Famicom av mod instructions?

[Hamburglar from MC Kids]

He is correct in that jailbars are a lot harder/impossible to see on a CRT. They only become very noticeable on a plasma/flatscreen or something without scanlines.

Right, but he using JUNK $5 device and upscaling to judge the mod. facepalm.jpg

If you understand WHY jailbars appearing, you can solve it. Have you ever had a real Hi-Fi audio system, not modern junk, real one. All grounding there made as star. This is the hint.

Not doubting you but if it is ground related, why are the jailbars way stronger when using a reproduction cart or PowerPak? Wouldn't that indicate it's an issue with power draw?

[famifan]

please don't care about my capture device.
It produces the same picture that i can see on my CRT TV but without horizontal lines, but the pic taken from the camera can't show the jailbars at all.

so pics are provided only for showing how it is difficult to shoot jailbars on the camera. Only strong jailbars become visible on camera's pics.

80sFREAK shows us only a few pics and claims that he have resolved the issue. But i can't reproduce the results he got (maybe because i don't have 14" CRT TV with the same color setting that he had). Maybe it is just me and someone else succeded with jailbars eliminating, i don't know. Who else is succeded?

[Da Bear]

Working on it when I have time!

Can also inform you that on my 14" CRT I can't see any jailbars with the mod I am doing. They are still there sadly enough, as I can see them very faint on my 50" plasma.

[famifan]

maybe i will redesign famicom PCB when i have enough free time. Dreaming about 2 copper layers on both PCB sides (for good ground and shielding)

[Hamburglar from MC Kids]

please don't care about my capture device.
It produces the same picture that i can see on my CRT TV but without horizontal lines, but the pic taken from the camera can't show the jailbars at all.

so pics are provided only for showing how it is difficult to shoot jailbars on the camera. Only strong jailbars become visible on camera's pics.

80sFREAK shows us only a few pics and claims that he have resolved the issue. But i can't reproduce the results he got (maybe because i don't have 14" CRT TV with the same color setting that he had). Maybe it is just me and someone else succeded with jailbars eliminating, i don't know. Who else is succeded?

I have been trying to get rid of jailbars for over a year, since they are very obvious on my plasma. The only thing that did it unfortunately is the XRGB Mini Framemeister. Using Mode1 or Game1 gets rid of jailbars somehow. I don't know what magic it does, but it somehow gets rid of them.

Anyone playing 240p game consoles (NES, SNES, Genesis, etc.) on an LCD or plasma owes it to themselves to pick an XRGB Mini up, though they are quite a bit expensive.

[HokusaiXL]

Necro-ing the thread I know. .  But out of curiosity, would it be possible to just replace the Famicom RF Modulator with one from the front load NES to get the desired AV out?

[jpx72]

Good thinking, but no. The main board of the NES is also responsible for the less "jail-barred" video signal. So yes, you can get AV out this way, but you will still get the jailbars (vertical lighter lines through screen).

[HokusaiXL]

Well with that being said, couldn't you harvest the parts from the NES board needed to clear the jail bars?  That and wouldn't the NES give you basically a drawn out map of how to assemble it?  Just rambling so if it's been mentioned don't mind me.

[jpx72]

Yes it has been mentioned, it's the way the traces are drawn on the PCB and the placement of the parts, not the parts themselves that matters here.

[HokusaiXL]

So more like weak traces and weak grounds on the famicom board?

[2A03]

Necro-ing the thread I know. .  But out of curiosity, would it be possible to just replace the Famicom RF Modulator with one from the front load NES to get the desired AV out?

I don't think there's enough room inside the Fami for the NES RF/AV box, plus you'd have to drill holes for the jacks and channel select switch. You're really much better off just doing an AV mod.

[famifan]

Tried to take photos, but pics looks far away from what i see in real. Are jailbars really bug or just feature to get extra color(google zx spectrum multicolor demo)?  For the first looks jailbars repeating at each 8th pixel, which makes sence - it's a bug on power line(and SMD capacitors and proper wiring changing picture quite a lot) or either shift register(it's inside PPU, so have to accept this as is). BUT, how to explain different pattern of "jailbars"? Keep in mind, that LCD TV's upscaling picture and algorithms can be different between different brands/models

http://www.famicomworld.com/forum/index.php?topic=4713.msg102415#msg102415

CHR A13

[famifan]

for quick test: just touch to CHR A13 PPU pin and to Video out pin by 2 your fingers simultaneously and look at what is going on the screen.



Post Merge: June 16, 2012, 09:02:44 am
i'm thinking about subtractioning CHR A13 signal from video signal by opamp. But it might  fail.
Post Merge: June 16, 2012, 12:23:44 pm

2)Lode Runner real IC's 4.90V on ROM chip - blue background absolutely clean with no jailbars
3)Mario Bros glop-top 4.95V on ROM chip - faint, but visible jailbars, white clouds are absolutely clear
4)Yoshi no tamago glob-top MMC1 4.95V on capacitor - jailbars on white screen, NO jailbars on blue screen. Also

LOL, what did you measure? 4.95 or 4.90? what equipment did you use?

4.95 - is okay for 7805 output, %2 tolerance. How did you get 4.90?

[famifan]

for quick test: just touch to CHR A13 PPU pin and to Video out pin by 2 your fingers simultaneously and look at what is going on the screen.



Post Merge: June 16, 2012, 09:02:44 am
i'm thinking about subtractioning CHR A13 signal from video signal by opamp. But it might  fail.
Post Merge: June 16, 2012, 12:23:44 pm

2)Lode Runner real IC's 4.90V on ROM chip - blue background absolutely clean with no jailbars
3)Mario Bros glop-top 4.95V on ROM chip - faint, but visible jailbars, white clouds are absolutely clear
4)Yoshi no tamago glob-top MMC1 4.95V on capacitor - jailbars on white screen, NO jailbars on blue screen. Also

LOL, what did you measure? 4.95 or 4.90? what equipment did you use?

4.95 - is okay for 7805 output, %2 tolerance. How did you get 4.90?

You know, boy, cooper on layout have resistance and Ohm was very clever guy. Should i continue?

As about CHR A13 - it gives 4 pixels wide stripes, not 1 pixel wide "jailbars".

Played around GPM-02 little bit. Rewiring CHR A13 gave amazing result... jailbars now on every odd pixel, but it can be result of upscaling

dear 80sFREAK, i don't want to hurt you, but to rely on your measurements you need the device with very high accurancy. If you used digital voltmeter/multimeter you've fucked up twice. Should i continue?

Not sure if you trying to troll me or just stupid. The simplest way to figure out that is just to suggest you to calculate how much is the copper layer resistance should be for reducing 5V to 4.9V. Could you calculate this?

already retraced CHR A13, and going to retrace tracks from #24, #23 ppu pins.

[famifan]

[
dear 80sFREAK, i don't want to hurt you, but to rely on your measurements you need the device with very high accurancy. If you used digital voltmeter/multimeter you've fucked up twice. Should i continue?

facepalm.jpg
Try to measure voltage in the different parts of your Famicom and with different cartriges. Result will surprize you

I wonder, if i get can get somewhere LCD screen without upscaling

well, i will try if i have the such high accurancy device. What is blocking you from answering some my question about your equipment? and how did you measure it.

e.g. if you use true 1% tolerance equipment and choose 0-10V gauge, your measurement accurancy step will be 10V*1% = 0.1V. In that case your device can't guerantee distinction between 4.90 and 4.95 even you've got it on the screen.  Should i continue feeding you?  

what is your device tolerance/accurancy?