Twin Famicom AN-505-BK display problem

[io]

Hello,

I have two Twin Famicom AN-505-BK (they are really twins ) and both are showing a moving picture while on my Famicom AV the picture is steady.

I have already replaced all capacitors on the power board of one of the Twin but the problem (if it's one) remains.

It is a know problem with a known solution or is it just a normal behaviour ?

Thanks for any reply.

io

[fredJ]

Hi, welcome.

I don't know what you mean by moving picture? I have no problem with this model or any other twin famicom...
In fact I have made a video on youtube I could show you, if you don't laugh at the bad picture quality...
Maybe you could try it on a different television? Never know if that it the problem.

[io]

It was like the whole picture was moving on the screen or being a bit deformed, like the picture was on a flag waving very slowly with the wind.

While I was cooking crêpes, I thought, maybe my step down voltage converter (220 V/50 Hz to 110 V/60 Hz), which is humming, is the cause of that.
So I tried with a good quality universal voltage adapter and all went back to normal, like with my Famicom AV.

Sorry for creating a topic for that, but maybe it will help someone else in the future

By the way, I have changed the belt on one Twin and it worked again without any adjustment. I think, because I did not totally remove the whole triangle with the gearwheels to replace the belt, I didn't lose the setting. I will try this method on my other Twin and some FDS to see if it gives good results.

[Terpor]

Does it look something like this



Post Merge: June 16, 2012, 03:27:19 pm

Does it look something like this

If you have AV Famicom, then could you take some in-game pictures from it? I would wanna see if it has better picture qualify than Twin Famicom.

[io]

No it doesn't look like this. I'll take photos to show what the problem looked like and some other to compare Twin display with Famicom AV one.

[Terpor]

Here's more  pictures
https://www.dropbox.com/s/0tun5g6giiw0d8d/amarec20120615-203503.bmp
https://www.dropbox.com/s/0tun5g6giiw0d8d/amarec20120615-203503.bmp
https://www.dropbox.com/s/ovgaj0zrri3aspo/amarec20120615-203600.bmp
https://www.dropbox.com/s/puovyzqnua17yiw/amarec20120615-203626.bmp

[Drakon]

That's called composite video.

[io]

Terpor : My problem wasn't a picture quality problem.
The image was nice and clear with the right colours, it's just that because of some electrical interferences caused by my step-down voltage converter, the whole image was dynamically lightly distorted.
I'll do a video if you want when I get back working on my Twin.

[famifan]

Terpor : My problem wasn't a picture quality problem.
The image was nice and clear with the right colours, it's just that because of some electrical interferences caused by my step-down voltage converter, the whole image was dynamically lightly distorted.
I'll do a video if you want when I get back working on my Twin.

it seems that input voltage to 7805 was less then 7V and you catch 100Hz or 120Hz pulse noise in the image. Noise frequency equals twice of your country AC frequency due to rectifier bridge. If input voltage to 7805 becomes more than 7V it will completely reduce that noise.

[80sFREAK]

it seems that input voltage to 7805

7805

Twin Famicom

[famifan]

it seems that input voltage to 7805

7805

Twin Famicom

kk

s/7805/discrete voltage regulator circut/g

anyway, the reason was right, but some details were wrong