GUIDE: AV mod your Famicom

Discussion in 'Modding and Hacking - Consoles and Electronics' started by Da Bear, Dec 20, 2013.

  1. Pingaloka

    Pingaloka Newly Registered

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    Hi guys, my first post here.
    I'm trying to mode an HVC-CPU-GPM-02 Famicom using the following tutorial:

    http://jpx72.detailne.sk/modd_files/fc/avmod.htm

    But I get no video output.
    Here are some pictures of my mod. DO you guys see anything weird?

    [​IMG]

    [​IMG]


    BTW I'm using a 9v 1200A negative centre Power Supply with an Everdrive cartridge.
    The everdrive cartridge seems to work as it has a led that turns on which tells me that the console is also on.
    Tried it on my projector as well and nothing. I have Famicom 3 boards, tried doing this mod in all 3 of them and nothing.
    I'm thinking and thinking but can't find my error...
     
  2. dc16

    dc16 Dauntless Member

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    I wonder if attaching the 150ohm resistor to the 5V line is riskier than attaching the 300ohm resistor according to console5's design. On one of my Famicom, running on a original Genesis AC adapter, I noticed that after a prolonged period of time, I would get some graphical corruption. Or is that related to a well known glitch related to pre-198x Famicoms?
     
  3. nilats

    nilats Site Supporter 2014

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    I'm not expert but that capacitor on the bottom of second picture looks like it is touching that plane via the solder point on the right? I'd throw some electrical tape or something under it just to make sure it isn't.. additionally the wire looks close in same picture angle doesn't do it justice so it might be fine but I'd insulate it as well. I am not familiar with the mod personally but it says to cut the trace from line 21.. I see one cut at bottom of image 2 don't see the other just making sure you did it. Also on closer look on image 1 the transistor is it resting on the chip or the resistor under it? those could be causing shorts. I'd check those things first
     
  4. Da Bear

    Da Bear Active Member

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    No, you'r not missing anything. I have just filled the empty holes because I think it looks better, nothing else. :)
     
  5. Da Bear

    Da Bear Active Member

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    It "gets better" with copper foil. Make sure to solder for example a cut off component leg (or a wire) between the copper foil and ground.

    Copper foil does not remove all jailbars but it helps to reduce them. No need to remove the PPU if you'r careful when sliding the foil under the PPU.
     
  6. Da Bear

    Da Bear Active Member

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    Sorry for not following up on this thread but IRL gets in the way unfortunately.
    I still want to make a tutorial for the newer Famicom motherboard but I have not had time.

    Edit:
    Regarding Jail Bars, it's a construction flaw in the hardware. Even the NES have them but less noticeably for the eye - but with an oscilloscope you can see them.
    The only way for a perfect image is the NesRGB kit.
     
    Last edited: Mar 8, 2016
  7. Madao64

    Madao64 Newly Registered

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    Hey guys, just wanted to ask some questions since the 2 famicoms I AV modded seem to have problems.

    The first one I did resulted in a perpetual pink screen, along with the rare occasional cyan and purple.
    http://m.imgur.com/a/AL458

    The second one was more consistent though. A beige screen when nothing is plugged in, and a white screen when a game is plugged in.
    http://m.imgur.com/a/mvikT

    The game tested was 8BIT MUSIC POWER.

    Any ideas how I can fix these? Or what the problem is?
     
  8. wilykat

    wilykat Site Supporter 2013

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    Got a different game to try with or tried your game in a different working Famicom? A dirty or bad cart could cause blank screen.
     
  9. Madao64

    Madao64 Newly Registered

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    Will try.... Problem is I don't really know what to expect when looking for a blank screen. Everyone just shows videos of them in action but nothing about it when they're not switched on....
     
  10. Madao64

    Madao64 Newly Registered

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    Alright! Got another cartridge and tested it out, perfectly working!
     
  11. marcus600

    marcus600 Newly Registered

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    Hello , first post here ,
    my english is prety poor , but i tryed to doing the Av mod from DA Bear and thx for him ;) , but that's not work , i maybe did something bad

    I tryed to do exactly same , exept i had only 220R resistor , but i think that not big deal.

    my RF board was not exatly same for sur.

    Here the video of the probleme



    Here the pics

    mother board :
    [​IMG]

    mother board 2 :

    [​IMG]

    Rf board , i desolded all asked , but in some pics i can see some ppl didn t desolded all i did ??
    [​IMG]
     
  12. nathanmorrow

    nathanmorrow Newly Registered

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    I followed this tutorial but can only get a jumbled mess of pixels. The audio works fine but no picture.
    Here's some photos of the board https://imgur.com/a/NMRni
    My soldering was a bit rough but it all has continuity. I didn't have a 120R resister so I used a 100R and 22R which should be fine. I'm in Australia so my TV is PAL but it does recognise NTSC devices.
     
    Last edited: Jan 15, 2017
  13. AtomizerZero

    AtomizerZero Intrepid Member

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    You used 100K and 22K? That's not the right values is it? Check it again.
     
  14. nathanmorrow

    nathanmorrow Newly Registered

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    Sorry that was a typo, it is the correct value.
     
  15. AtomizerZero

    AtomizerZero Intrepid Member

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    Alright, well the only things i noticed on your images is that your RF box is layed out a little differently (and it probably doesnt matter, but you solder the cap at the wrong holes... try soldering it to the same place as the guide anyway. never know lol) and that the cap you used on the ppu is only 10v (16v or higher is recommended.)
     
  16. nathanmorrow

    nathanmorrow Newly Registered

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    Yeah I know, the holes it's meant to be soldered to are a bit wrecked but it's all along the same circuit.
    I've got proper value caps on the way, I just used ones I had laying around from a previous project.
     
  17. marcus600

    marcus600 Newly Registered

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    what about me ? do you see problem ?
     
  18. Garrett Dickinson

    Garrett Dickinson Newly Registered

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    Sorry to reply to this thread a year later, but I'm having some issues getting the mod to work with my Famicom. I finished going through the instructions, and after initially booting a game, I found that audio works perfectly, but there's no video. I looked back over the instruction multiple times and am stuck as to what the problem might be.

    https://imgur.com/a/GaYfo

    The only problem I could think of would be the black solder point i messed up on the power supply board.
    The reason why the capacitor is moved up a spot on the trace is because the actual trace peeled off of the original hole, so I just cut it off and moved it up a spot.

    Any help is greatly appreciated!
     
  19. Ultron

    Ultron Spirited Member

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    It looks like the jumper you put in to replace R12 is not making contact on the top of the board (left side in picture). It also looks like the trace came off going from the left contact of the R12 spot to the emitter of Q1. From the pics, it looks like the whole trace came off the board, including the part for the through-hole, which is why the short is not making contact in the first place. No worries, it is fixable. Turn the board around, and solder a jumper wire between the two spots circled red in the photo. That should fix it.

    AV oops.png
     
  20. AndehX

    AndehX You got boost power!

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    I did this mod and it worked perfectly. Nice easy mod with no external circuits.
     

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