Can you rejuvenate a crackly sounding CD Player by recapping it?

onanysunday

Listen carefully
Has anyone heard of this cdp? It is a 1984 Mitsubishi DP-205 "Medallion" cdp. I just picked it up today at the thrift store. There's just about zero information about it on the web. This thing is HEAVY and basically has a surprisingly very crisp, wide-open soundstage with lots of space in between instruments giving you the feel of expansive, three dimensional sound. It definitely sounds more natural than digitized and is easy on the ears except..there is a definite crackle or static in the background on mainly the first two tracks of a cd. Don't ask me why, but starting with the third track, the background noise lessens a bit. Strangely, the extra noise is not even on all tracks of every CD. The electrolytics definitely need replacement being over 30 years old, but I am wondering whether a recap would clean up this extra noise in the background or not..Otherwise I probably won't bother going to the trouble of trying to bring it back to its former glory.

I did a little digging and found it is almost identical to the Diatone DP-105. Is anyone familiar with either of these cd players? I believe the "Medallion" line was supposed to be TOTL Mitsubishi but feel free correct me if I'm wrong. The two main boards are sandwiched on top of one another, connected with a flexible and easily removable nylon hinge, like a book. LCD readout is bright and large and the play button has a little green play symbol that illuminates when pressed. Large transformer, Elna caps, headphone jack and Gold plated RCA jacks on the back. These are some of its better attributes. I cracked it open but couldn't readily identify the DAC, can you? I was expecting to the see the venerable PCM56P in there, but it appears to use either one or two different types of Sony DACS. Most of the chips are Sony, Toshiba and Mitsubishi.

Laser seems to read discs alright after a dry q-tip rub to remove haze/dust, although I noticed there were also a few electrolytics on the laser assembly itself that may? need replacement. Also, there are lots of laser adjustment pots on the board. Does anyone know if a laser adjustment pot might help with this particular anomaly, if so, what pot or adjustment would you make to correct this issue? If recapping would clean up the signal a bit I'd consider putting the time in as this sort of thing is a hobby of mine. Worth a recap, yea or nay?


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Here is the Diatone DP-105 for comparison. As you can see, it looks almost identical. This unit was priced at $99,800 yen in 1984 which was about $400 dollars back then.

dp-105.JPG
 
Based on it having issues only with faithfully reproducing the first few tracks on certain CDs, I am wondering if this issue mainly has to do with the laser and the couple of dried out electrolytics on the laser assembly PCB itself..anyone?
 
Has anyone heard of this cdp? It is a 1984 Mitsubishi DP-205 "Medallion" cdp. I just picked it up today at the thrift store. There's just about zero information about it on the web. This thing is HEAVY and basically has a surprisingly very crisp, wide-open soundstage with lots of space in between instruments giving you the feel of expansive, three dimensional sound. It definitely sounds more natural than digitized and is easy on the ears except..there is a definite crackle or static in the background on mainly the first two tracks of a cd. Don't ask me why, but starting with the third track, the background noise lessens a bit. Strangely, the extra noise is not even on all tracks of every CD. The electrolytics definitely need replacement being over 30 years old, but I am wondering whether a recap would clean up this extra noise in the background or not..Otherwise I probably won't bother going to the trouble of trying to bring it back to its former glory.

I did a little digging and found it is almost identical to the Diatone DP-105. Is anyone familiar with either of these cd players? I believe the "Medallion" line was supposed to be TOTL Mitsubishi but feel free correct me if I'm wrong. The two main boards are sandwiched on top of one another, connected with a flexible and easily removable nylon hinge, like a book. LCD readout is bright and large and the play button has a little green play symbol that illuminates when pressed. Large transformer, Elna caps, headphone jack and Gold plated RCA jacks on the back. These are some of its better attributes. I cracked it open but couldn't readily identify the DAC, can you? I was expecting to the see the venerable PCM56P in there, but it appears to use either one or two different types of Sony DACS. Most of the chips are Sony, Toshiba and Mitsubishi.

Laser seems to read discs alright after a dry q-tip rub to remove haze/dust, although I noticed there were also a few electrolytics on the laser assembly itself that may? need replacement. Also, there are lots of laser adjustment pots on the board. Does anyone know if a laser adjustment pot might help with this particular anomaly, if so, what pot or adjustment would you make to correct this issue? If recapping would clean up the signal a bit I'd consider putting the time in as this sort of thing is a hobby of mine. Worth a recap, yea or nay?


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I would make sure RCA posts are good and clean [toothbrush] Make sure your RCA cables are OK they go bad, A can of Dustoff does wonders for CD players , Then clean the lazer use [Google] procedures are thier, Good luck be patient
 
Thanks! Hmm. I've checked all that and everything is clean as a whistle but it still has some static that I can't seem to isolate where it's coming from. Also, all the ground wires coming off the boards on the unit are still tightly grounded to the bare chassis metal, so go figure. This is why I was considering doing a wholesale recap of the entire unit but don't want to waste my time if it isn't going to help matters.
 
I have a Harman Kardon DVD 5 that does the same thing. Still looking for a solution.
 
I'd price out what a re-cap would cost first - if it's minimal, why the hell not. I recapped a Sony CDP-302 last year and it was working perfectly fine. There is no difference in the sound, but it should have more life in it (provided the BU-1 laser doesn't call it quits).
 
Recaps usually run me around $14-20 per cd player- I don't mind the cost. It's mostly just the hours involved which I don't mind so long as I'm making an audible improvement to the sound i.e. tightening up the bass etc.. However, I am not an audio engineer and don't know (for instance) whether the audio signal is physically traveling through caps in its signal path or not, in which case it may or may not have more of an impact.. I don't work very fast because I am frequently interrupted by two small children. I do know that my recaps have generally tightened up bass boominess and the separation and clarity of instruments within a soundstage, and made the music generally more listenable with less listener fatigue on "s" sounds, sometimes but not always.. I think it may have to do with how each board's circuits are individually designed to know how it will respond to recapping. Unfortunately, I am not enough of a genius to read schematics very effectively and rely on my ears to tell me everything.

Also, I noticed older caps sound more "exciting" in certain ways. I can't say whether it is volume level or something else, but I think it may be the distortion coming through. I think distortion gets a bad rap, sometimes a little distortion can make music more lifelike and realistic sounding instead of a dry, clinical type sound you get with today's hyper-resolution recordings and playback devices. For instance, I'd still probably prefer the sound of vinyl over digital even though it's not even 16-bit in a side-by-side comparison.
 
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Forget the re-capping.

You need to carefully apply a drop of sewing machine oil to the spindle motor upper bearing (under the disc table puck)- it is dry. On the inner few tracks, the motor is spinning faster and the bearing is vibrating, resulting in the static (inability to conceal data stream loss or error correct) and, as the disc progresses, the motor slows and the vibration and consequent static noise stops.

Report your results and we will look at other measures to ensure the machine performs to the best of its ability.

You have a first generation Sony DAC, as used in the CDP-101, your machine was made mid-late 1984. Single 16 bit DAC, multiplexed L&R. Funny how the same CD players people criticized as sounding 'digital' back then, are now being re-discovered as 'natural' sounding now. :)
 
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I know it probably doesn't make sense, but I am obsessed with getting cds to sounds as close to vinyl as possible. People don't think it's possible because it's two completely separate formats (which it is) but I've been astounded just how close I can get. The older cd players get much closer to achieving this with less filtering, oversampling and using "cruder" DACs by today's standards. It's counterintuitive, you'd think it should sound worse but it ends up sounding better, more lush and realistic.
 
Forget the re-capping.

You need to carefully apply a drop of sewing machine oil to the spindle motor upper bearing (under the disc table puck)- it is dry. On the inner few tracks, the motor is spinning faster and the bearing is vibrating, resulting in the static (inability to conceal data stream loss or error correct) and, as the disc progresses, the motor slows and the vibration and consequent static noise stops.

Report your results and we will look at other measures to ensure the machine performs to the best of its ability.

You have a first generation Sony DAC, as used in the CDP-101, your machine was made mid-late 1984. Single 16 bit DAC, multiplexed L&R. Funny how the same CD players people criticized as sounding 'digital' back then, are now being re-discovered as 'natural' sounding now. :)
Thank you! I will do this first chance I get. Appreciate the tip..
 
For those of you keeping score at home, just listening to this golden combo right now is quite amazing.. Mitsubishi DP-205 cdp + Nakamichi SR-4A amp + recapped Rectilinear XII speakers + Audioquest Hyperlitz Quartz interconnects. Incredible. Level 42 - Pursuit of Accidents [made in germany] never sounded this good when compared to my treasure trove of vintage Magnavox CDB and Akai cd players.

Bright, lively, forward, open, realistic, convincing, tasty, articulate, warmth, commanding defined bass.. It's just yummy all around. In the process of securing a dbx dx5 for restoration. I've heard very good things of this very "adjustable" earlier cd player. Has anyone else had any experience with this particular model?

dbx_dx5_1.png
 
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Btw, thanks to everyone for contributing to this thread so far. It has been very engaging and fruitful for me.
 
Forget the re-capping.

You need to carefully apply a drop of sewing machine oil to the spindle motor upper bearing (under the disc table puck)- it is dry. On the inner few tracks, the motor is spinning faster and the bearing is vibrating, resulting in the static (inability to conceal data stream loss or error correct) and, as the disc progresses, the motor slows and the vibration and consequent static noise stops.

Report your results and we will look at other measures to ensure the machine performs to the best of its ability.

You have a first generation Sony DAC, as used in the CDP-101, your machine was made mid-late 1984. Single 16 bit DAC, multiplexed L&R. Funny how the same CD players people criticized as sounding 'digital' back then, are now being re-discovered as 'natural' sounding now. :)

Thanks again. I know what you mean when you talk about some of the earlier players sounding too 'digital'. I have to agree on this, I've tried giving many old Kenwoods a chance for a recap or upgrade, but I feel they weren't very good to start with and sounded a little too etched or harsh digital (to me). Then again, I am sure I've never heard their older, top models. I have an older, beautiful, heavy and compact Realistic CD-1000 (Hitachi) that doesn't sound too digitized, but the highs are a little harsh and fatiguing after a while. It could be it needs a recap, or that this is its true sonic character. In any event, you've got me thinking now.. Also, why don't you recommend replacing 30 year-old electrolytics- aren't they all out of spec at this point anyway? I can only speak for myself, but bass is noticeably tighter and better defined with a slightly lower volume after a recap. This goes for both speaker and cd player recaps from my own personal experience

You seem to know what's what, I wanted to pick your brain on something. Is there any chance that what I thought were bad, old lasers that wouldn't read that first track were actually just in need of a drop of oil to help them read the TOC and start spinning that first song? Some older player won't read that first song right away, but if you skip ahead to a later song it will read. Is that mostly because of the bearing vibrations you had mentioned earlier? If so, I don't think a lot of people have considered doing this, but if it could help rejuvenate older players to read discs again it could be worth doing to all of them, can't hurt right? I have some speed lube that is advertised for rollerblade ball-bearings, that should work right? It can't hurt to just go ahead and pre-emptively lube all those old spindles with a drop?

I've occasionally been able to get an old dysfunctional laser to read by marking, and then slightly increasing its tracking gain pot. Sometimes it appears to work forever (so far-knock on wood), other times it goes back to sporadically not reading the CDs any longer (such as in the case of that Realisitic which of course has an unobtainable laser and will become just another doorstop eventually like so many other amazing players that have stopped reading) What exactly causes the laser to "wear out" so to speak, and does replacing an old electrolytic on that little laser assembly PCB ever help it to track any better?

I want to keep my old lasers working and running as long as possible. I am convinced they can go for longer than when they present their first problem when people just give up on them and throw them away. Also, do you ever replace opamps on old boards with newer equivalents? If so, is the opamp closest to the RCA jack the most important in improving or effecting sound quality, what about all the other similarly-sized looking opamps on the all the boards with different part numbers? Are they effectively all the same and could be replaced with something like a LM4562 for instance, or could that cause more problems than any potential "enhancements". Lots of questions here (I know) but I get the impression you might have even more answers here..What are you thoughts? Thanks again!
 
CD players are complicated. There are many, many factors that interact and cause problems.

Because people don't understand them, the standard diagnosis is usually 'the laser', just like back in the day when a record wouldn't play, people would proclaim 'it needs a new needle'.

There are a few threads here on AK that are useful in diagnosing CD player problems. Do a search and have a read- plenty of very helpful techs have written much over the years.

Your description is one that I come across often, spindle motors wear, both on the upper sleeve bearing and the lower thrust plate, as well as the commutator. The fact your machine spins up, reads the TOC (table of contents) and then gives some static for the first few tracks, then is OK, is typical of a dry bearing, possibly with a bit of run-out and some light (sewing machine or similar) oil often completely solves the issue. Sometimes, the commutator is worn/dirty and a new spindle motor is in order. Sometimes the lower thrust bearing/plate is worn and the table has dropped, but that usually is a consistent issue right across the disc.

Guide rails and any rack/gear tracking parts should be cleaned and lubricated with a plastics safe grease.

Disc clamps should be inspected, cleaned and any foam/rubber clamp washers should be carefully looked at.

The laser optics should be inspected under magnification. Often, mold, fungus, dust, dirt and stuff can cause poor performance- usually at the outer edges or further into the disc. It is not just the top surface of the lens that can get crap on it. Often it is inside, under the lens or on the prisms deep inside the laser block.
If you need specifics on laser lens/optics cleaning- ask.

Unless you have a Laser Power Meter, you should never, ever, adjust the laser output pot. Seriously, it is foolish and will always result in the premature death of a laser diode. The Leader LPM-8000 is a suitable, low cost meter you can pick up easily enough.
 
Besides cleaning the outer lens, most laser assemblies I've come across appear to be permanently sealed and non-serviceable besides the old electrolytics on their outer PCB assembly. For fun I pick up lots of $10 vintage players that don't read discs. If I ever adjust a pot, I always mark them with the extremely fine line of a razor blade to keep the original setting entact if I want to revert back if the adjustment does not cause the laser to start reading. There's really no downside to it as they are usually dirt cheap and non-functional to begin with. I know there is a lens mirror on the Mitsubishi that could be dirty or hazed over, but I am still trying to figure out if there's a way I can crack into that laser assembly somehow for an inspection of the checkpoints you've mentioned. I have read through quite a few threads on CD player diagnosis and repair but most of what I have personally found is very general stuff I already know and use that doesn't dig deep enough (like your recommendation of using an LPM for instance). I still need to try your recommendation of oiling that spindle motor and will report back when I do. I'll also be checking out that LPM you've mentioned, which could be very useful- thanks.

It looks like I might need an external power source to test a laser diode unless you have a way of testing it while still connected to the cd player power supply. I don't own any fancy or expensive test equipment and am probably not going to go that route as I just don't have the extra space or budget for it. More interested in 'field adjustment' type scenarios and if that won't cut it, then I'm probably not going to invest lots of money in specialized equipment and I'm fine with that. I will however try and delve deeper into laser assemblies to try and figure out if more of these can actually be disassembled for cleaning and/or lubrication.
 
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Update: Applied a drop of oil as per restorerjohn's recommendation and it worked beautifully. Crisp audio on first track now and it leads in to Track 1 more consistently and faster. It sometimes randomly skips (VERY infrequently) and only a very small amount on pristine cds without any external vibration present, but there is a noticeably audible improvement than before. This is definitely a player worth keeping. Probably going to be looking at greasing the white, nylon plastic tray loading gears as it is a bit noisy when opening and closing, but this appears to be a gear driven mechanism as opposed to belt driven, which is probably more reliable and louder than the belt loaders I am used to and it could be normal, or it could be the noise of the drive motor itself..perhaps a drop of oil into that electric motor spindle?
 
See, that restorer-john knows his stuff! Forget the recap as it's probably not an issue.

As for getting CDs to sound like vinyl, it can be near impossible. The problem isn't the format, but the mastering. I've got some great CDs, but also some that I also have the original vinyl of. They are simply processed differently, sometimes a lot. When I digitize an LP, it sounds almost identical to the LP, often better, since I can eliminate pops and such.
 
It played discs better for a little while (when the oil was still absorbing into the spindle) then went back to not playing tracks very consistently. Worn out bearing maybe? The TOC are always read now (right away) but it hangs up trying to read that first track. I have not adjusted anything on the laser assembly. Sometimes it will start after about 10 seconds of loading, other times not. Also, I noticed all the ground wires are tightly secured to the chassis and cabinet and the entire case is slightly electrified and you get a low-level shock by touching it with the back of your hand, so there's probably a fair of EMI radiating from this thing somehow.
 
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