classyharlan
Active Member
Thank you for the fast reply. Could you explain what you imagine could physically be happening so that such an extreme angle would be needed for playback?
Troubleshooting CD Players
- Thread starter dr*audio
- Start date
dr*audio
Fish fingers and custard!
The suspension in the mechanism could be sagging, allowing the chuck that holds the CD to rub on the supporting arm. Many newer players use cheap silicone rubber bellows instead of springs and they sag after awhile.
classyharlan
Active Member
Assuming my unit has a sagging suspension and the chuck rubbing the supporting arm, how are these remedied by my cocking the unit at a 45 degree angle in any direction? (Asking to try to get a hold on the mechanics of this.)
Hi - 1st time post here. Have a trusty working 20 year old denon setup but trying to bring to life one of my older units. Have read most of the 22 pages about this thread
Anyone remember the power up and CD load sequence for a Denon DCD-1700 ?
I have the service manuals and a variety of test gear - but the operating sequence isnt documented
In summary - a CD will load in the drawer but it doesnt spin up
This unit powers up - power rails seem OK (18V rail a bit high at 22V which may be old caps or just no drive load)
Laser and op amp supply seem solid at 5 and +-9V - low ripple
On power up without a CD laser cycles "up and then down" - is this a focus cycle ?
Drawer opens ok - limit switches appear clean and ok
Cant see any voltage demand to Spindle motor - neither op amps or motor power amp
Test mode - Laser focus cycles do not work - Laser Slide works
For this Denon - on drawer close detected - is it ....
1 - Laser focus and then CD spindle
or
2 - CD spindle then Laser focus
and
3) What stops either or both ?
Thanks - Gray
Anyone remember the power up and CD load sequence for a Denon DCD-1700 ?
I have the service manuals and a variety of test gear - but the operating sequence isnt documented
In summary - a CD will load in the drawer but it doesnt spin up
This unit powers up - power rails seem OK (18V rail a bit high at 22V which may be old caps or just no drive load)
Laser and op amp supply seem solid at 5 and +-9V - low ripple
On power up without a CD laser cycles "up and then down" - is this a focus cycle ?
Drawer opens ok - limit switches appear clean and ok
Cant see any voltage demand to Spindle motor - neither op amps or motor power amp
Test mode - Laser focus cycles do not work - Laser Slide works
For this Denon - on drawer close detected - is it ....
1 - Laser focus and then CD spindle
or
2 - CD spindle then Laser focus
and
3) What stops either or both ?
Thanks - Gray
classyharlan
Active Member
I didn't follow the advice in the top post of this thread the first time I read it because I couldn't see how it would fix my player's specific symptoms. I ended up fixing my player by following the advice in the top post of this thread. Thank you Dr. Audio.
zorandimit
New Member
Tell us how you have solved the problem. It could be useful for others.
classyharlan
Active Member
My problem was skipping CDs. I put a couple of drops of oil on the top bearing of the disk motor, which is the first suggestion in the section for skipping CDs in the top post of this thread.
I have read the sticky at the top of this thread and still need help.
Unit: Adcom GCD 600, CD changer
Symptom: Tray closes upon turning the unit on. But will not open when the OPEN button is pressed. None of the motors engage other than the tray close motor. Pressing disk skip, or track select, causes the indicator lights on the front to change in accordance with the selection but does not cause any mechanical movement. The tray will not advance to the next disk or respond to any button. The loading motor and clamping motor never engage.
Eliminated: All fuses are good and read less than .3 ohms. The roulette motor and loading motor will spin with external DC applied.
Any suggestions are greatly appreciated.
Unit: Adcom GCD 600, CD changer
Symptom: Tray closes upon turning the unit on. But will not open when the OPEN button is pressed. None of the motors engage other than the tray close motor. Pressing disk skip, or track select, causes the indicator lights on the front to change in accordance with the selection but does not cause any mechanical movement. The tray will not advance to the next disk or respond to any button. The loading motor and clamping motor never engage.
Eliminated: All fuses are good and read less than .3 ohms. The roulette motor and loading motor will spin with external DC applied.
Any suggestions are greatly appreciated.
dr*audio
Fish fingers and custard!
The Adcom changer is basically a Denon, as I recall. Remove the cover and watch what happens when the tray goes in.
Does the tray rotate?
Does the CD mechanism rise?
Does the tray rotate?
Does the CD mechanism rise?
====
With the cover removed, the tray does NOT rotate. The CD Mech does not rise. When the tray goes in, nothing else happens.
And thank you for responding.
Last edited:
@dr*audio,
I read the whole 23 pages of this topic with all your great suggestions , I checked the procedures but I still have a problem with a Sansui CD-α717DR that I bought from Japan in July:
- When it arrived it would not play and I had to replace the belt that puts the motor and the laser upwards, their technician hadn' found the problem...when checked the unit !?!
- Last month it started stopping at the mifddle of long cd' s (70 to 80 m) the sound got blurred and it stopped.
- Opened it up, cleaned and lubbed the laser guides with isoprop. alc and thin oil and it worked for some days.
- Last friday it started stopping and doing the same thing at the very first or second tracks of the cd, a commercial cd, not a burned cd r.
- I opened it again checked what I could but now when it loads the cd, the TOC comes up after a few seconds but when I press play the cd runs but it does some noises, like it is reading the cd but it does not show the track and always stops after 2m 30 s of this, showing the TOC again.
- Without the cd the laser head comes to start position and the glass goes up 3 times, I can see the beam, and goes down but doesn' t change the head position
- Lser head is a Sony KSS 152A.
This is driving me nuts and to get things worst neither the Japanese seller nor mysel have/ could find the manual or the service manual of this...
Your help would be much appreciated!
I read the whole 23 pages of this topic with all your great suggestions , I checked the procedures but I still have a problem with a Sansui CD-α717DR that I bought from Japan in July:
- When it arrived it would not play and I had to replace the belt that puts the motor and the laser upwards, their technician hadn' found the problem...when checked the unit !?!
- Last month it started stopping at the mifddle of long cd' s (70 to 80 m) the sound got blurred and it stopped.
- Opened it up, cleaned and lubbed the laser guides with isoprop. alc and thin oil and it worked for some days.
- Last friday it started stopping and doing the same thing at the very first or second tracks of the cd, a commercial cd, not a burned cd r.
- I opened it again checked what I could but now when it loads the cd, the TOC comes up after a few seconds but when I press play the cd runs but it does some noises, like it is reading the cd but it does not show the track and always stops after 2m 30 s of this, showing the TOC again.
- Without the cd the laser head comes to start position and the glass goes up 3 times, I can see the beam, and goes down but doesn' t change the head position
- Lser head is a Sony KSS 152A.
This is driving me nuts and to get things worst neither the Japanese seller nor mysel have/ could find the manual or the service manual of this...
Your help would be much appreciated!
So I disconnected the cable leading to the switch near the spindle and slide motors. As I move the gear which advances laser as part of the slide motor and mechanism, the switch closes and then if I turn the gear the other way, the switch opens. I take this to mean that the switch is fully functioning. However, it does not appear that any DC voltage ever passes to either motor. I attempted the same manual manipulation of the slide motor gear under power to see what might happen, and no DC voltage passes through to the motor regardless of whether the switch is engaged or open. I suspect I've lost an electronic component in the servo section that tells these motors to engage.
My biggest problem now is that the schematic I have is not really legible. It is in very small print and blowing it up, pixelates the numeric designation of the components. Unless I can find a better schematic, I suppose I will pull the board and see what the bottom looks like and perhaps, check a few components out of circuit. If anyone has a lead on a legible diagram for the GCD600, I would appreciate it.
Thanks to the forum for all its members do.
dr*audio
Fish fingers and custard!
In order to troubleshoot this properly you have to observe the sequence that events occur.
That's why I asked you the questions which you didn't answer.
In a 5 disc player, the sequence goes like this:
1.Put a Cd in player, push "close."
2. Drawer closes and carousel rotates.
3. some players sense the presence of Cds as the carousel rotates, some don't.
4. I all cases the carousel should stop rotating and the mechanism should raise. Does it?
5. If the mechanism raises, close the drawer with no Cd in it, and see if the mechanism raises. Does it?
6. If the mechanism raises, do you see the laser lens go up and down?
That's why I asked you the questions which you didn't answer.
In a 5 disc player, the sequence goes like this:
1.Put a Cd in player, push "close."
2. Drawer closes and carousel rotates.
3. some players sense the presence of Cds as the carousel rotates, some don't.
4. I all cases the carousel should stop rotating and the mechanism should raise. Does it?
5. If the mechanism raises, close the drawer with no Cd in it, and see if the mechanism raises. Does it?
6. If the mechanism raises, do you see the laser lens go up and down?
I think you missed my earlier post, answering your question, where I said:
With the cover removed, the tray does NOT rotate. The CD Mech does not rise. When the tray goes in, nothing else happens.
dr*audio
Fish fingers and custard!
This points to one of 2 things:
1. Power supply problem. There should be a positive and negative 12V or 15V supply for the motors, a 5V supply for the digital circuits and possibly a positive and negative supply for the analog circuitry.
2. See if there is a switch that is supposed to be triggered when the drawer is in all the way. If that switch doesn't close the micro doesn't know the drawer is in and nothing else will happen.
dclovell
Back into vinyl
I was able to pick up an Onkyo DX5500 for $25.00. It sounds and plays well except when I play a longer CD. If I play a 40 minute CD, typically no skipping. If I play a CD that is near 60 to 70 minutes it will skip intermittently. Not in the same spot and not on every track.
I have cleaned the traveler rails with a q tip and alcohol.
I have also cleaned the the laser with a qtip and alcohol.
Also when I try to close the drawer, I have to coax it shut by pushing it. Is that a belt issue? If so, does anyone have a source for a belt?
Thanks in advance.
I have cleaned the traveler rails with a q tip and alcohol.
I have also cleaned the the laser with a qtip and alcohol.
Also when I try to close the drawer, I have to coax it shut by pushing it. Is that a belt issue? If so, does anyone have a source for a belt?
Thanks in advance.
dr*audio
Fish fingers and custard!
After you clean the rails, lubricate them with a couple drops of light machine oil on either side of the pickup.
Never use alcohol on the lens, alcohol clouds some plastics.
Put a couple drops of oil on the top bearing of the disc motor.
Replace the belt. www.vintage-electronics.com is a good source. Measure the old belt and get one with a slightly smaller circumference.
dclovell
Back into vinyl
Is there an easy way to access the top bearing in the motor? The motor is under the chassis.
dr*audio
Fish fingers and custard!
Look at where the motor shaft goes into the chassis. That is the top bearing.
dr*audio
Fish fingers and custard!
I think the laser is bad. Having play problems with longer CDs is a symptom of the laserr power dropping with time. Now it won't play at all because the laser power is too low. You can confirm this by looking at the rf waveform with a scope if you have one.
The KSS-152 has not been available for years. Sorry, but you have a boat anchor.
When looking at used CD players, search for the model number and "laser" to find out what laser is used. You should only buy players that use the KSS-213 because that is what is available now, at BD Enterprises. Other lasers you get on e-bay are counterfeit junk. Liberty Electronics on e-bay also has some lasers that seem to work ok. I don't know how long they last yet, but I have gotten some KSS-210A's from them and they work.