Sony CDP-C725 "NO DISC" error

M70AB2

M70AB2

Active Member
Hello all,

First post here. Recently I had purchased a Sony CDP-C725 CD changer for $30.00 at a local thrift store. It looked very clean and still had the stickers affixed to the front. So far, so good.

Sure enough, get it home and I then have the "NO DISC" error come up with any disc inserted, including brand-new CDs.

I have been working as an electronics technician with several industry certifications, so this doesn't worry me too much. Ordered a Service Manual from eBay as well as a new laser unit, which only set me back about another $30.00 or so. Got them both in the mail today.

Now, on occasion, I've had luck with this sort of problem on CD boom boxes merely by disconnecting the ribbon wire and then reconnecting it. Any oxidation present that would cause any resistance is scraped off by the action of disconnecting and reconnecting the ribbon wire.

With that said, I am just wondering if anyone has any experience with these units — anything I need to look out for, etc. At the point that I get this up and running, then it will get the requisite opamp, capacitor and diode mods.

But I'm definitely interested in getting this working again. I am intrigued by the DSP that is included with this unit particularly as my bonus room is rather acoustically dead. The ability to mix in a small amount of room or hall reverb is appealing, if only to gain some air or ambiance to the sound. Years ago, I attempted to use an old Ibanez SDR-1000 Digital Reverb in the system, but it made the sound rather digitized or pixelated, no doubt in part to the CD deck's digital to analog conversion and then being converted back to digital only to be converted once again to analog. Add to that the age of the SDR-1000 and that it was designed for guitar rigs and perhaps PAs.

Anyone have a Sony CDP-C725? Again, any quick fixes? Anything I need to watch out for? Any warnings? Any good modifications? Please let me know.


Thanks in advance. :music:
 
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I've got a CDP-C735, which I'd have to assume is pretty similar. The effects of the DSP functions are clearly noticeable (i.e., they're not subtle), and you may find them helpful for a room that is particularly poor acoustically, but I don't use them; for me, anyway, they muddy up the waters more than they help. But you may very well find that your case is different.

You can try cleaning the lens with isopropyl alcohol if you haven't already.

If nobody chimes in with some other helpful information soon, you might want to send a PM to dr*audio, who appears to be exceptionally well versed in CD player repair, and will almost certainly have something helpful to say.

Looking around at the Lampizator site might also be helpful to you:

http://lampizator.eu/LAMPIZATOR/CD_ALPHABETICAL.html
 
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Well, installed the new laser module and while it seems to work just fine, the motor has quit running... :sigh: Previously, it would turn the CD, but the old laser would not recognize the CD. Now it seems that the deck is trying to recognize a CD, but since the motor is not turning, it eventually cycles to the next CD station and so on.

Perhaps I knocked something loose in the process of installing the ribbon wire and assembly? The service manual is not very clear on adjusting the arm either, I have to say.

May have to PM this gentleman you mentioned.
 
possibly a power supply issue for the motor ....
scenario old motor drawing more current and never spinning ..new one using less current then power supply gives out some more .. maybe a simple dry solder joint .
 
It's the same motor. This motor spun just fine before putting the new laser module in, now it's not turning at all, alas... I wondered if I didn't seat the ribbon wire completely, but I don't think that has anything to do with the motor.

So now I'm wondering if I need to install a new motor. There's a Sony CD changer at Goodwill for $9.99 and if the motor works, maybe it'll do the trick. In the meantime, I'm going to see if there isn't something I can do to get the motor running. I'd really like to put this into my system, even if I don't use the DSP effects.
 
sorry i had assumed you changed the whole unit as that's what i generally do with cd players .
you could try and monitor the motors voltage .
 
Very interesting info. Thank you very much. I will dig into it more when I have time.

In the meantime, the laser module moves up and down as it should, but with a disc inserted, the disc now will not turn. (With the old laser module, the disc motor would spin the disc for about 20 seconds before reading "NO DISC.")

I wonder if I'd snagged the disc table and moved it somewhat, now causing this problem? Would it make sense that if the height was incorrect, that the laser would not focus correctly and then not send the message to spin the disc?

Or, does the motor start automatically? I know next to nothing about CD players, so I am curious to know if the motor starts up in response to a signal sent by the laser module, or if it operates on its own when the module, etc., moves into position.
 
M70AB2 said:
Very interesting info. Thank you very much. I will dig into it more when I have time.

In the meantime, the laser module moves up and down as it should, but with a disc inserted, the disc now will not turn. (With the old laser module, the disc motor would spin the disc for about 20 seconds before reading "NO DISC.")

I wonder if I'd snagged the disc table and moved it somewhat, now causing this problem? Would it make sense that if the height was incorrect, that the laser would not focus correctly and then not send the message to spin the disc?

Or, does the motor start automatically? I know next to nothing about CD players, so I am curious to know if the motor starts up in response to a signal sent by the laser module, or if it operates on its own when the module, etc., moves into position.
Click to expand...

This is why I said to read that thread. It explains the sequence of events that happen when you load a disc, and how to troubleshoot. I am not going to re-type it all here. I will only say that if the motor turned before, the player achieved focus lock. It then read "no disc" which either meant that the laser power was too low to read data or the adjustments may have been off. Now with the new laser, the motor doesn't turn. This could be several things. Follow the troubleshooting procedure and you will find the problem. If you bought the new laser from anywhere other than B&D Enterprises, you probably got a counterfeit part and it may not work.
 
did the new laser have a solder blob ? more often than not they have a solder blob you have to remove or a shorting clip .
 
Dr., thanks for chiming in. I only included the above information, not because I was too lazy to read the thread, but just to archive where I was at that point in time with the repair. I will also add that I include this information in the hopes that someone who has the same or similar unit and problem might be able to add some new advice. But in all sincerity, thank you again.

Johnebravo: You indicate that the DSP effects are not subtle. I assumed by the inclusion of the potentiometer for the effects, that it would be possible to mix in a very small amount of reverb. This is not the case?

In any event, I bought a Pioneer SR-9 Reverbertion Amplifier about a year ago, but never hooked it up. This unit operates on a BBD chip design and not a spring reverb pan. I suppose a main reason I bought it was for the nostalgia value — I used to pine over such out of range expensive gear when I was young and now, it was available for next to nothing. Just a fun piece of gear to have. For all I know, I may hook it up and not like it! But it does have a cool light-up display... :D
 
M70AB2 said:
Johnebravo: You indicate that the DSP effects are not subtle. I assumed by the inclusion of the potentiometer for the effects, that it would be possible to mix in a very small amount of reverb. This is not the case?
Click to expand...

No, you're right; it's possible to control the amount or extent of the effect. I never really played with it all that much, to be honest. ;) It's possible that the effects might be more appealing in a room that's not as good acoustically.
 
Yes, definitely, the bonus room is not good at all acoustically. There's a bar, neon signs here and there, carpet, speaker positioning is poor, etc. As I'd previously mentioned, years ago, I attempted to use an old Ibanez SDR-1000 Digital Reverb from an old guitar rig, but it was too grainy and pixelated.

As much as I am into guitar gear to the nth degree, I always pretty much just listened to CDs and vinyl on a "good enough" system. So for me, there's quite a learning curve still. I was reading something on this forum yesterday and I honestly did not understand just about anything being discussed. :D

But if I could get a slightly more spacious sound, all the better. Also, being a family man, I do not have unlimited funds. So maybe this'll do the trick. We'll see.
 
I have two of these. One bought new around 89-90, and another from Epay for $30 about 4-5 years ago. They both still function fully and sound very good.

I only use one, hooked directly into a DAC via toslink so the DSP function is bypassed. Before I started using a DAC, the DSP function was left in "Disco" mode with the equalizer and reverb pots centered or slightly increased. I really liked the "boost" that it gave to the sound.

Nowadays I don't use any tone controls or equalization except the "loudness" switch on my receiver. Also, now most of my digital tracks are stored on a laptop/server so these rarely get used but I keep one hooked up in case I need quick access to a CD player.

These were Sony's TOTL non ES branded changers when sold new and my original one got a lot of use. I think you will like the DSP function when you get the bugs worked out of your machine. Good Luck.
 
Well, what I ended up doing was grabbing a CDP-C735 off eBay. The seller listed it as functional and accepts returns which is good, so in for a penny, in for a pound as the saying goes. I figure I can still work on the first changer, and if I can't get it working in a reasonable amount of time, I can always keep it around for spare parts.

Got it yesterday and hooked it up. Inaugural song was "Woman from Tokyo" from Deep Purple's Who Do We Think We Are? anniversary CD.

First impression — which I must note is somewhat hobbled by the allergy-induced ear blockage and infections I am battling — is a more open sound. As a guitarist, I'm inclined to focus on the guitar and Blackmore's Strat here has a more animated and detailed sound on this changer.

I tried the EQ and DSP and they do seem to give some sort of boost, and in a pleasing way. The "DISCO" emulation is instead termed "DANCE" on the CDP-C735. I liked that particular one. When I can hear better, I'll really put it through its paces.

At some point, this will get the diode, cap and opamp mods. Maybe a few weeks down the road or so.

I still have a Pioneer A-80 that I have to restore and repair... Looks to be a blown filter cap or two and two burned 330 ohm 2w resistors, which at a glance, look to be some type of open load protection resistors. The CD changer should sound good through the A-80. Got to get to work on that...
 
dr*audio said:
The CDP-C725 uses a KSS-240 laser. It has no solder blob to remove.
Click to expand...

I just picked up one of these decks for $20. The laser info is appreciated, although the one I have works perfectly. I don't have a remote though.

I also have a Sony CDP-C69ES that was a throw in on a lot I bought in 2017. Both decks are from 1992. Can you tell me if they use the same laser assembly? The ES deck plays a CD in about 45 seconds. It starts out fine and then starts jumping ahead. Does this sound like a laser issue?
 
classic carl said:
I just picked up one of these decks for $20. The laser info is appreciated, although the one I have works perfectly. I don't have a remote though.

I also have a Sony CDP-C69ES that was a throw in on a lot I bought in 2017. Both decks are from 1992. Can you tell me if they use the same laser assembly? The ES deck plays a CD in about 45 seconds. It starts out fine and then starts jumping ahead. Does this sound like a laser issue?
Click to expand...
You would really need an oscilloscope to look at the rf waveform to be sure, but it probably is the laser. Same pickup, KSS-240.
Any Sony CD player remote will work on any Sony player.
 
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