Is there a Place to Solder a Drive Access LED on a Ps1?

Discussion in 'Modding and Hacking - Consoles and Electronics' started by MightySubzero, May 21, 2016.

  1. MightySubzero

    MightySubzero Rising Member

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    Is there a place on the ps1 motherboard .. I'm thinking of adding a Access LED to the ps1's I sell. if there is one... haven't found much of anything online about it.
     
  2. supersega

    supersega Beff Jr.

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    You might be able to put one on the seek motor?
     
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  3. Unseen

    Unseen Spirited Member

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    Another candidate signal would be the one that turns the laser diode on, it's called LD_ON or LDON in the schematics in the service manual. It should be available on the mechacon (seems to be IC304 pin 49 in all schematics I just checked) and RF amplifier (likely IC 723, pin 11) chips. 3.3V logic signal, no idea if it could reliably drive an LED without a buffer.
     
  4. MightySubzero

    MightySubzero Rising Member

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    great thanks for all the help.. will try and see what I can come up with....... will post results once I have done it later today.
     
  5. wilykat

    wilykat Site Supporter 2013

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    Probably best to use a transistor rather than to try a drive LED directly. LED anode to power rail, cathode to current limiting resistor then to collector of NPN transistor. Base of transistor through a resistor, something like 10k to the LDON pin of the chip. Emitter of the transistor to ground.

    The LED current limiting resistor depends on which LED you use, red, amber, yellow, and green typically needs 1.8 to 2v while blue and white needs closer to 3v. Also depends on where you tap for power, if you tapped 5v you need higher resistor value than from 3.3v
     
  6. ASSEMbler

    ASSEMbler Administrator

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    I think you'll need to make a schematic :p
     
  7. citrus3000psi

    citrus3000psi Member

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    Here you go. The 82 Ohm resistor assumes the LED is 1.2 volts and will pull 20ma

    [​IMG]
     
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  8. MightySubzero

    MightySubzero Rising Member

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    thanks a lot. for the help..
     
  9. lordnoc

    lordnoc Newly Registered

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    Please post a video, I'm very interested in this mod and I'd like to see it in motion.
     
  10. TriMesh

    TriMesh Site Supporter 2013-2016

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    Unfortunately, I don't think this will do what you want - the LDON signal is going to be active whenever the disc is spinning even if the drive isn't reading any actual data. The only time it will turn off is if the game stops the drive, which is something that most PlayStation titles never do.
     
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