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Troubleshooting CD Players
- Thread starter dr*audio
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I've never had a CD player yet that a cleaning disc actually worked on. Have had a few that benefitted from detailed hand cleaning of the lens with a swab (using a minimal amount of 91% isopropyl, not enough to have it puddle on the lens or surrounding areas).
YMMV, bit all a disc with those little brushes will do is remove loose dust from the lens, which could be done as well by canned air. More often than not, there is film/haze on the lens surface that will require more than the cleaning disc is capable of.
YMMV, bit all a disc with those little brushes will do is remove loose dust from the lens, which could be done as well by canned air. More often than not, there is film/haze on the lens surface that will require more than the cleaning disc is capable of.
@j!m, true enough, unless one is comfortable doing it oneself. I am, but certainly recognize many aren't. I've done cleaning and repairs on some Alpine HU's I own as well. I presently have two CD-A7894 head units from 2001 still working beautifully, along with their original 6 disc trunk mount changers. Also have a similar CD-A9833 from about 2004 still in service. These are all in cars form the late 80's to early 90's, and I keep them because they do what I want, and look period correct in their respective applications.
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Here's another thing to look for when repairing CD players.
I was working on a NAD 512 that had been sitting in my closet of junk for 10 years. It needed a Sony CXA1082BQ, which at the time was hard to find and expensive. Now I have a good source for them cheap, so I ordered the part and got it working, BUT, it would intermittently drop out, like it had bit errors. I suspected the sled motor so I monitored the sled motor drive with a scope. It would slowly go up to 0.7V and then the sled would move, but when it dropped out the voltage would go much higher. Aha, I said, bad sled motor. I removed the drive gear and checked to make sure the laser was sliding freely and it was. Removed the sled motor and compared it with a new one, driving it with a bench supply to see what the lowest voltage it would start at. Both motors were the same, about 0.25V. Ok, I figured maybe it has a bad spot and sometimes won't start, so I replaced it. Same problem. So I moved the gear, turning it slowly to see if it hung up, and it did. Removed the gear that drives the rack gear on the laser and it had a bunch of teeth gouged out! I have a few brand new mechanisms I bought when they were available (actually they still are; Liberty Electronics has them) so I pulled a gear off one and installed it in the player. All fixed. I checked the limit switch to make sure it is working, because that could cause the gear to get ground up, but the switch is fine. So, be sure to check the gears!
I was working on a NAD 512 that had been sitting in my closet of junk for 10 years. It needed a Sony CXA1082BQ, which at the time was hard to find and expensive. Now I have a good source for them cheap, so I ordered the part and got it working, BUT, it would intermittently drop out, like it had bit errors. I suspected the sled motor so I monitored the sled motor drive with a scope. It would slowly go up to 0.7V and then the sled would move, but when it dropped out the voltage would go much higher. Aha, I said, bad sled motor. I removed the drive gear and checked to make sure the laser was sliding freely and it was. Removed the sled motor and compared it with a new one, driving it with a bench supply to see what the lowest voltage it would start at. Both motors were the same, about 0.25V. Ok, I figured maybe it has a bad spot and sometimes won't start, so I replaced it. Same problem. So I moved the gear, turning it slowly to see if it hung up, and it did. Removed the gear that drives the rack gear on the laser and it had a bunch of teeth gouged out! I have a few brand new mechanisms I bought when they were available (actually they still are; Liberty Electronics has them) so I pulled a gear off one and installed it in the player. All fixed. I checked the limit switch to make sure it is working, because that could cause the gear to get ground up, but the switch is fine. So, be sure to check the gears!
Good advice by @dr*audio there. Many of the gears used are nylon or similar soft plastics. Many of these age poorly, and can be easily broken if something jams, or gets "out of sync" by a tooth or two, especially where they overshoot the limit of their intended travel. Hardened lubricating grease can also be a contributing factor.
I've also had gears with hairline cracks because they "swelled" with age, and since the shaft they spin on is metal, the gear had to split to accommodate the suddenly smaller inside diameter creating mechanical stress. Sometimes replacement can be found on eBay, if the player is a popular model. Others have to be reinforced somehow for repair.
I've also had gears with hairline cracks because they "swelled" with age, and since the shaft they spin on is metal, the gear had to split to accommodate the suddenly smaller inside diameter creating mechanical stress. Sometimes replacement can be found on eBay, if the player is a popular model. Others have to be reinforced somehow for repair.
Trance88
Vintage Furry
Got a strange problem with my Sony CDP-C260Z. It appears to be "sunsetting" where it works well for a couple hours, but then it starts having trouble reading discs especially the tracks closer to the outer edge of the disc. The audio starts getting super choppy and "fizzly." Eventually it won't even read the TOC. Mostly on CDR's though. It's only from 1997, so I don't think its failing capacitors. If I just use it for like one or two CDR's a day, its fine, but anything more than that, and it starts to fall flat on its face.
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Looks like the laser is failing. It uses a KSS-213. The suffix letter doesn't matter. Liberty Electronics on E-bay has good ones.
Revox H2 CD player will not spin up. I have been trying all the usual spots for schematics or service manual and cannot find anything. Does anyone have any service documentation on this particular model? I know that it uses the Philips CDM4/27 laser but not much else. Any guidance is greatly appreciated.
Most likely the laser is bad. No longer available, but Revox has been really good with parts in the past so maybe they still have the CDM unit.
Dr. isn't it a bit hasty to condemn the laser unit prior to checking the freedom of the slide(s) and possibly the limit switches?
There's always a chance the laser is bad, but having serviced many players now, I've found quite a few other failures; stuck slides, stuck gears (often old grease all hardened up), weak/bad spindle motors, bad capacitors in the servo section, etc. anyone doing routine work on CD players (or planning to) should really get a laser power meter to verify if a laser is good, or failing, as it is far too easy to just blame the laser.
It's a swing arm laser and it's outside of it's life expectancy at this point.
It's a swing arm laser so no slides or gears, and even if it is the disc motor you can't get a replacement for a Philips mechanism, you have to replace the entire CDM assembly. Also based on my experience with Philips based players with CDM type mechs, it's always the CDM unit. Some people say it's the caps but I have never seen that. Replace the CDM unit and it works, so it couldn't be anything else.
@dr*audio, fair enough, as regards the Philips pickups, though neccessity is the mother of invention. I'd expend a fair amount of effort and ingenuity to graft in a new spindle motor on a really nice player. I know that "officially" these pickup assemblies were not intended to be serviceable at component level, but that wouldn't stop me from trying.
Is the saving of one of these players worth such extraordinary efforts invested? Not on paper, nor by any logic, certainly. Then again, the prices currently being paid for many "vintage" players can hardly be justified, yet some still command significant money on the secondary market. But of course sentimentality, and a desire to preserve some of the better older examples of this tech drive some of us to do things that cannot be justified solely on a cost to "payoff" basis.
The Vintage Audio Laser web site has posted some remarkable repairs and restorations. I'm not aware of anyone else operating at that level (and aspire to be able to do such exceptional work myself), but the proprietor of that site has successfully replaced and calibrated the laser diode in TAOHS-L pickups, has created a replacement for a failed PLL circuit module used in several notable Technics models, and has gone to great lengths to preserve many of the most sought after first and second generation players, to great success. Point being that many erstwhile write-offs can be saved, given the funding, advanced technical expertise, and determination to do so. Admittedly, most people won't pull off saves like that, but they are possible.
Is the saving of one of these players worth such extraordinary efforts invested? Not on paper, nor by any logic, certainly. Then again, the prices currently being paid for many "vintage" players can hardly be justified, yet some still command significant money on the secondary market. But of course sentimentality, and a desire to preserve some of the better older examples of this tech drive some of us to do things that cannot be justified solely on a cost to "payoff" basis.
The Vintage Audio Laser web site has posted some remarkable repairs and restorations. I'm not aware of anyone else operating at that level (and aspire to be able to do such exceptional work myself), but the proprietor of that site has successfully replaced and calibrated the laser diode in TAOHS-L pickups, has created a replacement for a failed PLL circuit module used in several notable Technics models, and has gone to great lengths to preserve many of the most sought after first and second generation players, to great success. Point being that many erstwhile write-offs can be saved, given the funding, advanced technical expertise, and determination to do so. Admittedly, most people won't pull off saves like that, but they are possible.
I think I tried to replace one of those spindle motors and the disc table is bonded onto the shaft and I could not get it off.
Regarding a laser power meter, they are difficult to get a good reading with because the lens is going up and down doing focus search, and it only lasts a few seconds. You can usually use a scope to look at the focus error signal. If there is none or it is very low, the laser is bad. Likewise, on a player using a Sony chipset you can look at FOK and see if it gets focus lock. If not, and if there is not Focus Error signal, the laser is probably bad. Rarely the amp IC or the Servo IC is bad. Again, you can determine that with a scope, no need for a laser power meter. We had one at work and I found it unreliable.
Dr. if the limit switches are gunked up bad enough will the unit think a disc isn't loaded, causing the spindle motor to stay idle? Have you ever run into that issue?
If that were the case it wouldn't do focus search.