Garbage on screen

If you're making a portable you probably need something to watch it on. (Unless you want to guess what's happening in the game, but I wouldn't advise that) Anyway, this forum is your "Hacking a pocket TV/screen" one-stop solution. Share your experiences and knowledge here.

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maxi
Posts: 5
Joined: Fri Oct 07, 2011 6:42 pm

Garbage on screen

Post by maxi » Sat Dec 17, 2011 10:39 pm

Hello,
I'm doing a portable Master System (which, with a little of luck, I will post here when it's over :P) and just made the A/V connection on my Optimus Pocket Color TFT LCD TV. The sound is functioning normally, but the video is full of strange characters on the screen. You can see some "scroll" of the game when it is running.
I saw on http://portablesofdoom.org/page.php?page=sms" onclick="window.open(this.href);return false; that you can use some capacitors to amplify the signal, but since on a normal TV the A/V mod is working normally and also is the sound on the pocket TV, I don't think it's the case.
Does anyone know what might be happening?
Thank you very much.

tom61
Senior Member
Posts: 1517
Joined: Fri Mar 25, 2005 6:51 pm

Re: Garbage on screen

Post by tom61 » Tue Dec 20, 2011 6:48 pm

Strange characters are a problem with the console most likely, probably either a voltage issue or the cart and slot needs cleaned.

maxi
Posts: 5
Joined: Fri Oct 07, 2011 6:42 pm

Re: Garbage on screen

Post by maxi » Wed Dec 21, 2011 5:41 am

Thank you, but the console is still running with the normal power adapter and the TV with the batteries (however, I already put the white led mod and desolder the TV tunner).
And the game is the "built in memory" version of Sonic, so it is running without any cartridge.

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armarares
Posts: 69
Joined: Thu Jul 28, 2011 6:48 pm
Location: romania

Re: Garbage on screen

Post by armarares » Wed Dec 21, 2011 10:57 am

Try it on a TV first.
I never give up. But I always fail.

maxi
Posts: 5
Joined: Fri Oct 07, 2011 6:42 pm

Re: Garbage on screen

Post by maxi » Wed Dec 21, 2011 12:51 pm

As I said, on a normal TV the A/V mod is working normally. Also was the pocket TV channel signals before the removal of the TV tunner.

tom61
Senior Member
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Joined: Fri Mar 25, 2005 6:51 pm

Re: Garbage on screen

Post by tom61 » Wed Dec 21, 2011 9:32 pm

Pictures needed to continue troubleshooting.

maxi
Posts: 5
Joined: Fri Oct 07, 2011 6:42 pm

Re: Garbage on screen

Post by maxi » Fri Dec 23, 2011 6:06 am

I'm trying very hard, but all I get with my f* cam are photos and videos showing the TV working with a black screen. :evil:
Enlightenment is not enough for her to capture the image, but I'll keep trying or get another camera with someone.

tom61
Senior Member
Posts: 1517
Joined: Fri Mar 25, 2005 6:51 pm

Re: Garbage on screen

Post by tom61 » Fri Dec 23, 2011 6:59 pm

I see you're using some sort of translator, so I'm thinking that 'characters' is not the word you meant. It seems likely that you just meant a scrambled screen, which is likely caused by the values of the capacitors not being exact. LCD screens require higher precision for what they receive in input than a normal TV. You need to replace the fixed value capacitors with variable capacitors where the middle is where the desired capacitance rating, so roughly twice the value indicated for the highest value of the variable capacitor. Adjust the capacitors to the indicated value in the diagram using a multimeter to measure, install them, then make small manual adjustments afterward to get the image stabilized.

maxi
Posts: 5
Joined: Fri Oct 07, 2011 6:42 pm

Re: Garbage on screen

Post by maxi » Sun Feb 05, 2012 1:35 pm

Success!
I used similar schematics of the nes (those on the book) and it worked. Now I just need to figure out how to convert the signal from Pal-M to NTSC, because the console is brazilian and the TV is american, so the screen turns only black and white.

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