Quantcast

Page 1 of 6 12345 ... LastLast
Results 1 to 15 of 77

Thread: Sega CD Audio Popping Noise

  1. #1
    Raging in the Streets Blades's Avatar
    Join Date
    Dec 2006
    Posts
    2,920
    Rep Power
    70

    Default Sega CD Audio Popping Noise

    CDs play with quiet popping noises in the audio matching the CD's rotation frequency. The popping isn't in the source material. Is the laser getting tired?

    I have the KSS-240A pickup.
    Last edited by Blades; 03-12-2018 at 03:42 AM.

  2. #2
    Hedgehog-in-Training Hedgehog-in-TrainingWildside Expert
    Join Date
    Jun 2015
    Posts
    163
    Rep Power
    4

    Default

    Sounds like it could be the laser that's dying, you're lucky you have the Sony CD drive, as replacement lasers for that are a dime a dozen. I have one with the JVC drive, and replacement lasers for that are few and far between. By the way, have you replaced the SMD caps on the main board? Those are almost guaranteed to be leaking and in need of replacement.

  3. #3
    Raging in the Streets Blades's Avatar
    Join Date
    Dec 2006
    Posts
    2,920
    Rep Power
    70

    Default

    Do the Chinese 240A lasers ship calibrated or do I need an oscilloscope?

    I havenít changed the capacitors yet.

  4. #4
    Raging in the Streets Blades's Avatar
    Join Date
    Dec 2006
    Posts
    2,920
    Rep Power
    70

    Default

    Quote Originally Posted by Xaranar View Post
    Sounds like it could be the laser that's dying, you're lucky you have the Sony CD drive, as replacement lasers for that are a dime a dozen. I have one with the JVC drive, and replacement lasers for that are few and far between.
    IIRC The Sega CD 2 uses an Optima 6S pickup, which is available on Amazon and Aliexpress.

  5. #5
    Raging in the Streets Blades's Avatar
    Join Date
    Dec 2006
    Posts
    2,920
    Rep Power
    70

    Default

    Well, I cleaned the lens again and the popping is gone now. Strangely enough, right after cleaning it refused to even spin up. I let it sit for a while then it fired right up.

    I'm not using the shielding plates. Could that be the problem? The noise was synchronized to the disc's rotation. I'm using the RCA jacks for the cleanest signal path.

  6. #6
    Hedgehog-in-Training Hedgehog-in-TrainingWildside Expert
    Join Date
    Jun 2015
    Posts
    163
    Rep Power
    4

    Default

    I can't imagine that it would be the shielding plates, I used my model 2 without them and it ran fine. Are you using a model 1 or 2? And, with regards to the JVC laser, mine is a model 1 with a JVC drive, so the laser is an Optima-5S, and those are rare.

  7. #7
    Hedgehog-in-Training Hedgehog-in-TrainingSports Talker majinga's Avatar
    Join Date
    Apr 2017
    Posts
    42
    Rep Power
    0

    Default

    It can't be the shielding plate. Check the capacitors and the belt first. They are the most common cause of failure. Check everything else before the laser.

  8. #8
    Raging in the Streets Blades's Avatar
    Join Date
    Dec 2006
    Posts
    2,920
    Rep Power
    70

    Default

    Well, it sounds fine now. I also lubricated the gears and rail with lithium grease. Maybe the lens just needed a few cleanings. Before, it would sometimes stop early (only once) and grind gears.

    Xaranar, mine is a model 2. Youíre right the model 1 uses a hard to find laser. I seem to recall seeing Chinese Optima 5 replacements at some point though.

  9. #9
    Hedgehog-in-Training Hedgehog-in-TrainingWildside Expert
    Join Date
    Jun 2015
    Posts
    163
    Rep Power
    4

    Default

    I actually managed to find some JVC original optima-5s lasers on eBay, for $34 shipped to the UK. No idea if thatís good or not, but Iíve just bought one as a spare, even though the laser in my unit is currently working perfectly fine, I donít want to be caught short when my laser eventually does die. Better to grab one now while theyíre available!

  10. #10
    Raging in the Streets Blades's Avatar
    Join Date
    Dec 2006
    Posts
    2,920
    Rep Power
    70

    Default

    Nice! Tell us how it works if you end up using it.

    When lubricating, I've heard people suggest removing the old grease. I didn't and simply added a little to the gears and the rail with a q-tip. I did clean the rail with alcohol. I also leaned the limit switch a little closer to the laser.

    I'm still not sure if the laser pots are set at the factory for new lasers. If I ever change the laser, I'll update this thread.

    I should mention that I've never actually seen a laser go bad. It's almost always something else. This would've been the first, but the laser (this one's from 1993) seems to be fine actually. Mechanical failures yes, but never the laser. Even my infamous launch PS2 still works fine with only cleanings.

    Here's an interesting site about laser failures.

  11. #11
    Raging in the Streets Blades's Avatar
    Join Date
    Dec 2006
    Posts
    2,920
    Rep Power
    70

    Default

    It still stops early (on the same pressed CD), as if it's reached the end of the CD. If you seek the last track without playing from the beginning, it plays all the way through.

    Strange.

    EDIT: And again on a different CD. Cold stop during track 1. CD is pristine. Back to troubleshooting...

    It tracks great. It almost never skips in the traditional sense.

    EDIT 2: It seems to be getting lost on long tracks. Perhaps it is a mechanical/sled issue.

    EDIT 3: It doesn't appear to be a cold stop. Rather, it tries to recover and eventually gives up. The sound just cuts out. It's strange because it's completely erratic. It could fail twice, then make it all the way through fine.
    Last edited by Blades; 03-13-2018 at 11:58 PM.

  12. #12
    Hedgehog-in-Training Hedgehog-in-TrainingWildside Expert
    Join Date
    Jun 2015
    Posts
    163
    Rep Power
    4

    Default

    Seriously, try a new laser. They're dirt cheap for your model and work perfectly fine, and yes, they come factory calibrated, I never had to make any adjustments to mine.

    Interesting read about laser failures. I did replace all of the electrolytics in the entire system, not just the problematic SMD ones on the main board - I even, very gingerly, replaced the caps on the laser PCB itself, which wasn't easy to do as the whole thing has non detachable ribbon cables, and was difficult to get into a position where I could reach the solder points without tearing a cable.

  13. #13
    Raging in the Streets Blades's Avatar
    Join Date
    Dec 2006
    Posts
    2,920
    Rep Power
    70

    Default

    I already ordered one, I will update the thread when it gets here.

    From what I can tell, the laser in mine is not an original. The genuine ones seem to have yellow marks on the pots, like in the photo. Mine doesn't.







    Anyways, the pots on mine were all in the middle except for gain which was set a smidge clockwise. I set the gain back to 0 without change. Still didn't recognize CD-Rs either. So I moved all the pots to the positions in the above photo with the yellow pots. Now (most) CD-Rs work and it hasn't skipped yet. One CD-R just refuses to work, but another burn of the same CD plays so it might just be a bad burn (though everything else plays it fine).

  14. #14
    Raging in the Streets Blades's Avatar
    Join Date
    Dec 2006
    Posts
    2,920
    Rep Power
    70

    Default

    Actually, CD-Rs skip badly towards the outer edge. I look forward to seeing what happens with the new laser (which should arrive from China in a month or so).

  15. #15
    Hedgehog-in-Training Hedgehog-in-TrainingWildside Expert
    Join Date
    Jun 2015
    Posts
    163
    Rep Power
    4

    Default

    I'm not entirely sure how to tell which ones are genuine or not, even in stock machines I've never seen a laser with yellow marks on the pots. By the way, adjusting the pots to the same values as another laser won't necessarily give you the same results. The whole point of having pots on there as opposed to fixed resistors is because each unit's optimal values differ from unit to unit, that's why in order to properly adjust the pots you need a scope and the correct test CD. It's not a case of one set of resistance values works for every machine, it's that there are a set of optimal scope values that need to be set, and the amount of resistance needed for that is different for every machine.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •