Dreamcast: Dead Laser?

Discussion in 'Sega Dreamcast Development and Research' started by Everblue, May 14, 2013.

  1. Everblue

    Everblue Spirited Member

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    Today I received a US Dreamcast bought as working from Ebay. Unfortunately it is not working as it should:

    Original US game: disc spins and spins until it gets to a halt
    Verified backup: same as above
    Music CD: same as above

    What are the chances of the problem being a bad laser?

    If it helps, the model is HKT-3020.

    Thanks!
     
    Last edited: May 14, 2013
  2. cybdyn

    cybdyn Embedded developer (MCU & FPGA)

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    if it spins few seconds or more - it means the laser is not fully dead. maybe something wrong with sledge mechanism. carefully try move HEAD a little from center by finger. (dont touch lens!!) and then you switch power ON and close DOOR it should be moved to the center.

    next: maybe lens is dirty.
     
    Last edited: May 14, 2013
  3. Everblue

    Everblue Spirited Member

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    Hi there, thanks for your reply... I tried that and the head went back to the centre. It still won't read the disc though, it sounds like it is trying to read but cannot focus on the disc (which keeps spinning for around 10-20 seconds) or something (hope it makes sense!). Any other suggestions are welcome!
     
    Last edited: May 14, 2013
  4. -=FamilyGuy=-

    -=FamilyGuy=- Site Supporter 2049

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  5. Everblue

    Everblue Spirited Member

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    Thanks a lot!
     
  6. TriMesh

    TriMesh Site Supporter 2013-2017

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    Another thing to check (especially if this is a unit that's been in storage for a long time and worked when it was put away) is that the gear train that drives the optical pickup sometimes jams, and this will result in the disc just sitting there spinning trying to read the TOC. When you operate the door switch, the optical pickup should move right to the center of the disk and then move out again slightly - if it's seized, you can often free it up just by manually turning the intermediate gear on the assembly (the one that meshes with the gear on the motor pinion).
     
  7. Guaripolo

    Guaripolo Spirited Member

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    1) try a lens clean.
    2) check if the laser do a "click" sound.
    3) check the laser red light. Do it watching from the side, DO NOT look from top of the machine.
     
  8. Everblue

    Everblue Spirited Member

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    Ok I did the following, still doesn't work:

    - looked to see if I can see the red laser, I couldn't see it
    - put the laser to the edge, when I closed the lid it moved to the centre and stayed there, I don't think it went slightly back again, hard to notice with a closed lid
    - cleaned the lens gently with a cotton swab, did nodifference

    Dont want to open the console yet as I has been sealed by the seller and I am waiting for his reply on what to do.
     
  9. cybdyn

    cybdyn Embedded developer (MCU & FPGA)

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    as you say - "it sounds like it is trying to read but cannot focus on the disc (which keeps spinning for around 10-20 seconds)" - i think laser is "red"))) but lens is dirty. another problem is laser head's cable. also laser need some more power - so it need rotate clockwise power resistor on head
     
  10. cybdyn

    cybdyn Embedded developer (MCU & FPGA)

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    also - the disc motor is offten gets broken and cant get speed up properly.
     
  11. Everblue

    Everblue Spirited Member

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    I think the best option is to return the Dreamcast to the seller and get another one as he offered this. Meanwhile I would like to thank you for your help and I look forward for the completion of the GD-Rom emulation project. Any dates yet on when we can buy one? Thanks :)
     
  12. Everblue

    Everblue Spirited Member

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    Some good news, the seller told me not to worry about it much as he is sending me a replacement console.

    Meanwhile, I tried to fix it by turning the pot a bit - but it did not solve the problem. If I buy a complete CD unit replacement for it (around 15USD from HK) what are the chances that it would be fixed? Does it matter which CD Unit I get (Samsung, Yamaha?)?

    Thanks!
     

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