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I tried to connect an old Japanese (NTSC, System M) video gaming system (an original Famicom, HVC-001) to a rather modern multisystem LCD TV-set (Sharp LC-43CFE5222E). The TV tuner is capable of tuning to the signal, but I can’t get both clear image and sound at the same time.

As can be seen in this video, the image is clear at 91.750 MHz. However, on this frequency the sound is not. If I use the fine tune control to adjust the frequency a bit higher to 92.125 MHz, the sound becomes clear, but image becomes distorted.

The game system has a channel switch with two options: CH1 and CH2. This problem happens on both of them, only the absolute MHz values are different.

Since I know only little about electronics, I would appreciate help finding the source of the problem. Is the game system broken? Is the TV tuner of low quality? Even if so, would it be possible to build a device that would shift the audio part of the signal this tiny bit?

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The problem is in using different standards for sending Video+Audio signal over RF. Basically any analog system uses the first carrier frequency to transmit video part and the second (shifted) carrier frequency to transmit the audio part.

I am not good to comment on particular standards; you can find this information in Internet. What you see looks like the frequency spacing between 1st carrier and the 2nd carrier are different in TX part (old gaming system) and RX part (TV). So you can get one (video or audio) component clear, but not two at the same time.

It is very difficult to fix by self-made means.

The easiest way is to dig into menu of your new TV set. May be it supports the standard you need. Then you are lucky.

Alternatively, you can look for a kind of media converter to convert the old standard to some supported by your TV set.

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  • \$\begingroup\$ Thank you, man! It looks like the console is using the NTSC-J standard, which is almost the same as NTSC-M. The only thing that differs is the audio carrier offset. The solution might be finding a Japanese analog TV tuner with any kind of video output. I’m still wondering, why it would be so difficult to build a one-purpose converter. It would demodulate the audio signal on a fixed frequency and modulate in back on a slightly different one. But I believe you that it is not so easy as it looks like. :) \$\endgroup\$ – Glutexo Apr 30 '16 at 17:31

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