Sega CDX PCB Component Rotted

Discussion in 'Repair, Restoration, Conservation and Preservation' started by onza120, Nov 12, 2017.

  1. onza120

    onza120 Site Supporter 2014

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    Hello all

    Due to there being no service manual for the CDX I'm having to ask for help identifying this component on the laser PCB, I'm hoping it's just a basic fuse I can bridge but want to make sure first, the component in question is 16.9C42

    Thanks in advance!
     

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  2. DeChief

    DeChief Rustled.

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    Looks like an oscillator crystal to me, but I don't know anything about reading their labels. @TriMesh might know.
     
  3. onza120

    onza120 Site Supporter 2014

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    Thanks for the reply, I wonder if a 16mhz Crystal Oscillator would work? Yeah there isn't much @TriMesh doesn't know :p
     
  4. LeHaM

    LeHaM Site Soldier

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    Yeah IIRC X is used to designate crystals (XTAL)
     
  5. onza120

    onza120 Site Supporter 2014

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    Does anyone know if a 16MHZ Oscillator would work?
     
  6. Bad_Ad84

    Bad_Ad84 Keyboard Error: Press F1 to Continue

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    I think its a 16.9Mhz not 16Mhz.
     
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  7. Taijigamer2

    Taijigamer2 Robust Member

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    Definitely a 16.9mhz crystal. I would desolder it and clean up the through holes to assess damage. If the points are too far gone, there seems to be some vias directly linked to the through holes which u could use as alternative solder points. The oscillator may still work, it might just be a corroded connection.
     
  8. LeHaM

    LeHaM Site Soldier

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    Has no one reversed engineered this board even a little?
     
  9. eb1560

    eb1560 <B>Site Supporter 2014</B>

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    That is a 16.9 MHz quartz crystal (HC49/US), though highly unusual that it is floating that high off the circuit board. The closest crystal you will commonly find is 16.93 MHz on most online electronic distributors (likely the exact part). You may want to verify if there is a tiny capacitor on each of the two traces connected to that crystal (check opposite side of the board) - if there are no capacitors then the crystal with the lowest ESR and better frequency stability is the optimal choice.
     
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  10. TriMesh

    TriMesh Site Supporter 2013-2017

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    The theoretical frequency is going to be 16.9344MHz - it's a standard frequency for the reference clock on CD players using a 24 bit output format. It's 4 times the output bit rate (44.1kHz * 2 channels * 24 bits). Most of them are listed as 16.934MHz, and typically those HC49/4H package xtals have a 20 or 30pF load capacitance.

    Edited to put the correct result in :)
     
    Last edited: Nov 15, 2017
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  11. onza120

    onza120 Site Supporter 2014

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    I’m going to try a re-solder and will also report back on the possible capisator on the traces
     
  12. onza120

    onza120 Site Supporter 2014

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    Re-solder to no avail, still stuck on "checking disc" and stays that way until the disc completely stops. Seems to be capacitors on the traces yes.

    Does anyone know a compatible oscillator?

    Thanks for all the replies
     
  13. TriMesh

    TriMesh Site Supporter 2013-2017

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  14. onza120

    onza120 Site Supporter 2014

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    Last edited: Nov 14, 2017
  15. Taijigamer2

    Taijigamer2 Robust Member

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    Have you cleaned the corroded through holes and checked for continuity? Have u ruled out a failing laser? Do u have pictures of the top and bottom of the pcb near the oscillator and associated IC? It would be good to check the crystal with an oscilloscope just to definately rule it out.
     
  16. Oakleaf

    Oakleaf Rising Member

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    50pcs/lot Crystal Oscillator 18.9375MHz 18.9375 MHz 18.9375M Hz Mini Passive Resonator Quartz HC-49S
    50pcs/lot Crystal Oscillator 18.9375MHz 18.9375 MHz 18.9375M Hz Mini Passive Resonator Quartz HC-49S might work fine
    http://s.aliexpress.com/2M7NjARN
    (from AliExpress Android)
     
  17. Bad_Ad84

    Bad_Ad84 Keyboard Error: Press F1 to Continue

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    Those wont do much good.
     
  18. Oakleaf

    Oakleaf Rising Member

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    O sorry wron freq. But there is a lot of them on ali. Might be able to find one.
     
  19. TriMesh

    TriMesh Site Supporter 2013-2017

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    I just had a look, and I'm not having much luck - RS don't even stock this frequency, Farnell are only showing "US Stock" (I.E. Newark) and Digikey are about the same delivery cost as Mouser. If I think of any more possible suppliers I will get back to you.

    I could add the part to one of my Mouser orders and send it to you - but unfortunately I'm in Hong Kong and the only cheap shipping method would be (slow) regular airmail.
     
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  20. Bad_Ad84

    Bad_Ad84 Keyboard Error: Press F1 to Continue

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    You have posted a link to 19.6mhz, the original was 16.9.

    UK stock:
    https://www.ebay.co.uk/itm/CRYSTAL-...766913?hash=item3f88b906c1:g:7ukAAOSw7RdZ16Lk

    Or 20 from china:
    https://www.ebay.co.uk/itm/20-Pcs-H...854109?hash=item43e0b6535d:g:w1EAAOSwrP9Z1V0X
     
    Last edited: Nov 15, 2017
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