Noisy Nintendo Color TV Game 15

Started by panzeroceania, December 30, 2010, 12:18:21 PM

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I have a Nintendo Color TV Game 15 system but it's providing an unusually noisy RF signal. I've seen other people on youtube with a lot less noise than me so I was wondering what I could do to minimize it.

I opened it up and adjusted some of the attenuators which helped a bit but doesn't really solve it.

I was wondering if there was a way to modify the system to simply output composite video and mono, or even S-Video, Component, RGB, etc. just to get away from the RF.

I know an RF signal can look good though from what I've seen from other people's Color TV Game 15 videos, as well as my own Atari Pong via RF.

It uses a Mitsubishi M58816P and M51342P chip.

It has paddle controllers that are wired into the system but actually detatch from the circuit board, as does the power cable.

here is a youtube video

Nintendo Color TV Game 15

here are a few pictures

Any suggestions would be great.


does anyone know the pinout for these chips?

Mitsubishi M58816P and M51342P chips.

I can't find anything on google.


I have the same console i got recently from Japan.
i too cannot find any information about the 2 chips on the motherboard.

Did you end up getting any information about them?

I am sure that composite video can be obtained from the M51342P chip.  We just need to know what the pinouts for it are and attach a simple amp to it.

Can anyone help with a datasheet for the 2 chips in question?  M58816P and M51342P?


I never got any info. A few sites listed the chip but didn't give any info.

I wondered if part of the problem is differing Japanese and American RF signals.

If this was the case, something like the Micomsoft DISPL TV might help things. Still, tapping straight composite, chroma Luma, or YUV would be ideal.

It more than likely only supports composite video and mono but even that would be an improvement.

Does anyone have any info?

How easy or hard would it be to try to measure the pins to find composite video? Is this possible? I've never atmpted anything like that and would need pointers. How dangerous would it be simply guess?


I'm not sure if this post will be that helpful, but thought i'd post the info I have found...

Firstly US and Japanese RF signals do differ in a number of ways. I cant find a good article that explains the differences but your best best it to search google for guides on a using a Famicom in other countries, since the Famicom also only outputs RF so you will find threads like this:-
Some of which may help you find a suitable way to use/convert the RF signal.

Also, I searched the part numbers you provided and found this Japanese site:-
Google translated:-
Which has a schematic of the Nintendo Color TV Game 6 and 15:-

From the schematic its clear that the M51342P is the video/RF modulator chip, so a quick search on google for "M51342P modulator" linked to this datasheet for the unrelated Mitsubishi M5C6847P:-
However, page 6 of the pdf has a pinout/example schematic for the M51342P which shows the video input pins. I also think if you try asking Mitsubishi's technical department for the full M51342P datasheet they may be able to help, since they appear to have scanned and converted to pdf most (if not all) of their old datasheets.

However there are a couple of problems I can see, firstly the video output pins from the M58816P are probably not designed to be able to directly drive a TV/Monitor, secondly from the datasheet I get the impression that the 'Video' signal is just Luma (Y) and not Composite Video, so any picture would likely not have any color as the color subcarrier is added by the M51342P. There are also R-Y and B-Y color difference inputs so if you have enough technical know-how you may be able to add a proper video encoder chip to give you RGB, S-Video and Composite Video outputs?

I hope this post at least gives you some ideas ;)


Thanks for the information Link,

Looking at the schematic I have the feeling that pins 2, 3 and 4 of the M51342P have something to do with the video and audio input.  I understand that it would not be ready to feed to a TV.  I wanted to a little amp to fix the signal ready for composite input.
Just need to determine what exactly these pins are and start testing with a basic amp to see if we can get any output.

Any ideas?


Glad to help :) Although you might want to look at page 6 of the datasheet I linked to, as mentioned previously it pretty much shows the entire pinout of the M51342P and confirms that pins 2, 3, 4 and 12 are all video related.


Look like pin 12 is the video input.
On that PDF they have a schematic for a video amplifier also.

I will steal the video signal from pin 12 and feed it into an amp and output it to composite on the TV.

Looks like Pin 15 is the audio input into M51324P chip going by the same schematic.

Think its time to start testing!!


I wish you the best of luck, but please keep in mind what I said above about the 'Video' signal - either it might not be a Composite Video signal, or it might lack the color subcarrier - so the picture probably wont have any color.


if that is the case the colour signal must be coming from somewhere.  Any ideas on which pin would be providing this?


Also one last thing.  I have a bunch of PAL 4.33Mhz crystals at home.  If i just replaced the 3.579Mhz crystal on the TV Game 15 would this generate a PAL signal VIA the RF?
I suspect it would but I really am only a hack.


I think you are misunderstanding - the M51324P chip adds the color subcarrier, thats why its connected to a crystal. You cant just connect some pins together to fix this. Sorry I cant help any more than that, i'm not an expert in this area and i'm only going off the datasheet and what it says about the video pins on page 2 (Which doesnt necessarily confirm what the actual output is of the M58816P, but given they use the same RF modulator chip the signals are more than likely the same)

<EDIT> Possibly, but why not contact Mitsubishi and ask for the full datasheet to confirm?


I'm at school now but will look at the datasheets when I get home.

The prospect of getting RGB or Component with enough know how and parts is exciting. Thank you!


No problem, I hope they help :)

Just thought i'd add that I found this circuit diagram which might help:-
Luminance (Y) and Color Difference (R-Y, B-Y) to RGB Video Converter:-
Three problems I can forsee are:
1) We dont really know what the video signal levels are, or what levels this converter is expecting.
2) It doesn't show how to strip the C-Sync signal from Luma, but I guess an LM1881 might help?
3) I have no idea if the 'Chroma Bias Ouput' (CHB) signal needs to be used.

According to this page where I found the original pdf link (Now dead):-
There was also another circuit design for a 'Luminance (Y) and Color Difference (R-Y, B-Y) to Composite Video Conversion' named "Vcckts.pdf", but I dont think this pdf is still available online.


Couldn't a S-video modification be done on this?
This looks similar to how the Atari outputs its video signal.  i would suspect that we would need to amplify the Luminance and colour difference signals and them feed them to a Chroma and Luma on S-video.

I am going to have a play around with my console and see if I can get any picture.


it's now possible to get composite video. an s-video mod is certainly possible as well with slight modifications to the instructions on nesdev.

to get s-video one would have to disconnect the luma input from the modulator chip and buffer it. i believe this will allow you to get chroma only out from the modulator.