Denon DCD-1520 CD Player Repair, Service, CD Player Adjustment & RF Eye Pattern Deep Dive!
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- Опубликовано: 12 сен 2024
- Welcome everyone, here's another video about a beautiful Denon DCD-1520 I've just repaired and that was given up as unrepairable.
Thanks to a viewer who asked if I could elaborate on the RF eye pattern stuff, I've gone into a little more detail about it here but will save a full explanation for another video.
As always, please excuse the one-take, minimal editing, and 'leave the goofs in' approach, it's the only way I can actually get videos out these days due to workload!
Hey, we've just hit one million views over at my website:
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This was highly coveted equipment back in the day and got raving reviews everywhere.
Nice to see it still getting some love...
Great restore as usual 'mate'! I owned one of these new, when it first came out and was reviewed by Ken Pholman - one of the best reviewers of higher-end gear, who could actually HEAR differences in components. The 1520 (and prior 1500 mk II) were game changers with discernible audible superiority of the time...
Thanks for the extra details about the eye diagram. I definitely appreciate the technical stuff. I'm in the category of "has the equipment and already works on equipment."
Going to get to adjusting my new to me CDP-338ESD soon, it also has the KSS-151A. I'm experienced with cassette decks but have never really dived into CD player diagnostics and adjustments, it's quite an intimidating process but it will be good to learn it.
Hi LA. I would love to see you video record the whole process, (as you say @ 13:17) from start to finish. Thank you for making and posting this video. (Nice work you do. Thank you).
It's from 1986 I had one DCD1520 andhave one MK II from 1987, difference is that II has something called Time Search. I hade the 1520 but then I got the first version of Phantome Of The Opera. The hole CD is just ONE track, no indexes nothing. So to go to a special song You hade to fast forward, then 1520 II got out, with Time Search , then You just put in the time where to skip. As fast as selecting a track.
hi
I have same player and i also had a issue with the magnet on top.. good video
I have a 1990ish DCD 1400, which was expensive enough for me then. A belt got changed years ago and it is fine. Even in dirty middle-of-NYC air. I don't know anything about electronics, can't open to do anything.. OMG it is crazy to me that good audio equipment (cassette deck, turntable, CD player) are ultimately dependent on rubber bands.
Some of the very best gear doesn't use belts but I absolutely know what you mean!
Great video, thanks!
Thank you so much for this video... !!!
CD technology is my favorite and I want to know some knowledge about it!
I have on my workbench a multimeter and 20mhz scope, but the frequency counter?
Is necessary only for PLL or other things of CD?
Thank you again :)!
Take care.
P.S Subscribed!!
Hi and glad you found it useful! A frequency counter is a really useful piece of test and measurement gear. Quality is critical with T&M gear as it relates to accuracy, this is especially important with counters. A good scope, multimeter and counter should get you going. The PLL is the main frequency related measurement that comes up in CD players, but the counter will prove useful elsewhere.
Hello Liquid Audio, I have a question if you don't mind: I own a Denon DCD 1500 CD player and recently aquired a superb vintage Marantz 2230 receiver. The receiver is in tip top condition and plays vinyl perfectly and all the inputs were tested and work fine. I proceeded to connect the denon cd player to said receiver using RCA cables into the Tape in inputs on the receiver. The cd player reads the disc and played when I pressed play. However, no sound. I can see the cd playing on the denon display but no sound coming through the speakers whatsoever. I tried the AUx input on the receiver, still no joy. I tried using headphones, nothing. By process of elimination I can say 100% that it is not a receiver issue. I don't have any other amps to test it on, so I was just wondering if I am missing something or doing something wrong? I am honestly a bit baffled by this. Thanks
It's puzzling but without the gear in front of me to test, it's hard to say. The CD player should be connected to a line level input like AUX rather than the tape input. Make sure the CD player is set to output an analog signal and that there is no digital attenuation set if this is configurable (there are a couple of DCD-1500s). Headphones can be used to verify audio is produced from the CD player if it has a socket. Beyond that, I'd say get her to a technician for further investigation.
Hi, have been looking through your videos.
Any idea for a DENON DCD685 that takes ages to read the table of contents?
Once it reads the TOC it plays the CDs without an issue, goes back and forward without hassle So I understand that is not a laser issue.
yeah in this day and age its denon but in name only
hey man thenks for the video. I have a new laser on my sega Saturn but it is not working. I guess someone before me messed up all pots on the board.The manual says adjust TE bias, Focus Gain, etc. but shows no hint on how that should be measured at. could you give me a hint or recommend something to read?? I have oscilloscope and all of thhat. Thanks
This is a tricky one because it relies on having experience with making these adjustments across many different players. The concept is the same, the execution and test points different on each machine. Service manuals are helpful so try to find and read other manuals to get a feel for the process. The manual for your machine should explain the process but if in doubt, a good technician is always the best option with anything like this.
Hi! I have a question about the eye pattern: I know that by using an analogue oscilloscope measuring the RF point and showing the eye pattern doesn’t require an outstanding equipment. But what about a digital oscilloscope? Which are the feature a digital oscilloscope should have to do such a measure? Thank you very much!
This is correct, an analog scope is great to have for jobs like this and many others. As always, the better the scope, the better the results you can achieve. My Tek digital has 'digital persistence' which is a feature that attempts to mimic the excitation behaviour of phosphor-based tubes. Triggering is also really important and how you set your trigger to yield the cleanest eye pattern. It gives me a pretty good, though not perfect result that allows me to use this scope for this digital/RF visualisation stuff that you find in CD players. Many digital scopes are useless for something like an eye pattern, the cheap ones especially so.
@@LiquidAudioI am an absolute amateur doing my own hifi if at all possible. When I rebuilt my Copland CDA-288 cdplayer to have a different mec, laser, motor and servoboard etc, I had bought that someone deemed dead, so I had to adjust the servos. So I got the digiscope out and followed procedures. I then thought why not get an analoge phosphor tube scope, and then redo the adjustments. I did and it became quite much clearer. To me at least, reading and adjusting the eye pattern, is easier using the old analogue scope. Mind you the digiscope has a lot of useful functions so I just use both. Also, some people use ISP on plastic laserlenses which gives them a haze, slowly making them not work or rather work on overtime, and then increase adjust laser power and ½ year later, it's dead. Bad quality etc... No, it was errors servicing it.
Thanks for showing.
Kind regards.
@@monzarace 100% agreed on all counts. I can only say that, whilst analog scopes are the best for looking at RF eye patterns etc, a really good digital scope can do it too, but the cheap digitals cannot. On that point, my Tek TDS3012C was over $10K AUD new. Compare that with a $300 Siglent for example and they are just in different universes. Great point about isoprop - no good for plastic and yeah, adjusting laser diode power upwards is perhaps the silliest of all things I see done on CD players. It's refreshing to see others spreading factual information rather than the bull$hit I see so often online!
2 videos in a week! We're not worthy, we're not worthy...
This is why I love my viewers - I'M not worthy!!!
Interesting video Mike, I have the very same machine, currently with the case off and the CD transport carriage out. The CD eject had stopped working, I understand from reading around that this can be due to worn belts? I am struggling to source new belts, any idea where these can be had? (tried the UK appointed rep but I guess they don't support stuff this old)
PS I am in UK
cheers
Hi Tim, yes belts are a common CD player service item. I have no suggestions for who to use in the UK unfortunately. I use commercial parts vendors, these sorts of suppliers don't supply non-trade accounts and you need to know exact sizes when ordering for example. You may find online sellers who supply kits based on knowing what the correct parts are. Failing that, you could buy a bag of belts and try for the best fit. For something like this though, I suggest a good repairer who will have all these parts in stock, as I do. They will also be able to do the other service and adjustment work that is almost always neglected or ignored but so critical to keeping your player running!
Im in RSA and specific belts are hard to get. I went to a local piping and seals supplier and got cheaply 2 things: a whole bunch of std O rings or pipe fitting seals, and some thin belting, which is essentially the belt rubber by the meter. O rings are great for cd drive mechanisms. If o rings dont fit, (but mostly you will find one that fits), for the larger belts you can then make your own belts with the belting, by gluing the right length of belting in a circle for a belt. Use a good super glue, works wonders. small amount. Suggestion, flat belting, splice at 45 deg before glueing and lightly sand off excess glue. Good luck.
What if your CD player is inoperable?
Not sure I understand the question..?
@@LiquidAudio7:17
You're right! It's best not to mess. Unless you know what your doing. I was getting hopeful watching other videos where people tweak the pots a little bit and see if the player will read the disk.
My friend and I each have a Sony SCD-777ES SACD player that doesn't read any disks.
One tip I've picked up on is the pots may oxidize over time.
@@whosonedphone OK, gotcha, yes it's absolutely best not touch a thing unless you know exactly what you are doing. The 777ES, like many other early SACD players, tends to suffer from premature death unfortunately.
Great Video thank you. Can you say something about the laser intensity adjustment? I understand that the laser output deteriorates over time, some Cd players have a small pot on the optics unit to adjust this. If this is adjusted, does it increase the eye pattern peak to peak amplitude. It would be great to know when to adjust the laser intensity and when not to, and rather adjust tracking and focus only. linked to that, what is the ideal eye pattern peak to peak voltage to strive for, with a original factory CD? 1000mV i understand?
Hi and thanks, glad you enjoyed it! Laser power output is the one thing that should generally never be adjusted. This is set at the factory by the laser manufacturer to produce the required optical power output and a particular current draw, different for each laser type. This is designed to give a good balance between lifespan and disc reading capability. It's a tradeoff. If you increase power, you decrease life. Given that disc read issues occur at end of life, increasing laser power when the laser is already on its last legs might briefly help the player read discs but then the laser really is toast and much faster than it would have died, naturally. Also keep in mind these adjustments must be done by someone with access to the right test and measurement equipment including a laser power meter, the correct test discs etc. Short answer: lasers are wearable parts and need to be replaced periodically.
@@LiquidAudio thank you so much...
@@bobof673 Don't touch the laser power. It will usually kill it fairly quickly. What happens is sometimes the suspension is sunk downwards and the servo is getting hard on overtime to try to make it read correctly. Sometimes a clog of dust is making the up/down movement hard as well. Sometimes the laser lens if plastic have been cleaned with isopropylalcohol, so gets a bad haze. Use a drop of distilled water or maybe a drop of window cleaner. Do not press down on the laser lens. It can destroy the suspension.
There's a simple formula to calculate when a laser is near it's useful life. You need to read a voltage on the player and calculate. The laserdesign is usually a burn in period, then a long, very long, lifespan where it performs the same or very near the same. Then it dies off rather quickly. That is, if other factors doesn't come in.
Cheers.
@@monzarace agreed thank you for the advice.
Since when has audio been water based?! 🤔😆
I've a Denon dn-t620 that isn't playing cds I'm assuming the pick up laser as failed wonder if its worth replacing the pick up or not
Possibly not in that case, unless it can be done very cheaply.
I have a DCD 460 I found in the neighbors trash. is it worth using? apparently it has a burr brown 16 bit dac that oversamples to 20 bit. I'm trying to figure if I should use that or an older Sony blu ray player I have, which is the bdp 350.
My DCD 460 does say double super linear converter so Im hoping it has the same setup in terms of dac just less button features which I don't need anyways.
Give it a listen and see what you think! Most dedicated CD players, even basic ones, crush DVD players sonically.
w are you, my DCD-1520 when insert cd, the main motor is not spin, is that the laser head got die?
Details in the description, and here: liquidaudio.com.au/
@@LiquidAudio it is ok can play cd now, just clean the cd driver case cable socket in the pcb is ok, i think is the bad contact cause not spin
analog scopes tend to do better for looking at the rf eye pattern
Hi Alex, correct and discussed either in this or my previous RF eye pattern video! That being said, a good digital scope like this one can do a reasonable job.
@@LiquidAudio A good digital scope in the region of $2k+ will show it nicely ;) lol. Unless you spend mega bucks on a digital scope it simply wont have the resolution to compete with an analog scope for this purpose. Nobody makes new analog scopes anymore I think?
@@alex1520 The Tek digital scope I use in the workshop is a 10K (new) scope and does a really good job, as mentioned. Wide bandwidth analog scopes are always better for these things, with CRT persistence being a big factor. No, there are no good new analog scopes, hence my collection of them which includes 7603, 2246a, 2465b etc!
Hiya, I have a Denon dcd 1520 I have had it from new, 33 years I have kept it in like New condition I still have the original box+ instructions & all. Question is it started playing up not reading the track's after say track 12+ & now it's not reading any tracks at all. Like I say the cd player is in immaculate condition no scratches anywhere any ideas as to what might be the problem. There are lasers available for the dcd 1450 1550 & 1650 would this Lazer fit the 1520.. that's if it's the Lazer of course.
Hi John, there are many potential causes of failure to read the TOC. I would need the player here for inspection, testing and diagnosis, could be the laser, may just need service like so many I see these days.
@@LiquidAudio dam... I wish you was closer unfortunately I live in the UK. Thanks for your reply.
No worries John, I'm sure there will be someone there who can assist you with this. Check with a couple of the better hi-fi stores to see who they use in your area.
Hi, I have the same problem with my 3520 described on paper at the beginning of the video. Also my 4 dampers are "worn out" and the complete drive is hanging ~5 mm lower than originally constructed. So there is some scratching noise of the drive/cd to the upper cd-holder. If I push the complete drive a few mm higher it´s gone. I would like to replace the rubber dampers, but I could not find them. Also the error report says they are not available from Denon any more. Does anyone know a similar cd-player/drive where I could find similar rubber dampers that might fit in? regards Ralph
That may be hard, so try to source something usable with the same shore and fabricate to fit. That might help.
Cheers.
A long video about "what I will you NOT show".
Denon CDPs are non-vibratory. 😀😄😆