I must take back my statement about the Onkyo DX-120 being able to play burned discs (CDR). Although it initializes them and “plays” them they don’t sound good. There is both background hiss and some audible distortion and fuzziness. The loudness of the hiss varies in time with the disc rotation speed. The sonic effect is similar to the sound of a very weak FM radio broadcast which is nearly at the point of fading out.
I suspect the RF level recovered from a burned disc is at the very minimum level which can be processed by the decoder IC.
The DX-120 plays factory-pressed discs perfectly except when they have major scratches on the disc surface. Extremely bad scratches may cause the DX-120 to stick or skip.
When I play the same burned disc on a more recent machine such as my Sony DVP-NS999ES there are no audible defects or background noises. Disc players newer than the year 2000 also handle discs with scratches and surface damage better.
I have a question for diyAudio members:
Is there a list of pre-2000 era CD players which ranks them according to whether (or not) they will play burned discs?
-EB
I suspect the RF level recovered from a burned disc is at the very minimum level which can be processed by the decoder IC.
The DX-120 plays factory-pressed discs perfectly except when they have major scratches on the disc surface. Extremely bad scratches may cause the DX-120 to stick or skip.
When I play the same burned disc on a more recent machine such as my Sony DVP-NS999ES there are no audible defects or background noises. Disc players newer than the year 2000 also handle discs with scratches and surface damage better.
I have a question for diyAudio members:
Is there a list of pre-2000 era CD players which ranks them according to whether (or not) they will play burned discs?
-EB
Hi EB,
I already told you that at 10% above the rated Iop, the laser head is considered to be bad. 25% is way too high, you have a great deal to learn. Reading what you have been told would be an excellent start.
Burned CDs vary greatly in quality. Any such a list you are considering would be an exercise in futility. They make test CDs so you have a standard to work against. That is what you need to use.
The head is toast, just buy another and get on with setting it up. DO NOT ADJUST THE APC pot on the head. While you are at it, you may find the disk (spindle) motor has worn bearings. I normally replace them as a pair if the head is bad. If it uses a pressure clamp system, inspect / repair the area where the rotating table presses against the flapper. If the disc clamp is magnetic, there shouldn't be a pressure type clamp.
Those meters have hot spots on the sensor. Find the point where it reads the highest and use that. I have a pair of those meters and bought a few for my shop. I am very familiar with them and their characteristics. If you don't have one of those meters, do not mess with the APC power setting.
Hey, I am detecting a theme here. Do not adjust the APC setting!
-Chris
I already told you that at 10% above the rated Iop, the laser head is considered to be bad. 25% is way too high, you have a great deal to learn. Reading what you have been told would be an excellent start.
Burned CDs vary greatly in quality. Any such a list you are considering would be an exercise in futility. They make test CDs so you have a standard to work against. That is what you need to use.
The head is toast, just buy another and get on with setting it up. DO NOT ADJUST THE APC pot on the head. While you are at it, you may find the disk (spindle) motor has worn bearings. I normally replace them as a pair if the head is bad. If it uses a pressure clamp system, inspect / repair the area where the rotating table presses against the flapper. If the disc clamp is magnetic, there shouldn't be a pressure type clamp.
Those meters have hot spots on the sensor. Find the point where it reads the highest and use that. I have a pair of those meters and bought a few for my shop. I am very familiar with them and their characteristics. If you don't have one of those meters, do not mess with the APC power setting.
Hey, I am detecting a theme here. Do not adjust the APC setting!
-Chris
I have a genuine Sony YEDS-18 with factory handwritten QC initials in Japanese on it. Problem though: It is very old and is thoroughly scratched in some places. I also have 3 genuine Philips test CDs: test CD 4, test CD 4A, and a “burn-in” disc. The burn-in disc has something like 20 tracks of what sounds like a 1kHz test tone. These test CDs certainly do have cleaner eye patterns than most music CDs.
However I did find a couple of “factory-pressed” music CDs which deliver “textbook perfect” eye patterns that look even cleaner than the Sony/Philips test discs. By “cleaner” I mean the crosshatch pattern in the middle of the eye looks like it was drawn with a ruler. No variation, fuzziness, or amplitude modulation at all.
Regarding that poor old TAOHS-DG2 optical pickup, I haven’t ever seen this pickup for sale anywhere. There are people selling other varieties of TAOHS pickups but those have an entirely different aluminum casting which wouldn’t work at all in this machine.
If memory serves me this Onkyo DX-120 once had a sticker on it stating it was “diagnosed with a bad pickup and retired in the early 2000’s because an exact replacement pickup was already unavailable” way back then. I put it on my workbench mostly out of curiosity to see if I could get any signs of life out of it at all.
I totally agree with you that APC trimpots should never be adjusted casually.
-EB
A couple of days ago I ordered some KSS-240A CD pickups from an Asian eBay dealer who has 99.7% positive feedback. I have an entire shelf of old CD players which contain the KSS-240A.
I wonder how well these contemporary generic versions work?
I’ll find out soon enough.
I’ll also keep my eyes open for a TAOHS-style pickup with the proper physical mounting surfaces. The Onkyo DX-120 requires the style with a vertical attachment surface on the left side where the nylon slider bolts on with two small screws.
-EB
As in this?
Poorly molded black plastic sliders = junk
Pressed-in sintered bronze slider bushings = probably OK
Pressed-in sintered bronze slider bushings = probably OK
I’ve been working a lot lately with 2002-2006 Sony DVD/CD/SACD players which contain pickups like the KHM-240AAA, KHM-270AAA, KHM-310BAA. Their transports & slider assemblies are (mostly) plastic. But these are all original Sony parts. No generic knock-offs. And many are still working quite well mechanically.
I got started on this when I acquired a Sony DVP-NS999ES which required replacement of its optical pickup. It takes the KHM-270AAA.
I discovered that a nearly inexhaustible supply of KHM-270AAA pickups can be harvested from popular low-end models like the DVP-NS715P which turn up “for free on the curb” up to about $20 for an entire DVD player in working condition.
But to restore older CD players I’ll need some “modern generic replacement” optical pickups because all the original Sony-made parts are long gone. I thought I would begin with machines containing the KSS-240A because there are so many vendors for this pickup.
For laughs I also saw that people on eBay are offering the KSS-151A for $300-500 USD each. (That isn’t in my price range.)
-EB