5" screens and some questions about powering them on a n64 board

Discussion in 'Screens' started by noh_mercy, Dec 1, 2017.

  1. noh_mercy .

    Joined:
    Aug 10, 2017
    Messages:
    8
    Likes Received:
    6
    Hey guys, I'm looking around for 5" composite input screens for my n64 portable. Preferably off amazon because prime shipping.

    Some I've come up with are:
    https://www.amazon.com/gp/product/B00CZ85YVU/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
    https://www.amazon.com/800x480-Fold...01GFFMRY0/ref=cm_cr_arp_d_product_top?ie=UTF8

    I notice that all of these small screens say they need 12 volts. Can they decently run off 7.4 volts as well? I also read somewhere on here that there are regulators inside that step the 12v down to 5v. Anyone know of what points I can solder to on the N64 board to get 5 volts to connect the screen to?
     
  2. Cradiak .

    Joined:
    Apr 27, 2018
    Messages:
    57
    Likes Received:
    13
    Location:
    Kentucky
    Portables:
    Wii Laptop V2.0
    I'm not too knowledgeable about the n64, but I looked up a pinout and didn't see a 5v supply on it. You can build a custom regulator or voltage divider circuit that should work fine for that. You just have to have to run a circuit in parallel with the 7.4V feed on the board and use resistors to split the voltage from 7.4V to 5V. Based on my limited knowledge of electronics, I believe that should work.

    Someone here can correct me if I'm wrong (and I might be). That being said, if the board on the lcd has a regulator to step down the voltage from 12V to 5V, it might work off 7.4V since it's still more than the 5V the lcd needs to run. The 12V is probably a limit (no more than 12V) rather than a requirement.

    I would go ahead and get one and try it first off 7.4V and see if it works before doing anything crazy.
     
  3. Gman RTFDS Staff Member . . . .

    Joined:
    Feb 25, 2016
    Messages:
    719
    Likes Received:
    1,409
    A voltage divider won't work for a voltage supply because the output will affect the voltage, known as the "loading effect". I would try the screen from 7.4v, that is correct.
     
    cheese and Shank like this.
  4. Shank Certified Wiitard Staff Member . . .

    Joined:
    Jan 31, 2016
    Messages:
    933
    Likes Received:
    1,661
    Location:
    Texas
    Portables:
    1
    N O P E
    I second what Gman says. Don't do this. Voltage dividers are for setting reference voltages, and should not be used on anything that has a load on it.
     
    Stitches and cheese like this.
  5. Cradiak .

    Joined:
    Apr 27, 2018
    Messages:
    57
    Likes Received:
    13
    Location:
    Kentucky
    Portables:
    Wii Laptop V2.0
    Okay, thanks for the correction!
     
  6. Trozze .

    Joined:
    Jun 25, 2018
    Messages:
    12
    Likes Received:
    9
    Location:
    Sweden
    All screens I have used has accepted 7.4 volt with no issues. The switching IC can usually go as low as 6volt.
     
    Last edited: Jul 4, 2018
  7. E64 .

    Joined:
    Nov 15, 2016
    Messages:
    67
    Likes Received:
    21

Share This Page

Loading...