What normally happens to DC player lasers as they age? I have a Kyocera with a marked laser current of 68 mA and the manual says it should be within 10% of that value. It's a bit higher than 10% and the player has yet to be determined issues (breakup or won't read), especially with CDRs. Because the signals look good, I'm suspecting some other problem, but the laser does creep up to 80 mA after a while. Is it possible/common for the signals to look good, i.e., clean and of good amplitude, yet still have a laser problem?
Hello Conrad, higher laser current can cause higher laser light intensity, and consequent saturation/clipping of signal recovery photo diodes and/or HF signal amplifying stages.
I would take a close look at the level/quality of the HF/EFM signal with a CRO.
Notes on the Troubleshooting and Repair of Compact Disc Players and CDROM Drives
Dan.
I would take a close look at the level/quality of the HF/EFM signal with a CRO.
Notes on the Troubleshooting and Repair of Compact Disc Players and CDROM Drives
Dan.
In old Kyocera upper-end models, with the big, beautiful NEC laser, as in the Nakamichi OMS-5/7, you CAN'T judge the laser health by either current draw OR optical power output alone. You have to measure BOTH. If these lasers draw too much current(don't recall the % vs spec) to get to adequate optical power output(0.24mW is spec, but 0.2mW will do ok), it will NOT be possible to make the unit read/track cd's consistently and laser replacement is a must. They are ALSO very tricky to do the other adjustments upon, as you can't rely entirely on the manual AND you MUST adjust with a wide variety of cd's, not just one or two, and find the best compromise, or the unit again won't be consistent. If you search on Nakamichi OMS-5 or OMS-7 on this forum, I think you'll find some more detailed notes from me on handling these players.
If you have a lower or later model Kyocera, with a Sony KSS123 or other Sony laser, you only need, but do NEED, a laser optical power meter, as adequate output is all that matters, not current draw, much, although knowing the current helps judge remaining life expectancy. Other adjustments are not quite as finicky as the NEC laser models, but almost.
If you have a lower or later model Kyocera, with a Sony KSS123 or other Sony laser, you only need, but do NEED, a laser optical power meter, as adequate output is all that matters, not current draw, much, although knowing the current helps judge remaining life expectancy. Other adjustments are not quite as finicky as the NEC laser models, but almost.
Interesting! I have an older Kyocera player with the big laser and it needed significant mechanical alignment to get it working. Not sure what happened to it, but I think somebody else just gave up on it when electrical adjustment didn't work. Seems fine now, though it needs a new belt. My 710cx has always been a bit finicky but in general works well. Most recently the focus servo drifted off a bit, but readjustment seems to have taken care of it. I've read about sagging lens suspensions. Sonically it's as good as I've found.
The player on the bench now is a 510cx that I bought as a parts unit. Naturally I want to get it working if possible, and it just seems too close to give up and part out.
I don't have a power meter handy, but could get my hands on one. I do have an infrared viewer and that at least confirms a nice bright spot.
re lasers- if an assembly isn't available, has anybody ever successfully changed out just the laser in the module?
The player on the bench now is a 510cx that I bought as a parts unit. Naturally I want to get it working if possible, and it just seems too close to give up and part out.
I don't have a power meter handy, but could get my hands on one. I do have an infrared viewer and that at least confirms a nice bright spot.
re lasers- if an assembly isn't available, has anybody ever successfully changed out just the laser in the module?
Ah, yes, forgot about the optical azimuth & zenith alignments on the big NEC based models. Almost never need re-doing as long as nobody has messed with them.
I think the 510cx is a Sony KSS123A laser, yes, or close to that? These generally respond well & for years to laser output re-adjustment, as long as done with a proper laser power meter(e.g., Leader LPM8000), to no more than the 0.24mW spec.
I think the 510cx is a Sony KSS123A laser, yes, or close to that? These generally respond well & for years to laser output re-adjustment, as long as done with a proper laser power meter(e.g., Leader LPM8000), to no more than the 0.24mW spec.
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