Technical and Repair Assistance

[133MHz]

Do you have any game cartridges to test your Famicom? You can use a Sega Genesis Model 1 or a TurboGrafx16 power adapter to power up the Famicom (or any power supply with a 9V DC center negative output).

[lasersamurai]

No, I don't have a single game, I almost got one or 2 at the flea market but I didn't i'll try the thrift store or the flea market for some next week. 

[cubelmariomadness]

I don't know if this is completely famicom related. I have a clone which worked fine until today. I took it downstairs, unplugged the av cords, and tried to play, and now the audio is a loud buzzing noise over the regular audio. Is there something wrong? I already tried new av cords.

[UglyJoe]

Does the clone have a microphone?  If so, fiddle with the volume slider (or, better yet, take apart the controller and clean the volume slider contacts) and see if makes a difference.

[cubelmariomadness]

Nope. No microphone. I am thinking some contact is loose inside.

Does anyone have any ideas. It was when I moved it from the tv upstairs, to the downstairs one. I unplugged the av cords, plugged back in, and an annoying buzz is behind most games.

[133MHz]

Does it happen on both TVs now? If it only happens on the downstairs TV, that one could have ground loop issues.  Most of the time buzzing audio from a Famicom means that the AC adapter is going bad.

[cubelmariomadness]

Really? Ac adapter? Well, it does happen on both tvs now. I guess i'll try swapping the ac adapter. Thanks.

EDIT: I didn't work even with a genesis adapter either. 

[133MHz]

Loose solder joints on the RF modulator board, or a dried up main filter capacitor. Clones aren't notorious for great hardware design.

[cubelmariomadness]

So there's no real easy fix? I am an idiot when it comes to a soldering iron. 

[133MHz]

Unfortunately not. OTOH reflowing cold solder joints and replacing large electrolytic capacitors is easy with basic soldering skills.

[cubelmariomadness]

One last weird fact. When you unplug the audio, the video goes away too. Is this supposed to happen?

[133MHz]

No. This means that the solder points for the RCA jacks are loose or the jacks themselves are really old/dirty, because the ground connection on the Video jack isn't making proper contact.

[cubelmariomadness]

Is there a quick fix to that either? Should I just clean the jacks, then check if the're loose on the inside or not?

[133MHz]

Yes indeed. Clean them with a mildly abrasive sponge if they're not shiny, scrape the inside connection with a small screwdriver or similar pointy object and if you find that their internal solder points have loosened, just apply some fresh solder on them and that's it.

In fact resolder them even if they seem fine to the naked eye, bad soldering can develop hairline cracks.

[cubelmariomadness]

Ah it didn't work. Now the front's side is loose!! Bah, I'm just giving up on this thing. Tis a shame I got it for christmas.