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[drk421]

I think its a simple matter of the circuit being different.

When I have some time, I will "draw" out the schematic in simplified form from the PPU to the composite output.

My guess is that just "buffering" the PPU output with an emitter follower isn't enough. There might be some filtering going on.

[Great Hierophant]

Using the circuit from these schematics should work unless there are errors in it:

http://64.53.95.207/schematics/schematics.html

[Movax]

I see a couple errors after only a minute of looking at it.

Pin 37 and 65 on the cart interface are swapped. I'm pretty sure Char ROM Enable (pin 37 on there) is not connected to the system clock. Somethings not right about the Clock signal line, connected to pin 35,36,39 instead of ..well - the clock.

Hopefully that's it.

[Guest]

I don't think that matters one bit.

Its all related to how the analog signal is treated after it comes out of the PPU.

I think if you took a toploader and run the signal through the same path that the front loader has, it will come out clean with no lines. Its seems obvious that the frontloader and toploader have two different circuits for the composite video signal.

[leonk]

I've tried it, and failed.

I lifted pin 22 from a front loader (the video out pin) and ran a wire from pin 22 on the top loader to where pin 22 comes in on the front loader. I then powered both systems, and had a game inserted into the top loader.

The video coming out of the front loader was all messed up, probably because I needed to lift the pin on the top loader as well; the video signal coming out of the top loader was not strong enough to give video to both top and front loaders.

Does it make sense??

[DarthCloud]

hi,

I'm the one who made the little doc about the jio chip found in the new famicom.
I checked the path that the video circuit use in the NFC and draw this little circuit in paint Hope this help.

I will rewrite my doc with more info about the NFC instead of only pinout of JIO and corecting some typo . Will do that maybe this weekend.

Anyway there the pic: http://darthcloud.da.funpic.org/img/bypass.html

[drk421]

I looked at the schematics you provided.

They are definatly doing some filtering in after it gets to the tin metal box. There are some cap values that aren't specified in that schematic. I'm going to have a look in my NES later to see what they are.

I may be able to simply the circuit to just a few parts with a buffer (emitter follower).

[leonk]

DarthCloud: What's the voltage rating on C6 ?

Also, what is FC2?

[DarthCloud]

[DarthCloud]

**edit**

Excuse my previous answer I wronly understand your question lol

C6 is a normal ceramic cap, I don't realy have a way to know is voltage rating but it doesn't realy matter anyway for this one I think. Any 560pf cap should work. Give us news if you able to test these circuit in your redesign nes.

[Movax]

[drk421]

Well, its hard to tell what's going on in that metal can without breaking it apart. You can tell that schematic (orange one) was reverse engineered because it doesn't have values on some of the caps in the circuit.

I can only guesstimate them, and figure out what the key ingredient is to getting rid of the lines.

The official schematic posted is much too hard to read. It would greatly help me for an official schematic of what's in the little metal can.

[leonk]

SUCCESS!!!!

I'm not getting perfect, clean composite video out of my USA top loader!

Here's what I did:

- lift video out pin on top loader
- lift video out pin on front loader
- run a wire from video out on top loader to video out hole on front loader
- VERY IMPORTANT: connect the grounds between the 2 systems!
- power both systems

run game on top loader.. watch video from front loader. PERFECT CRIST VIDEO QUALITY!

So the problem is between the video out pin and output to TV. Time to redo that circuit.

[leonk]

more info update..

I build the small circuit board shown above (without the C6 or FC2) and the video quality is perfect!!!

This of course stops the RF from working, but who cares when the picture quality is PERFECT!

The only thing is the brightness is 1-2 levels lower. I think the extra cap and fuse cause the brightness to go up a notch.

What ever the case may be. It's all good now! I LOVE it!

UPDATE: I added FC2 and C6. Lots of them found on a front loader NES. It didn't do anything to the brightness. You should not be able to notice any brightness differencess unless you compare it to a front loader side by side.

What ever the case may be.. the video amp suggested above works. Now, time to try and get RF to function as well (but why bother!?)

[DarthCloud]

Cool leonk!!!

It's strange that the redesing nes was so ( ironicaly) badly desingned compared to NFC and even all other NES/FC/VS/PC system. Maybe NOA designed it instead of NCL ,who know. lol.