av mod famicom problems...only black and white

Hi guys ,
I hope you can help me because I think I have a Famicom with the ppu bad since I took pictures of the changes made. The picture and sound are very good but unfortunately we see black and white yet tried it on multistandard television and I try to bridged to test various points but alas nothing did the color you see for a second nn but remains fixed for nothing ... I also found a diagram of the ppu on nesdev wiki where I noticed that the pin 18 relative to the clock CLK can be of great importance for the solution to my problem:
The site explains the various points
http://wiki.nesdev.com/w/index.php/PPU_pin_out_and_signal_description
Since I keep a pal nes fault according to you if you use a slot for 40pin chip so as to exchange various ppu can be a solution? The only doubt that the ppu a pal nes could create me problems glitches in various games among jap like castlevania 3. You say that it can depend on that or do I withdraw with other schemes am blessed color?
I know it is very difficult and I hope you can help me ... d the other hand, this is my first edit on a Famicom nn then I was able to make the previous ....
Thank you and see you soon!
Mr. Forever

i report my mod and the schemes that i've tried but without success :-(

 

I'd recommend using this schematic for an AV mod for the Famicom:



I used this for mine and it's a really good solution. I desoldered the Q1 transistor, and put in a different NPN transistor on the under side of the board and then followed the schematic, since I really can't make heads or tails of exactly what you've done here.

Hope this helps.

 

Try to change the clock crystal to a new one. It's probably out of sync, not very common but it happends from time to time.

 

you mean this?
specifications? values?
thank you

 

No, in the bottom left corner of this image - just below the green variable capacitor is the clock crystal.
Replace with the same value, e.g 21.477272 MHz and you should get color.

 

infact i've tried to trim it but without happened it doesn't give any effect...so you tell me that i should replace it and solve my problem? i will desolder it and replace with one new right?
Thank you
Mike

 

Exactly, you can get one from a broken NTSC NES if you can't find new ones.

 

thank you but i live in italy and i ask on electronic store but they don't have clock crystal...can you tell me a website where i can found it? because if i will buy a broken nes american or famicom is expensive for me...
thanks you again, best regards mik

 

problem solved!! changed clock crystal and i get colors!! .-D thank you to all!!
bye
Mik

 

Just to let you guys know, X-RAYS from package scanning at mail or airports can cause serious damage to quartz oscillators.

 

Might explain why some of my overclock mods using oscillators have mysteriously died in transit.

 

It's weird that oscillators would be affected by x-ray given they're contained in metallic packages and the crystal itself shouldn't be too much affected by the x-ray... Maybe there's some small gap the light can find its way in and break something else than the crystal itself... For extra caution one could wrap them up in metallic tape...

 

Not weird at all considering the strength of the x-ray scanners they use to look for drugs these days. Blame it on drug dealers and smugglers and maybe Al Queda for it.

 

I blame paranoia and violation of the fourth amendment.

 

Well, from a solid state physics point of view, there's no way the x-rays are powerful enough to break the crystals. I guess it breaks some stuff around by inducing small but high current spikes.

 

Hello, I have the same problem but don't know where to find those oscillators.
Does anyone have any idea where to find one of them?

Thank you.

 

It doesn't break the crystal. It knocks out a couple of atoms on the crystalline lattice causing the resulting frequency it oscillates change.

 

Im also looking for an xtal replacement 21.477272 also posted in wtb section. thanks