CD Players

[Enzo]

We work on amps all the time, but some of my customers use other things. DJs use CD players, and so do exercise programs. I have more aerobics instructors coming to me than you might think. They use these things to death. You can buy a perfectly good new CD payer for under $30 with a warranty even. But they buy nicer ones that have a pitch/speed control. They can adjust the speed of the music to fit the planned activity.

I do a little consumer electronics repair, just as a courtesy to the community. No TVs or computers, thank you, just audio. But mainly I do semi-pro stuff. GJ dual players with remote control panel or TASCAM stand alone units.

I hate to turn away these customers, I may not like the CD player, but it establishes the relationship, so when they need service on their amp/mixer/speakers, they come to me, not whoever they would have turned to in the first place.

Only so many things to fix in a CD player.

The optical laser pickup. In my experience, pretty much they need cleaning, they need replacement, or they work. Cleaning is simple. SOme 99% isopropyl and a Q-tip, gently wipe the lens. It is a tender little thinig, but so is your eyeball. If you can put in a contact lens, you can wipe a laser lens. SOmetimes you have to move the tray out of the way to get access.

If cleaning doesn;t restore operation, then a new laser is probably the cure. And now we are talking $$$. Lasers don;t come much cheaper than $30, and can get up to $100 or more. That is my cost. So retail to customer is $60-150, throw in an hour labor and they probably won;t go for the repair on a basic unit.

The laser assembly slides on greased rails with a geared motor driving it, mostly. Portables use a swing arm a lot, but we don;t fix those. If those rails get dirty or sticky, the player can skip. And if those gears get a bit of grit or some hair in the teeth, that can cause sticking and skipping. I know sometimes after I skip, I find hair in my teeth. SO if skipping, and we cleaned the lens, clean the rails and gears, then fresh thin coat of white lube.

I just HATE those 6 CD stack deals. They are a jam waiting to happen.

The tray has to move in and out, and raise the laser assembly to clamp in the disc. SOme drive direct, but most involve a little belt. If the belt loses tension or grip, then the motor can have a hard time moving the tray. A lot of times it can close the tray but the extra oomph to pull the laser up tight is more than it can handle. Belt slips Replace the little belt.

There will be litle tiny blade switches or tiny microswitches that sense tray position. They tell the controller when the tray is all the way out and all the way in or "home." If the tray switches don;t work, the tray can cycle in and out on its own, or refuse to stay open. If it can't sense home, it may not read the disc.

Once in a while, you have to resolder the dual RCA jacks on the rear.

And the controls. Whatever the buttons on the panel look like, chances are that under them are the very common 6mm square "tactile" button switches. They usually wear out the stop, play, tray in/out ones, and sometimes the others. You find buttons that just don;t work, or that you have to puch hard or that you have to kinds puash sideways. If a couple are bad, I just replace all 10 of them, they are cheap. Look at them closely, they come in two leg and four leg types, and watch the heighth. a 4.3mm and a 5mm tall switch look about the same, but that little difference can mean buttons that don;t quite reach or button that stay pushed when the panel is assembled.

I don't remember the last time I saw one with an actual electronics problem. If one audio channel is out, look for a bad op amp driving the output jack.


Really, ther is not a lot to servicing these, and if it makes a new customer, worth the effort.

[Mitchy]

Thanks Enzo for a few useful tips there.
Dont really look at CD's etc myself but pointers to possible faults are always useful.
Cheers Mitchy.

[tedmich]

and you shouldn't leave a CD in the player, as the laser beam will flatten when its turned off; then it skips.

or was that cassette tapes?

[Jazz P Bass]

American DJ has the complete CD tray for $20.00.(for there units)
The laser assembly is a Sony.
If you try to buy the Sony part it is close $100.00.
The real pain is that little CD ribbon cable.
If you are a little ungentle reinserting it, the leads can peal back.

[Ronsonic]

Just a couple of comments from a CD repair spectator, I've done 'em but am not exactly (at all) expert, but I work with a guy who is ace with these.

Often it is better, faster, easier to replace an entire mech with spindle motor, laser, tray and all. This is often more economic as well. Lift off and nuke from orbit. In some cases this is the only part available.

A lot of the internals are standardized and can often be found very economically, as Jazz was suggesting.

Don't forget to remove the little solder jumper on the laser assy!

[jrfrond]

Nowadays, most of the CD Players we repair are double DJ units, but there are a few pro units we service as well. But most of the CD work we do now is on CD burners.

CD players have come a LONG way since I went for training (4 days, mind you) at Sony in NJ in 1983 to learn the CDP-101, the first commercial player. You had to calibrate EVERYTHING in those. Today, everything is automatically calibrated. There no tracking and focus servos to calibrate anymore. Most of the current laser pickup assemblies are made by Sony and are notorious for their failing lens support springs. Once they sag and the focus servo cannot compensate, it's time to replace it and yes, they often come as an assembly with the sled and spindle motors mounted. Dirty lens? I can count on one hand since 1983 how many times cleaning a lens has solved a problem.

[km6xz]

CD players are looked down on by many shops as mere consumer products, from which they came of course but in the overall scheme of things, they ARE more main stream pro audio than guitar amps. More pro DJs are working and earning a living in music than working musicians who usually play for the fun of it. In larger cities, there are at least 20 times the venues that will pay a DJ than venues that would hire a band. For a whole generation the computer and DJ IS music 2011, all else is an impersonation to the most recent generation of consumer.
With that in mind, those who limit their work to guitar amps, and even more so for those shops catering only to tube amp work are increasingly fighting for a shrinking market share of a shrinking market.
Currently I am repairing for the fun of it but if I get a real office eventually, paying the lease will mean doing DJ gear more than guitar amps, pa amps or mixing consoles. Just like when digital recorders became the main focus of hobby music or semi-professional production very few shops invested in the gear and techs to master digital decks so those who did got, for 10 years, a large share of an expanding market.
CD players are very complex and self calibrating now, the complexity is in circuit sophistication that just happens to be shrink down to a single chip. For a low cost consumer based item they are very reliable and absorb a lot of abuse. For a generation pro or semipro audio has piggybacked on consumer standards, media and user interfaces which means pro audio always lags behind in price and performance, making do with what the large consumer brands adopt as standards. The music production market is just too small for any original unique systems that are independent of the consumer base technology. That is limiting but also makes gear more reliable and very very cheap. If guitar amps were made to the same technical standard of consumer or computer electronics they would be 100 times more reliable, 100 times higher performance and cost $59.
So, for pro repair shops, DJ and computer based interfaces are the current main street where a profit can be made since they are the dominate stream of music electronics use and production nowadays. Personally I like working on larger items that have individual components(prefer SMD for ease of repair and refurb) but know that if I become less selective...now,only repairing things for people I like and gear I like...there is a larger essentially untapped market for repair. That is the reality of electronic repair today. That has been the reality of any technology based repair industry, the newer gear is not so much of repair hobby interest. People generally get into music repair because music is the hobby, or because the standards of performance as entry qualifications are so low. For me, music was not a hobby, electronics was as a kid and music was my profession in design, recording and occasionally producing records and recording gear. So for me it really would not make much difference of the gear I am repairing is a piece of lab equipment, medical electronics, robotics, or even a guitar amp. In that respect I am probably the odd duck in a field dominated by hobby aspects of the craft. So for me, to have a music related shop means working on what is out there that people value enough to seek repairs, regardless of what it is. My only regret with CD players is that there is very seldom an electronics problems with them, I like problems, they are fun and that is my hobby. More complex problems are more fun than easy or routine problems. I get few "virgin" problems, ones that have not been molested in an ill-conceived repair attempt. So repairing something that has been mucked up by a shop or amateur who finally gave up is usually a more complex and thought provoking process than just fixing a problem that occurred and was left unmolested before bring it to me.
I just returned last night from a month long road trip around Ukraine....thinking about opening an office in Odessa and Sevastopol on the Black Sea...and dropped into a few music stores to see what was selling and if there were repair shops. Unfortunately most of the manufacturers gave blanket distribution rights to 2 large distributors in Moscow Russia for an area including Ukraine which is not part of Russia. That means that shops can't get repair parts and customers are stuck with no shops for maintenance. The distributors think that any defect should be solved by the customer buying a new unit and refuse to allow any parts to be sold or even imported into the countries they control. Western companies are really dumb in how they handle their foreign distribution. That stupidity will limit their sales worldwide, which is a much larger potential market than the US and UK which is all they care about. In that, ALL major brands in music electronics will be Chinese in 20 years. Companies like Fender, Marshall and the major Japanese brands will be crushed in the larger world market because of poor distribution strategies and policies. The US share of the world market is shrinking and all those companies will be left with unproductive world distribution that will cripple them no matter how much of the US and UK markets they dominate for now. In that respect I think there is a future for a repair industry to evolve isolated from the majors, just like there has been in auto parts and appliance parts after-market. The volume will be there if anyone wants to go after it.

[Steve Conner]

Well, I guess this piggybacking on consumer audio explains why S/PDIF is used in pro-audio, even though it's possibly the world's worst interface. And for ADAT lightpipe they reused the same cheesy plastic Toslink cables.

The old British hi-fi brands like Quad and Celestion are Chinese owned now.

I'm currently working (for fun I guess) on an Electrocompaniet Class-A hi-fi amp that was screwed by a previous repair attempt from a "professional" tech. It took out one of the guy's woofers from DC offset, then after being "repaired" it took out another one. The board is burnt, the TO220 output transistors are exploded, and the DC offset protection never triggered, because it doesn't have any. This was supposed to be the world's best hi-fi amp in the 70s, too!

[Jazz P Bass]

Welcome back Steve!
Yeah, I am not a fan of 1970's amplifiers.
Obsolete this. Hard to find (ie:expensive) that.
It is strange that there was not any DC protection on that amp.
They made some nifty protect IC's back then.
Like the TA7317P.

[km6xz]

Back in that day, consumer gear was crude and did not use any complex standards that prevented small companies from rolling their own and deviating a lot from industry standards. Around that time I had a contract with a speaker company to design a digital tuner to accompany their power amp and preamp, and very successful line of speakers. The designer of the power amp was pretty sharp but the company's sophistication of production capability or his middling concern for bullet proof circuits caused a lot of headaches with blown up amps.
They liked my capacitor phone cartridge and wanted to produce that but I knew it required more precision than any of us was capable of. To think how forgiving customers were about their expensive power amps blowing up on a regular schedule I doubt customers would be so agreeable and patient. I did build a prototype FM tuner that worked but recommended that they not build it because it would be more complex than a power amp or basic preamp that was already running them ragged. I never figured out why they were interested in building gear they were not good at, electronics, when they had such success in the field they started in, speakers. They were pretty esoteric when starting using electrostatics and KEF woofers in Helmholtz baffles. They ended up with the license for the Heil Air Motion Transformer in very crude not-ready for production state. I worked on my project at home since I had other clients as well as recording but I shared a office/lab with Nelson Pass who ended up redesigning the Heil HF driver and got it to work really well. He was their speaker guy just out of college.
Everything was so crude than, except maybe McIntosh. Few people liked the sound of Macs but they were very nicely built compared to everything else at the time. The lack of sophistication of equipment at the time was so low that kits such as the HeathKit and the Dynaco kit series for home construction were competitive with features and performance of the best commercial brands.
By the way, Sherwood beat us to market with the first digital tuner by a month.

[Steve Conner]

Thanks JPB, it's good to be back I've been busy supporting the launch of our new product.

Digital tuner, I had to think about that one for a bit. I guess you mean an analog FM tuner with a PLL frequency synthesizer and a neat digital frequency display, which would have been really cool back in the 70s I used to use a Cambridge Audio tuner that was properly digital in that it did DAB digital radio, and also demodulated FM digitally with the same DSP hardware. I gave up on it because my favourite radio stations now stream to the Internet in higher quality than they broadcast DAB. So digital tuner now means a laptop. And to me the FM side never sounded that great.

Not only does the EC have no DC protection, it's DC coupled! So if you wanted, you could fry your speakers by applying a 1.5v battery to the input. I think it's from the audiophile school of design that says that protection circuits degrade the sound. Of course this conventional wisdom is based on sound economics, as leaving out the protection lets the amp drive difficult loads with fewer pairs of output transistors. Which gets us back to crudeness and amps that regularly blow up.

I couldn't get exact replacements for the original BD203/204 output transistors. I fabricated a heat spreader block to replace them with the universal MJ15024/5

[Chuck H]

Nice to see you pop in Steve. As always. I'm sure I speak for most when I say that I've been hoping the best for your current venture and looking for your return here as well.

[km6xz]

Yeah, it all seems so long ago, technology wise, but that when it was hard to build a PLL synth for local oscillator for a piece that was affordable, no one had yet. It worked really well and FM WAS radio at the time. AM stations where going out of business left and right. That lasted until the late 80s when the music industry...and therefore the touring, recording and radio industries collapsed. By the mid 90s you could buy a FM station and license for pennies.
The only time I listened to the radio was when driving, even then I preferred listening to the engine and trans-axle working. After spending so much time in the studio the last thing I was to do was listen to recorded music. I preferred live performances of mediocre groups to listening to great records. I built lots of high performance hi-fi systems but seldom listened to them. They were mostly for guests who expected to hear something or for parties.
We had a problem with transistors at that time, any abuse and they were gone. The 2N3773 was the first power transistors with an extended secondary breakdown region, that could life in amps with varying load Z and high peak currents. Almost all the current power transistors are more suited to amps than any we had back then.
What a change, now class D amps are so efficient that they hardly need a heat sink. Yesterday I bought a little module with one surface mount IC. 1.5 " wide and 2 " deep for 620 Rubles, about $18. It is two channels of amplifier, no heatsink and is 15 watts per channel, running on 12.7 volts from my bench supply. I stuffed into a speaker cabinet as the power amp for a set of small monitors on the bench. It is so light and small that I stuck it into place with double sided tape. For my larger bench monitors I plan on getting another module that is 300/cha but uses a separate 48V/ 8amps switching supply which cost me $45. It even has SPDIf inputs as well as balanced and unbalanced inputs. Cost, $80.
A pa/club speaker company here asked me to design a power amp for active subs. I told them that for their budget they should buy ready made Class D modules. I found them one in China that is 1000RMS with really good specs, with on-board switching supply. The backing plate acts as the heatsink with short fine that are exposed to the outside of the cabinet. It is a beautifully engineered model and does cost more than my little hobby modules but not too much more for the quality, $200.

[Gtr_tech]

I'll pick up vintage cd players occasionally for a few bucks at second hand shops. Currently in my audio rack is a Braun/ADS CD3 that I really like. Its built like a tank and sounds very good.

Other than replacing belts, I find that the calibration trimpots can become intermittant and need cleaning. I'll just mark the position with a sharpie, work some cleaner into them and run them end to end a few times. Takes care of the issue.

The last one I bought was a Technics SLP-1 from 1985. All I needed to do with this one was replace belts and clean/lube the sled mech. Took right off with no issues. The only snag I ran into was the belt used to move the sled....it was real small and I didn't have one to match it. So I used a rubber o-ring just to see if it would do the job reliably. And it did....