Hi all, I've done the Famicom AV mod but I always get a garbled screen when trying to turn on the console. However, the sound is fine.
Details: I don't know which kind of model is the Famicom cause the back of the console shows it's HVC-002 and the box shows it's HVC-001 (I suppose that it's a HVC-002). The board shows the next kind of CPU: HVC-CPU-07:
(http://i39.tinypic.com/a9ws9.jpg)
I've tried 4 different mods and only works these with the same result: garbled screen.
1. http://www002.upp.so-net.ne.jp/jsrc/densi/fcav.html (http://www002.upp.so-net.ne.jp/jsrc/densi/fcav.html) -> But I use a 4,7uF capacitor instead of 0,47uF as suggest in this website. The transistor I use is NPN 2SC1815 as suggest this website http://www.briconsola.com/esp/p23.htm (http://www.briconsola.com/esp/p23.htm) (and the same site too).
2. http://nfggames.com/forum2/index.php?topic=4055.0 (http://nfggames.com/forum2/index.php?topic=4055.0) -> I use a 3x300ohm in serie, and 82ohm the other resistor. It just works like the other mod: garbled screen.
The 2 mods I've tried that it didn't work are:
3. http://www.briconsola.com/esp/p23.htm (http://www.briconsola.com/esp/p23.htm)
4. http://old8bits.blogspot.com.es/2013/03/famicom-mod-av-para-el-modelo-esquemas.html (http://old8bits.blogspot.com.es/2013/03/famicom-mod-av-para-el-modelo-esquemas.html)
I tried to change the transistor to a BC546 but with this It didn't work (it shows black screen).
I don't know where can be the problem (maybe PPU ?). I've been researching in some forums but I can't find the solution.
Pictures (The game is Rockman 5, but I've been trying with Double Dragon II, Ninja Ryukenden, Punchout with the same results):
(http://i44.tinypic.com/33l12fc.jpg)
(http://i43.tinypic.com/300ckfb.jpg)
(http://i43.tinypic.com/9k5z48.jpg)
Picture of the mod (it can be confuse but I REALLY follow the next scheme)
(http://i41.tinypic.com/akaaro.jpg)
(http://www002.upp.so-net.ne.jp/jsrc/densi/famicom.gif)
Video:
View My Video (http://tinypic.com/r/73e61g/5)
Thank you in advance !!!!
Be sure, that slot is clean. This graphics issue has nothing to do with video circuitry.
Quote from: 80sFREAK on May 06, 2013, 04:59:27 pm
Be sure, that slot is clean. This graphics issue has nothing to do with video circuitry.
Hi, thank you for your advice but how could I know if the slot is clean ? I've cleaned the cartridges but I don't know how to check if the slot is clean or not.
Post Merge: May 06, 2013, 05:38:12 pm
I've tried to clean as it suggested here, but it doesn't seem to work. There's the same f******* garbled screen :(
http://www.youtube.com/watch?v=bWg2k736KZ4
if you checked the slot connectivity there is definitely something wrong with CHR part. Try to check decoder and SRAM
Quote from: famifan on May 07, 2013, 02:11:39 am
if you checked the slot connectivity there is definitely something wrong with CHR part. Try to check decoder and SRAM
Hi, I've checked this PDF http://www.benheck.com/Downloads/NES_Famicom_Pinouts.pdf (http://www.benheck.com/Downloads/NES_Famicom_Pinouts.pdf) to identify the CHR's points and I think I know where are all these pins ... but I'm sorry, What have i to do now whis this pins ? Thanks.
It's strange that all your games have the exact problem so you might want to check your Famicom as well. Begin with a continuity check with a multimeter between these and other points.
Quote from: P on May 07, 2013, 11:39:01 am
It's strange that all your games have the exact problem so you might want to check your Famicom as well. Begin with a continuity check with a multimeter between these and other points.
Ok, I'll begin now with my tester. I'll notify you when I finish.
Post Merge: May 07, 2013, 02:20:53 pm
All is OK :S I don't know where can be the problem ... maybe the PPU is blown ?
I'm experiencing the same issue, did you ever figure this out?
Quote from: Gippy44 on January 30, 2017, 09:42:25 pm
I'm experiencing the same issue, did you ever figure this out?
i got the system with the same issue too.
http://www.famicomworld.com/forum/index.php?topic=12651.0 (i pucrhased the system from that thread)
i'm going to get UMC drop-in replacement for PPU fro aliexpress just like http://www.famicomworld.com/forum/index.php?topic=13029.0