Hello all. Before I begin, I must apologize in advance for any grammatical errors in this post, all of my posts in fact, since English is not my first language (plus it's also very late right now where I live).
I just recently AV modded my Famicom and was also able to successfully increase the length of the controller wires. Everything seems to be working just fine in these aspects.
I am occasionally encountering an issue with my Famicom however. While I'm playing a game, it seems that the picture tends to "flip-out" or "shake/stutter" and along with that, gets discolored sometimes for a brief moment but everything seems to work just fine after that occasional stutter. I was wondering what may cause such odd behavior. I hope I am able to accurately describe this issue in words since it is almost impossible to take a picture of it at the right moment, unless I film gameplay and the issue is reproduced, since its occurrence seems to be random.
The motherboard I have says (c)1984 and I believe it is the "HVC-CPU-07" revision. Is this a known issue in the original Red-White Famicom and is considered perfectly normal? Is it possible that I have a dying PPU or something to that effect? I am located in North America and am using 110 V to connect my Famicom instead of the 100 V Japanese standard if that helps. This issue has been present from even before I performed the AV mod.
I would like to know your insight and opinions as to find out why exactly this is happening.
Thank You!
There are couple different mod schematics, it might be a mistake somewhere or some component you used is maybe not the highest quality, capacitor etc. That being said, I modded mine by using the cheapest capacitors I could possibly find on eBay. It could also be faulty component somewhere. Have you tried different TV's? I havent't done the controller cable mod so I don't what that involves and how it can or if it can affect overall stability of the console. We have 220V power system here, unless the power adaoter is very poor quality it shouldn't cause any problems since as long as the console gets proper power all is OK. I use 9V 1A power adapter and again the cheapest I found.
hi.
apart from the temporary and occasional disturbance of the picture, did the issue affect anything else?
i doubt it is related somehow with the AV modding itself.
it seems more like connection issue in any moving electrical parts of the famicom. It could be even worn-out internal mechanism of the main power switch of your famicom. Other than that, it could be broken wires which power up famicom: ac adapter cable, ac adapter connector, ac adapter socket on famicom PCB, internal wires that lead to the power switch.
i think you have experienced the following issue on your famicom: for some reasons, especially improper mechanical contact somewhere, the main power gets interrupted for a very short period of time just a couple of frames and the voltage gets down a little bit for a moment, therefore the analogous part of the famicom, say, PPU picture generator leads to the video signal distortion. For this short moment your TV couldn't recognize the color information or the frame itself, so you'll see the picture disturbance. But I may be wrong.
unless you be able to reproduce it, it's very hard to define the root cause of the issue.
i propose you to inspect all power cables/wires, power switch and power connectors. Any insulation cracks, wire bents, loose connector fitting and so on. Good luck!
I appreciate both of your replies. As stated above, this issue also existed when the Famicom was completely unmodded and using the default configurations so I too believe that it is not because of any modifications done to the system.
I managed to take a video of this issue while playing Nekketsu Kouha Kunio-kun and it seems that during the multiple attempts that I make to start level 1, it now seems to be ALWAYS glitching out but it is not discoloring.
Here is a link to the video: https://youtu.be/zYHJzE7qUU0
TMNT 1 (USA) gives me a similar issue without discoloration (the picture tends to 'move' to the lower right corner of the TV screen for less than a second. I have tried 2 different TVs with this Famicom and get the same result).
All the connections on the Famicom PCB seemed to be solid but I will need to open it up again to verify if that is indeed true. I personally did not see any issues with any of the wiring or such but I suspect there may be corrosion on some of the old solder somewhere that may be leading up to this although I don't recall seeing any.
thanks.
watched the video, as far as i can tell - this is the mechanical noise of improper electrical contact from the power switch.
could you try to push or touch slightly the power switch and see if the issue is being reproduced again?
Okay, I did what you suggested and it seems that it doesn't seem to do anything. The games seem to work perfectly fine while I'm messing with the power switch. I even brought it as close as possible to the off position but it continued to work fine and didn't show even the slightest hint of interference.
I will try using another power adapter on the console and see if this issue is replicated. The power adapter that I'm using seems to work very well with my NES Front Loader and Sega Mega Drive systems (both NA and JP regions) so I highly doubt it'd be the issue. I will try nonetheless in order to rule it out just to be safe.
that's sad :( it doesn't seem to be so trivial as i initially thought. please keep searching the root cause. i don't have any other things in mind to suspect.
No problem. To be honest, I think I may be swapping this Famicom with a later revision motherboard (due to issues with EverDrive autosaves). Either that or get a junk unit sometime in the future and swap the PPU to see if it fixes the problem. I tried a different TV today and it started acting up at a different part of the game this time and not the part in the video which leads me to suspect that it could possibly be a PPU issue.
I won't be going the AV Famicom or the Sharp Twin route as this design is the most nostalgic to me as I had it (a Famiclone actually) instead of the NES where I lived as a kid ;D.
I appreciate all the help I have received so far. If anyone else has any possible solutions, please let me know so that I can try them out!
I've just finished a litany of mods, including the AV mod, and ended up with a similar issue. Just as with the original poster, it's pretty rare, but when it does occur distortions such as oversaturated colors and little "blips", like a line or two of static occur.
Near as I can tell, the power switch appears not to have issues, and nothing else cuts out. All I can add is I'm using a US to Japanese power converter which should rule out power differences being an issue. I do know that NTSC and NTSC-J do have some differences, so maybe that's got something to do with it?