Music Centre playing up

[Lucky Luke]

Hello, experts. I have a fairly old music centre. The problem I have is with playing CD discs on it. When this Dawoo music centre was bought (eleven years ago), it would play discs with no trouble at all, and this state of things lasted for several years. Then there came a time when, in order to play a CD, it was necessary to take the top of the case off it and partly dismantle the rotation mechanism, in order to get at the lens. I would carefully clean this lens, and the machine would then play a CD with no trouble at all. However, after only about a week of non-use, the same trouble would occur.

Finally, I found out that a likely cause of its malfunctioning was static electricity, which may have attracted dust onto the lens. So, using a spray-can of anti-static solution, I took the top off again etc., and blasted the lens with anti-static. I also blasted the cleaning cloth for the discs, with this spray. The machine worked OK for a few weeks, while I did occasional tests after a period of non-use (about two weeks of non-use). The machine worked each time it was tested, but only after the CD had been warmed in front of the gas fire for several seconds. Mostly, the player was left alone, as we do not often listen to music (not on this machine, anyway).

After about three months of non-use, and being in the mood for music we have stored, I tried to play a disc. I carefully warmed the CD with the gas heater, as I had learned to do as a condition of it playing. Now, the familiar message showed on the display: CD error.

Yet, any CD that I choose can be put into our DVD recorder (which also will play CDs, but not as satisfactorily as the music centre — when it works), and it will play straight away and without any warming being required. As a test, I have even played a CD in the DVD recorder as described, then put the same disc into the CD player, which refuses to recognise it. It would seem, therefore, that the CDs ought not to need any warming, even though my experience with the music centre seemed to suggest otherwise.

My question is this: since, after this machine was bought, we enjoyed a period of about three years (and, possibly, much longer than this) with no trouble, why can we not now leave the machine for long periods after applying anti-static (since, when the machine was relatively new, we were able to do this — and without applying antistatic) and still get it to play without first tinkering with it?

Thanks in advance for any helpful responses.

A.W.

 

[DaveHerns]

11 year old Daewoo stereo is not worth repairing .Sorry

 

[Lucid]

"Dawoo....... bought (eleven years ago) .... dust onto the lens ... blasted the lens with anti-static .... music we have stored"


I take my hat off to you for persevering so long and going to some quite extraordinary lengths by the sound of it. Daewoo isn't a manufacturer I'd readily associate with audio product. I know it better from TV, video, white goods and cars before the sell out to GM. It was one of the big four S. Korean chaebols before its collapse in 1999.

Dust on the lens is a small issue. The more common problems are either a gradual failure of the laser diode (i.e. a weakening laser) or some issue with the laser focus mechanism. For the former you'll often find that home burned discs are the first to start playing up because they reflect less light than pukka commercial discs. (I notice you wrote "music we have stored" Does that mean you have lots of home burned discs?) The latter could be caused by some issue with the servo mechanism that controls the laser focus and tracking. Since the servo uses the laser signal level bouncing off the disc to help it track the data channel then either a failing servo or a failing laser diode would contribute to the error. BTW, did you that a CD data channel is 2000 times finer than the average human hair! The reason for mentioning that is it's not something that can be easily adjusted as a permanent fix. For those products where it's worth it in parts and labour costs then the answer is usually to replace the complete laser mechanism.

I can't say specifically why warming the discs would cause them to play other than perhaps it changed the refractive index of the polycarbonate just enough to increase the reflectivity to a tolerable level. DVD/CD players and DVD recorders have lenses that can focus on much finer pits than used in CDs. The laser capabilities and range over which the servos are needed to work would require higher precision optronics.

The prognosis for your Daewoo stereo isn't good I'm afraid. Perhaps it's time to give the old girl a rest and look to pastures new?

 

[Lucky Luke]

Lucid (also, DaveHerns): Thanks for your replies. I will accept your diagnoses, and replace the music centre. I don't mind doing this now, seeing that, from what you tell me, it is necessary. In my ignorance, I was just clinging on to a hope that a bit more information would enable me to get the machine working again, that's all. One would think that you get what you pay for. However, before buying the Dawoo (which was not expensive), I had paid what seemed to be a lot of money for a Sony, which gave nothing but trouble. That's why I got rid of it when it had not been used for very long (about nine months, when we were listening to much more music than we do now). The Sony was also the reason for my not being willing to spend a heap of money on a replacement.

As you suggest, Lucid, much of our music is what I have burned onto my own cds. However, even commercially recorded cds have not being playing, either. Thanks indeed for the information you have given about laser diodes etc.
Best regards to you both,
A.W.

 

[Lucid]

I can sympathise with you over the Sony. In my experience Sony used to make some decent separates back in the 80's and early 90's, but their all-in-one systems were rarely anything worth writing home about despite the Sony "premium" price tag. To counter that though Aiwa, which was part owned by Sony, moved from producing mainly cassette decks and portable tape players to introducing a range of micro Hi-Fi systems in the late 80's. I bought one for the father-in-law. It was a bit more costly than competing products but has proved its worth. It has only just been replaced this year some 25+ years later. The system still played fine after all these years. The issue was a worn loading mechanism which eventually made it impossible to open the disc tray reliably.

What's interesting is the relative cost when adjusted for inflation. I was in the retail trade back in '89, and at trade price the Aiwa was around £115 at cost back then. That's the equivalent of a shade over £250 in today's money when adjusted for inflation. I look at what masquerades for small Hi-Fi systems today and see branded product from well-known Japanese brands that has a similar specification on paper to the old Aiwa and yet they sell for under £80 retail. So somewhere in the last quarter century they've been able to make £200+ worth of economies in manufacturing and that despite rising raw materials costs etc. Is it any wonder things don't last?

Back in July I helped my F-in-L replace the Aiwa. He was going to go to Currys or Costco and just buy an all-in-one off the shelf for around £150. That would have made me quite angry; not with him, but with the state of retail trade. Maybe I'm unusual in coming from a background where as store assistants we were expected to listen to and interpret customer needs and then make recommendations. It seems to me that since the demise of the smaller retail stores and the expansion of internet retailing that much of this skill has been thrown away in the quest for "cheap" and "quick". Anyway, back to the F-in-L I took him to a national AV retailer's store and I conducted a dem for him of what could be done at a couple of different price points. We walked out with a Denon (DM39DAB) and a pair of Q Acoustic speakers. The total spent was around £280. I picked up and refurb'ed a pair of used speaker stands. The jump in sound quality compared to the Aiwa is marked. It's a massive step forward. Manufacturing economies do work, but IMO they only come in to force above a certain threshold.

If you're looking to replace the Daewoo and are open to alternatives where you'd get far better performance and (possibly) much longer life too, then I'd definitely recommend looking at used equipment. Now is a particularly good time to strike because there are strong signs that the market is starting to dry up. By that I mean that a greater proportion of people have been buying speaker docks over the last 10 years and so fewer decent Hi-Fi systems have been sold. That means a shortage of those decent Hi-Fis coming on to the used market now, and the situation is only going to get worse. I'm seeing prices rise for decent used gear, and people asking silly or unjustified prices for low performance gear that wouldn't have got any attention a couple of years ago.

As well as Ebay there are other places to look for good used gear. Gumtree is one such place. Here's a selection of ads from up and down the country that caught my eye. My criteria was to keep the total spend under £120, and to avoid anything where the failure of one component would render the entire system useless, and the gear had to be capable of outclassing anything you might buy retail in the £200-£300 price bracket. In some cases you'd have to spend £600-£800 new to match the performance.

Complete solutions:

Tibo hifi dab - Heywood, Manchester

Technics HD-560 Stereo System - Birmingham and Walsall

Denon/Cambridge Audio/Gale - Willowbrae, Edinburgh



Mix-n-Match:

ARISTON TUNER, NAD 3020 AMP, SANSUI CD PLAYER - Sheffield, South Yorkshire

KEF C10 Bookshelf HI-FI Speakers - Dartford, Kent

Tannoy Mercury F4 Custom Floorstanding Speakers - Norwood, London

KEF loudspeakers - Shoreditch, London

 

[Lucky Luke]

Lucid: Once again, your comments, advice, and the trouble in researching that you have taken, are very much appreciated. I shall now have to consider all that you say (and discuss it with my better half). It's more than likely that what you have said has saved me from making a costly mistake. People like me are just sheep to the slaughter!
A.W.

 

[Lucky Luke]

If you're looking to replace the Daewoo and are open to alternatives where you'd get far better performance and (possibly) much longer life too, then I'd definitely recommend looking at used equipment. Now is a particularly good time to strike because there are strong signs that the market is starting to dry up. By that I mean that a greater proportion of people have been buying speaker docks over the last 10 years and so fewer decent Hi-Fi systems have been sold. That means a shortage of those decent Hi-Fis coming on to the used market now, and the situation is only going to get worse. I'm seeing prices rise for decent used gear, and people asking silly or unjustified prices for low performance gear that wouldn't have got any attention a couple of years ago.

As well as Ebay there are other places to look for good used gear. Gumtree is one such place. Here's a selection of ads from up and down the country that caught my eye. My criteria was to keep the total spend under £120, and to avoid anything where the failure of one component would render the entire system useless, and the gear had to be capable of outclassing anything you might buy retail in the £200-£300 price bracket. In some cases you'd have to spend £600-£800 new to match the performance. END OF QUOTED MATERIAL

Lucid (and anyone else that would like to chip in), in spite of your helpful advice, my wife and I decided not to buy used equipment, since one can never know how long it has been used etc. However, in considering what to replace the Daewoo with, I have met up with a further problem, and it is this. What we need is a fairly small (to fit on top of what is a wooden "tower" — a tall wooden CD storage cabinet, the top of which is about 14 inches square) combination (matching separates, if necessary) of radio inc. FM and CD player. We already have speakers, mounted on the wall. It would also be nice to have a USB port on the latter, to connect a flash drive with the player, but that would not be essential. However, when I look an the Web, at the Denon DF109DABC DAB/FM/CD/Receiver Mini Separates System and the similar Pioneer, it would seem that they do not play lossless music (or AIFF files either). Now, both my pre-recorded CDs and the burnt-on-my-Mac computer CDs all contain lossless AIFF files/tracks. Therefore, I am at a loss about how to buy, with confidence that all of my CDs will play, any separates system such as I describe. The Daewoo, with all its faults, would play just any CD, whether pre-recorded or not. I was looking at a maximum of £300.00. Can you, or anyone else, offer some useful information with regard to this kind of purchase? Thanks in advance!
A.W.

 

[Lucid]

There might not be a quick way to find something suitable. You may end up just having to read the specs or even download the manuals. There's a Panasonic (SC-PMX70) that will handle AIFF. Review and available from Amazon and elsewhere I am sure. I looks like the Panasonic is available only with speakers included rather than just a main unit.

 

[Lucky Luke]

There might not be a quick way to find something suitable. You may end up just having to read the specs or even download the manuals. There's a Panasonic (SC-PMX70) that will handle AIFF. Review and available from Amazon and elsewhere I am sure. I looks like the Panasonic is available only with speakers included rather than just a main unit.

Hi, Lucid, I know that it's a long time ago that I raised the problem that I had with my old Deawoo music centre (CD playing being the problem). However, I feel a need to re-open the discussion in the light of recent events. I did not find a suitable replacement for the Daewoo, but soldiered on with it. I found something out a few months ago, and this was that it was not necessary, after all, to warm the CD (I had gone through this rigmarole for a long time, then found out that it was a waste of time). I can't remember what prompted me to do this, but, instead of warming the CD, I just put it on the turntable (it can contain five discs, if necessary) and closed the sliding drawer. This then rotates the turntable until the inserted disc is underneath the lens/playing apparatus. Then, the machine tries to read the CD. As usual, it failed to read. Instead, an error message appeared on the display, which said, CD error. Now, a genie must have inspired me that morning, because, instead of taking the CD out and polishing it, warming it, etc., I just closed the drawer again. Once again, the turntable rotated and set the CD underneath the lens etc. Again, the error message appeared. This process was repeated (deliberately, by me) many times, until (on about the twelfth attempt), I saw the magic words: READING. The CD actually started playing! This CD was a lens-cleaning CD, so I let it clean the lens. Then, I inserted another CD and it played first time. Then another — it played. And another, and it played first time, every time.

With this, I thought that the problem had been cured. However, a month later, I put a lens-cleaning CD into the turntable, and went through the rigmarole (having vowed to make sure that the lens was cleaned regularly). Once again, the alert showed:— CD error. So, I did what had been done before, and kept on attempting to play it, by opening the drawer, closing it again etc, until (after a dozen or so tries) it played.

I find that this always happens. It just is not possible to simply put in a CD and play it right away — many attempts are needed. I have a routine whereby, every month, I put in the lens-cleaning CD and clean the lens. It always works once it has been attempted several times (which, really, is not acceptable). Today, it took twenty-one attempts before it would play the CD-cleaning disc. By the way, the eventual success does not seem to have anything to do with the machine "warming up", eventually. (I have tried switching it on first, and leaving it on for half an hour, but this makes no difference — it still takes many attempts before it will read a CD.)

Not being a technically-savvy person, I don't know why it takes so many attempts before a disc can be made to read/play. However, once the initial success has been achieved, it DOES read/play. Can anyone explain what is happening, and how this machine can be made to play straight-off (assuming that the lens is cleaned regularly)? As it is, when we want to listen to a CD, it simply is not worth the trouble. Also, because I am in my eighties, to be crouching so long is a great strain on my back.

Thanks to anyone that can shed any light on this problem.
A.W.

 

[Lucid]

Hello,
It sounds like all the time you're going through this routine, the machine itself is warming up. Once warm, then everything is hunky-dory. Once it has been off for a while - and presumably cooled down a little - then it's back to square one.

There's a certain type of component that follows the same 'works when warm, fails when cold' pattern. That's a capacitor.

Capacitors are used all over bits of consumer electronics, and that includes the power regulation circuits for laser diodes. The laser is very sensitive to how much power it receives. Too much or too little will cause it to stop working. The capacitors are part of the circuit that governs how much power the diode receives, so if one or more of the capacitors go out of whack then the diode won't run right.

Capacitors come in lots of different sizes (see image below)

...and even some that are smaller than the tip of a ball point pen

... so finding the right one can be tricky even with the short cuts used by bench engineers.


If you want to have the Daewoo fixed, then this would be a start, but IMO it wouldn't be cost-effective compared to replacing the unit with a used Denon DAB 40 or similar.

Warming the disc probably adds enough heat energy to kickstart the failing capacitor(s).


If this or any other reply was helpful to you, then please do the decent thing and click the T-H-A-N-K-S button. It appears when you hover the mouse pointer near the Quote Multi-quote buttons. This is the proper way to show your thanks for the time and help someone gave you.

 

[Lucky Luke]

Hello,
It sounds like all the time you're going through this routine, the machine itself is warming up. Once warm, then everything is hunky-dory. Once it has been off for a while - and presumably cooled down a little - then it's back to square one.

There's a certain type of component that follows the same 'works when warm, fails when cold' pattern. That's a capacitor.

Capacitors are used all over bits of consumer electronics, and that includes the power regulation circuits for laser diodes. The laser is very sensitive to how much power it receives. Too much or too little will cause it to stop working. The capacitors are part of the circuit that governs how much power the diode receives, so if one or more of the capacitors go out of whack then the diode won't run right.

Capacitors come in lots of different sizes (see image below)

View attachment 168934

...and even some that are smaller than the tip of a ball point pen

View attachment 168933

... so finding the right one can be tricky even with the short cuts used by bench engineers.


If you want to have the Daewoo fixed, then this would be a start, but IMO it wouldn't be cost-effective compared to replacing the unit with a used Denon DAB 40 or similar.

Warming the disc probably adds enough heat energy to kickstart the failing capacitor(s).


If this or any other reply was helpful to you, then please do the decent thing and click the T-H-A-N-K-S button. It appears when you hover the mouse pointer near the Quote Multi-quote buttons. This is the proper way to show your thanks for the time and help someone gave you.

Thanks for your reply, especially the specific information. However, I thought that I had made it clear that I had left the machine switched on for half an hour, in order to see if warming up was the relevant factor. (It made no difference.)

I shall certainly study what you have said, and see if anything you suggest will help.
A.W.

 

[Lucid]

Until an engineer gets it on the bench, and does some trouble-shooting, puts an oscilloscope on various removed components, then all anyone can provide is best guess based on past experience and the bits of information provided.

I take it you've done your own web searches? I note you haven't mentioned the model number so far, but I'm guessing that it may not make much difference as Daewoo wasn't ever regarded as a higher-end audio company in the UK, so its audio systems were aimed-at and sold-as entry-level/budget products. On that basis, it's very likely that any which failed were dumped by their owners rather than being repaired. The lack of Daewoo audio systems offered for sale (current / completed) on the UK versions of Ebay, Gumtree, Preloved and AV Forums kind of confirms that.

You mentioned warming the CD (disc, I presume?), and TBH, I was being kind when I suggested it might have some effect. Whether you warm the system itself may be irrelevant too. It may be that attempts to start the CD playing result in current flow in those circuits that leaving the system on can't affect. Again, it's all best guess though, and just delaying the inevitable day when, no matter what you do, it just refuses point-blank to play any disc.

It's time to face facts. Unless you have direct experience yourself doing electronics repairs then your options are limited to either taking it to a repairer or replacing it because it's faulty. @DaveHerns told you straight almost four years ago. I've made very strong hints in that direction too. Now I'm telling you straight as well. It's buggered. Tinkering around from the outside won't fix it.

You've had the system for almost 15 years, and by the sound of it been buggering about with a faulty CD mechanism for 12 out of those 15 years. For the love of God, don't you think it's time to end your misery? Enough is enough.

 

[Lucky Luke]

Until an engineer gets it on the bench, and does some trouble-shooting, puts an oscilloscope on various removed components, then all anyone can provide is best guess based on past experience and the bits of information provided.

It's time to face facts. Unless you have direct experience yourself doing electronics repairs then your options are limited to either taking it to a repairer or replacing it because it's faulty. @DaveHerns told you straight almost four years ago. I've made very strong hints in that direction too. Now I'm telling you straight as well. It's buggered. Tinkering around from the outside won't fix it.

You've had the system for almost 15 years, and by the sound of it been buggering about with a faulty CD mechanism for 12 out of those 15 years. For the love of God, don't you think it's time to end your misery? Enough is enough.

Lucid, if I had been able to buy a new one (I would not buy any used model) that would play home-burned CDs, I would have done so when I first raised the problem on this forum about 4 years ago). I even ordered a machine, and, just in time, found out that it would not play home-burned CDs, so luckily, there was time to cancel the order. I felt forced to mess about with the machine that I have, because it seemed that it could not be replaced. I should not like to lose our means of playing music.
Just as a matter of interest, this morning, (unusually), I did another test (normally, it might be three or four weeks after), and put a CD disc in (the lens-cleaning disc). To my astonishment, it read the disc right away, first time! (I don't think this would have been the case if it had been left unused for a week or more.) It never has worked before now, after a week of idleness. However, to make things even worse now, even though it is playing, it is "stuttering", as if there are minute bits of track missing.

In the absence of new machines on the market that will play home-burned CDs (this is the bulk of our music), I may be forced to ask a technician to look at it. Depending on the price he would charge, it would have to be handed to him for repair. I suppose that, if it could indeed be fixed, I would be willing to pay as much as I paid for the machine in the first place.

Anyway, thanks for your comments. I suppose that this thread is now closed, since I now know what I must do if I want the machine to be put right.
With kind regards, A.W.

 

[gman76]

Hi AW,

I have a few points to raise here:

I would suggest if you have intent designs on resurrecting your machine - please stop using the lens cleaning disc, in my experience these do more harm than good. You already mention that you have cleaned it manually. This should be sufficient.

I think I'm right in saying that pretty much all CD players will play home burnt CDs (CD-Rs), some may be picky about CD-RWs though.

There is definitely a fault with your player at component level that will require expert attention.

 

[Lucky Luke]

Hi AW,

I have a few points to raise here:

I would suggest if you have intent designs on resurrecting your machine - please stop using the lens cleaning disc, in my experience these do more harm than good. You already mention that you have cleaned it manually. This should be sufficient.

I think I'm right in saying that pretty much all CD players will play home burnt CDs (CD-Rs), some may be picky about CD-RWs though.

There is definitely a fault with your player at component level that will require expert attention.

Thanks for your comments, gman76. What you say about lens-cleaning discs comes as a great surprise to me! I suppose CD players can be bought. However, this is a music centre that has radio, tape-playing facility and CD playing. I know of no music centres that can play home-burnt CDs. If there are any, I should be very glad to hear of some (in the uk market).
Regards,
A.W.

Four years ago, when looking for a replacement for our defective music centre, I think I must have entered something like HiFi in my search term. This is because I imagined that mere "CD players" were tiny things — not much bigger than the CD itself — and that they would not have speakers. Today, I found out that this was mistaken. Just out of curiosity, I typed in "CD Players", and found a host of them, at reasonable prices,, some with built-in speakers and some with separate speakers. So, I seem to have found what I needed, at last.