Hey Guys,
I am trying to mod this Famicom for AV, starting with audio, however, i can't get any audio from it.
With RF it's fine btw.
Pin 46 goes straight to the tip of chinch
and GND is taken from above.
I get about 2.5V at the chinch plug.
http://www.mediafire.com/view/s6p55c5c1nmffl7/20150401_170900.jpg
ANY HELP IS APPRICIATED !!!
Thanks
Have you tried different TV to test? Or just use another cable and cinch...
Does sound on RF work?
Yeah i tried different cables and tvs, but it worked on none of them. Sound on RF is fine
You could try to tap for separate audio channels on CPU pins 1 or 2
have you separated the signal with a capacitor?
No, i didn't try that, as i often heared it would work without a capacitor
Post Merge: April 03, 2015, 07:59:10 am
I didn'tt change anything since yesterday, but now the RF sound is much too high pitched on some parts, while othery sound perfectly fine !?! Capacitor failure ?
What capacitor do you have? What about polarity (plus minus)?
www.jpx72.detailne.sk/modd_files/fc/avmod/sound.png
But why is the RF sound wrong now i didn't solder anything !?!
Desolder everything you did, if the RF sound is still wrong, the problem is somewhere else. Maybe voltage regulator is bad, or you have bad adapter. Looks like voltage problem.
I desoldered everything. Sound is normal at startup, but gets disorted after some minutes of gameplay
Post Merge: April 04, 2015, 10:22:40 am
it cant be my power supply, as i use it on my av-fc without problems
Something must be overheating, can be CPU or RAM or... hard to say. Try the cheapest, exchange voltage regulator 7805.
Ok thanks. Gotta rob my nes for a 7805 :D
One thing, try to cut line from pin46 to the rf part and try cinch again. Maybe something on the small PCB, some failing capacitor (like mentioned earlier).
But what i can't get is that deep sounds soubd normal, only high ones get pitched
I had similar problem on a famiclone, high tones were too high, squeaky... exchanging CPU solved the problem.
If so, i guess i will leave it as it is, cause the famicom is only for collecting purposes
I found the problem. Its so dumb ..... my power supply was set to 12v . I now changed it to 7.5 and the problem is completely gone. Or would 9v be better ? I guess 7.5 is right at the limit what the 7805 can work with, but that means less heat i gues...
THANKS JPX FOR YOUR HELP NONETHELESS
Still your 7805 is going to die soon. By specs some are able to handle even 35 or 50 volts on input leg (with a huge heatsink).
Will i be fine if i replace it with a 2amps 7805 (only one i can find in germany) ?
Quote from: number47 on April 08, 2015, 08:40:17 pm
Still your 7805 is going to die soon.
Why should it? If it works ok now, it will work. Even with 7,5V.
Post Merge: April 09, 2015, 03:47:30 am
Quote from: jpx72 on April 04, 2015, 04:46:29 am
...or you have bad adapter. Looks like voltage problem.
...hehe
Quote from: number47 on April 08, 2015, 08:40:17 pm
Still your 7805 is going to die soon. By specs some are able to handle even 35 or 50 volts on input leg (with a huge heatsink).
Just FYI, the bigger voltage input, the more unstable(selfoscillation) working voltage regulator.
So now this problem is out of the way, has anyone an idea why i cant get sound via cinch ?
Have you tried everything mentioned?
1 only had 1uF capacitors at home, but shouldn't i have heard at least some kind of buzzing ?
Sound signal goes through pin46 to the RF part. If your RF produces sound, the problem is between famicom and TV.
Post Merge: April 11, 2015, 06:26:53 am
Oh important thing - your TV won't start to produce sound if it hasn't video input first! Start with video output and then audio.
But i can use it to get louder sound from my 3ds ?!? Anyway i gonna try the av mod today
Try it this way: plug anything (VHS, other console...) that produces video through composite cinch to the composite input of your TV - there are 3 female cinch holes, so use only the yellow. Take the pin 46 signal and plug it to the white or red. When your TV has video signal (any signal), it should also enable the audio input and you should hear it.
Maybe it's not your case, if your 3DS can be heard from your TV's composite input without actual video signal present. But it's worth a try.
Thanks i will give it a try the next time possible