning ;-)
Thanks all!!!
Arne K
Hi Arne,
Way to go! You fixed it instead of patching it.
Extreme_Boky,
Your first link does not appear anywhere in the Denon manual. It is a fabrication from somewhere. The test disc specified is CA-1094 (which I have).
Right in the front of the manual it states, with zero ambiguity, that you should not under any circumstances adjust any controls on the head itself. If the chip set requires a higher amplitude, the only proper procedure is to increase the gain of the RF amp. There were some mods specifically for this with another make.
So, you are untrained, misinformed and unwilling to take good advice from trained individuals. In other words, you are dangerous on the bench.
As for the "Burosch test disk user guide", it's a little incorrect but it does clearly state that you are to read the manufacturer's service information first, and that it over rides the information they offer. I also must assume that you have misinterpreted their instructions written clearly in English. Is that your native tongue?
-Chris
Way to go! You fixed it instead of patching it.
Extreme_Boky,
Your first link does not appear anywhere in the Denon manual. It is a fabrication from somewhere. The test disc specified is CA-1094 (which I have).
Right in the front of the manual it states, with zero ambiguity, that you should not under any circumstances adjust any controls on the head itself. If the chip set requires a higher amplitude, the only proper procedure is to increase the gain of the RF amp. There were some mods specifically for this with another make.
So, you are untrained, misinformed and unwilling to take good advice from trained individuals. In other words, you are dangerous on the bench.
As for the "Burosch test disk user guide", it's a little incorrect but it does clearly state that you are to read the manufacturer's service information first, and that it over rides the information they offer. I also must assume that you have misinterpreted their instructions written clearly in English. Is that your native tongue?
-Chris
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