Hi.
I been given an old Denon DCD-595 CD player, in very good external condition. But when I load a disc there is no spindle movement, not even a jerk.
I can see the laser lens moving up and down when the tray closes.
I found a copy of the circuit, and traced the spindle drive to IC103a and the rails are good, and if I short out the op-amp inputs the motor starts to run.
I don't know much about CD player, is the unit looking for a laser signal before it spins up the disc?
Any suggests on what to check.
cheers
Nick
I been given an old Denon DCD-595 CD player, in very good external condition. But when I load a disc there is no spindle movement, not even a jerk.
I can see the laser lens moving up and down when the tray closes.
I found a copy of the circuit, and traced the spindle drive to IC103a and the rails are good, and if I short out the op-amp inputs the motor starts to run.
I don't know much about CD player, is the unit looking for a laser signal before it spins up the disc?
Any suggests on what to check.
cheers
Nick
Attachments
My parents DCD-590 had the same problem. I took the cover off had a look played with the clamping mechanism, and (whilst the power was off) gave the disk a bit of a spin.
When I powered it back on the cd spun up and correctly showed the tracks and played fine.
I don't know whether I freed up some stiction in the motor, or whether perhaps I bumped a sensor, but the issue was resolved.
Tony.
When I powered it back on the cd spun up and correctly showed the tracks and played fine.
I don't know whether I freed up some stiction in the motor, or whether perhaps I bumped a sensor, but the issue was resolved.
Tony.
Can you trace where pins 2 and 3 go to? I suspect there is a limit switch , may be on the tray mechanism, or on the door perhaps, or possibly on the clamping mechanism. Something that won't spin up the motor unless it is sure that everything is where it is supposed to be.
Does the display come up with the number of tracks etc when you spin up the motor?
Tony
Does the display come up with the number of tracks etc when you spin up the motor?
Tony
The pickup first needs to find focus on the stationary disc and only if that is achieved will the platter spin up. Its worth checking the height of the platter and making sure its not moved. Very unscientific but you can hold a CD (or bit of broken CD) close to the lens as it performs the focus search operation and fool the player into thinking its found something reflective.
50:50 it could be the pickup (is it a KSS240 or KSS210 type?). Just because there is red light present doesn't mean the laser is OK, the laser diode may just be functioning more like an LED if the diode is faulty. A laser power meter would confirm that.
Beyond that and things get heavy fault finding wise
50:50 it could be the pickup (is it a KSS240 or KSS210 type?). Just because there is red light present doesn't mean the laser is OK, the laser diode may just be functioning more like an LED if the diode is faulty. A laser power meter would confirm that.
Beyond that and things get heavy fault finding wise
Thanks Mooly.
It's a KSS240A. I've played around with a CD a different heights and there is no response from the spindle motor. So I guess the laser is duff.
I see CPC (Farnell) are setting it for £17 ex VAT.
https://cpc.farnell.com/unbranded/kss240a/cd-optical-pick-up-kss240a/dp/AS00004
is that a good price?
It's a KSS240A. I've played around with a CD a different heights and there is no response from the spindle motor. So I guess the laser is duff.
I see CPC (Farnell) are setting it for £17 ex VAT.
https://cpc.farnell.com/unbranded/kss240a/cd-optical-pick-up-kss240a/dp/AS00004
is that a good price?
Hi Nick,
Yes, it sounds like the laser may be after it's best before date. Do you havea laser power meter? If not, use the manual to measure the laser current. The new reading is listed on the paper label on the laser head. You are allowed 10% over before calling the laser dead.
Basically what is happening is that the laser is failing to lock on the CD. The disc only spins after the focus servo locks onto the surface of the disc.
KSS-240A (and 210A) laser heads. The cheap ones do not have sintered bearings where they slide on the rails. They look like copper rings around the slide rails. If the head you are looking at doesn't have these, do not buy it. It will not last very long. The rails will wear into the body of the head and cause it to "dog track" along which will jam the head. This may cause the machine to strip the teeth off the final gear where it drives the rack.
To lubricate the rails, use very fine oil with zero additives and not very much of it either. Wipe off any excess as it will only collect dust and hair. The gear rack on the head has an anti-backlash set of gears, Line them up when you put the last drive gear back in. The rack has to be clean and dry as do the teeth of the mating gear. You can use some light grease on the other gears - not very much.
Good luck on the player. Denon makes very good ones.
-Chris
Yes, it sounds like the laser may be after it's best before date. Do you havea laser power meter? If not, use the manual to measure the laser current. The new reading is listed on the paper label on the laser head. You are allowed 10% over before calling the laser dead.
Basically what is happening is that the laser is failing to lock on the CD. The disc only spins after the focus servo locks onto the surface of the disc.
KSS-240A (and 210A) laser heads. The cheap ones do not have sintered bearings where they slide on the rails. They look like copper rings around the slide rails. If the head you are looking at doesn't have these, do not buy it. It will not last very long. The rails will wear into the body of the head and cause it to "dog track" along which will jam the head. This may cause the machine to strip the teeth off the final gear where it drives the rack.
To lubricate the rails, use very fine oil with zero additives and not very much of it either. Wipe off any excess as it will only collect dust and hair. The gear rack on the head has an anti-backlash set of gears, Line them up when you put the last drive gear back in. The rack has to be clean and dry as do the teeth of the mating gear. You can use some light grease on the other gears - not very much.
Good luck on the player. Denon makes very good ones.
-Chris
Its a standard generic replacement rather than an original Sony part. A genuine Sony part is probably unobtainable these days and would be 4 or 5 times the price.
Donberg are another supplier that list the KSS240 and they say it is a 'copy part' and yet the picture shows it to have the sintered bearings (who knows on that one).
Audio Spare KSS240A (KSS 240A) - CD LASER UNIT (PICK UP) SONY COPY/LBTD159...
I always use to use a 'Special Plastics Grease' for CD work that was made by Electrolube. Its their SPG35SL grease:
https://cpc.farnell.com/electrolube...&ddkey=https:en-CPC/CPC_United_Kingdom/search
Hi Mooly,
Thank you very much for the link. I ordered a couple of those laser heads since they do have real bearings. The label on the head looks a little sketchy though. No Iop listing.
-Chris
Edit:
You know that grease is 9.79 pounds in the UK, and over here it is $22.01 CDN! I didn't think the exchange rate was that bad! They currently have 8 pcs in stock.
Thank you very much for the link. I ordered a couple of those laser heads since they do have real bearings. The label on the head looks a little sketchy though. No Iop listing.
-Chris
Edit:
You know that grease is 9.79 pounds in the UK, and over here it is $22.01 CDN! I didn't think the exchange rate was that bad! They currently have 8 pcs in stock.
It will be interesting to see what you get with those 
You just never know with generic parts unfortunately.
Donberg do some Sony grease, the type used on VCR's looks to be $120
GREASE (SGL-601/50G) SONY DSR370P from Dönberg
You just never know with generic parts unfortunately.Donberg do some Sony grease, the type used on VCR's
looks to be $120GREASE (SGL-601/50G) SONY DSR370P from Dönberg
Update..
Because of the know origin of this unit, I purchase the really cheap chinese KSS-240A. Yes, the one without the brass sleeves.
I fitted it and the disc span up, but there was a strange rubbing noise. The laser body was rubbing on the disk clamp on top of the spindle. D'oh.
So i have to get my needle files out. this fixed this issue. But still not proper operation.
The TOC is being read fine, but it will only play the first 2 tracks.
I have not touch the pots on the laser unit, but on the main board there are 2 pots labelled , F Gain and TR Gain. But I'm unable to improve on the TOC and 2 tracks.
The manual says I need reference CD CA-1094. But can't find it for sale anywhere, or any downloads. The manual is in German for it's a little hard to understand.
Maybe I damaged the cheap laser when I attacked it with a file?
After I took the original laser out, I soaked it in my ultra-sonic bath with IPA. Then let it dry out for a few hours. I refitted it, and the the disk now JERKS and stopped. Improvement, but not much. haha
Any advice welcome.
Because of the know origin of this unit, I purchase the really cheap chinese KSS-240A. Yes, the one without the brass sleeves.
I fitted it and the disc span up, but there was a strange rubbing noise. The laser body was rubbing on the disk clamp on top of the spindle. D'oh.
So i have to get my needle files out. this fixed this issue. But still not proper operation.
The TOC is being read fine, but it will only play the first 2 tracks.
I have not touch the pots on the laser unit, but on the main board there are 2 pots labelled , F Gain and TR Gain. But I'm unable to improve on the TOC and 2 tracks.
The manual says I need reference CD CA-1094. But can't find it for sale anywhere, or any downloads. The manual is in German for it's a little hard to understand.
Maybe I damaged the cheap laser when I attacked it with a file?
After I took the original laser out, I soaked it in my ultra-sonic bath with IPA. Then let it dry out for a few hours. I refitted it, and the the disk now JERKS and stopped. Improvement, but not much. haha
Any advice welcome.
I can't really visualise how the pickup could rub on the clamp tbh. Is the platter height OK.
Was it from CPC?
Reference discs are really just standard CD's made to exacting tolerances and specs and so all you need is a good commercial pressing (and red book CD). That said you can sometimes get an odd one that is poor on reflectivity but 99% are fine. The signals you see on the scope (RF or eye pattern) will look the same no matter what disc you play.
Never use a CDR or RW for any alignment procedures.
Was it from CPC?
Reference discs are really just standard CD's made to exacting tolerances and specs and so all you need is a good commercial pressing (and red book CD). That said you can sometimes get an odd one that is poor on reflectivity but 99% are fine. The signals you see on the scope (RF or eye pattern) will look the same no matter what disc you play.
Never use a CDR or RW for any alignment procedures.
Hi Mooly.
Platter was the word I was looking for. the underside of the plater has an square section and the body of the pickup is very close when in the TOC position. On the chinese pickup the body is slightly wider, and was rubbing. I guess I fightly about 0.5mm to stop it rubbing.
I didn't buy the CPC pickup, I got this from ebay for £6. haha.
Platter was the word I was looking for. the underside of the plater has an square section and the body of the pickup is very close when in the TOC position. On the chinese pickup the body is slightly wider, and was rubbing. I guess I fightly about 0.5mm to stop it rubbing.
I didn't buy the CPC pickup, I got this from ebay for £6. haha.
It looks like you might have to fork out again if you can't get the eBay special to play
Tracking gain can be set accurately by looking at the tracking error waveform (Te) with the scope time-base turned to a slow sweep speed. As the gain is increased you will see a very low frequency fundamental wave appear. Just back the gain off until this fundamental disappears.
With the focus gain adjustment you might find the pickup becomes audibly noisy (from the focus drive coils) as the gain is increased. Turn the gain down from this point. If the focus gain is to low then the player will easily lose track and skip and jump.
Always keep a watch on the RF as you alter anything.
Tracking gain can be set accurately by looking at the tracking error waveform (Te) with the scope time-base turned to a slow sweep speed. As the gain is increased you will see a very low frequency fundamental wave appear. Just back the gain off until this fundamental disappears.
With the focus gain adjustment you might find the pickup becomes audibly noisy (from the focus drive coils) as the gain is increased. Turn the gain down from this point. If the focus gain is to low then the player will easily lose track and skip and jump.
Always keep a watch on the RF as you alter anything.
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