RGB NES / Famicom and jailbar removal

Grambo wrote:

Skips wrote:

There are currently a few different groups/people that have managed to pull digital signals from the stock composite PPU through the use of FPGA. I am sure this type of mod will eventually be sold as a kit by someone in the future and does not require you to remove the composite PPU.

Right, I guess just from what I've seen out there, it seems to me that out of all the upcoming RGB solutions, the Universal PPU seems as though it has the most drive towards being a distributed, consumer product.

Getting digital signals from the original composite ppu is the best consumer product. You then take the digital signals and convert them into whatever video format you like, it can be rgb, hdmi, anything. The pallette can be any pallette you want including the original composite ppu pallette. You're using the original ppu so it will be fully compatible and have zero issues. The "universal ppu" project was started before people discovered that you can get digital video signals from the composite ppu using a trick.

With the universal ppu he ran into a bunch of different issues as to be expected with replacing the entire ppu. With this newer mod that uses the existing ppu there's already a bunch of fully functioning and issue free prototypes.

Im wondering if the fpga interpreter or the universal ppu will work in a playchoice so i can put some of these boards back together.

Drakon wrote:

Grambo wrote:

Skips wrote:

There are currently a few different groups/people that have managed to pull digital signals from the stock composite PPU through the use of FPGA. I am sure this type of mod will eventually be sold as a kit by someone in the future and does not require you to remove the composite PPU.

Right, I guess just from what I've seen out there, it seems to me that out of all the upcoming RGB solutions, the Universal PPU seems as though it has the most drive towards being a distributed, consumer product.

Getting digital signals from the original composite ppu is the best consumer product. You then take the digital signals and convert them into whatever video format you like, it can be rgb, hdmi, anything. The pallette can be any pallette you want including the original composite ppu pallette. You're using the original ppu so it will be fully compatible and have zero issues. The "universal ppu" project was started before people discovered that you can get digital video signals from the composite ppu using a trick.

With the universal ppu he ran into a bunch of different issues as to be expected with replacing the entire ppu. With this newer mod that uses the existing ppu there's already a bunch of fully functioning and issue free prototypes.

i dont glue things down until im finished with that part of the project. Meanwhile, they break from messing around with them i guess.

mvsfan wrote:

mvsfan wrote:

i ran the sync through the composite circuit and it worked perfectly for about an hour now the picture is rolling again.

wtf?

Got it. something is loose. if i push down on the pcb the sync comes back and works fine.

Btw, I fixed the blue today. I now have a correct picture.

im going to measure the sync pins on the 1881 and see if theres any resistance on them. Resistance = bad solder connection.

This is looking good. its almost time to play some games.

Btw, did you notice the wavy interference in those color pics i sent you? its not jailbars - looks more like power problem.

any ideas on how to fix that?

I also rewired the grounds in the scart socket to seperate video, chassis, and audio ground and the faint jailbars i was getting are now gone.

[quote="mvsfan"]


btw, skips thanks for the excellent tips.

Next time im going to try building it like you and drakon figured out to build it and see if its any better.

I am Very pleased with my results sofar though.

I thought that just by wiring this back up to an nes-cpu-11 i was going to have heavy jailbars, but thats just not the case. they are gone. my rewiring worked.

my original design was crappy i have learned a lot since i first wired this.

I don't know what wavy pictures you mean, post them here for us to see.

Drakon wrote:

I don't know what wavy pictures you mean, post them here for us to see.

i emailed them to you, drakon.

mvsfan wrote:

Drakon wrote:

I don't know what wavy pictures you mean, post them here for us to see.

i emailed them to you, drakon.

hey, do i have to have image hosting to post pics in the forum or can i just select them and upload to the forum like on gamesx?

I'm not sure, I use imgur to host my pictures and just stick them here from imgur links.

thanks. I just got a host.

Im not sure if you can make out the interference in these images but its there. its not jailbars though.

https://i.imgur.com/ZKYEDAn.jpg

[url=<a href="https://imgur.com/oCydRrF"><img src="https://i.imgur.com/oCydRrF.jpg" title="Hosted by imgur.com"/></a>]<a href="https://imgur.com/oCydRrF"><img src="https://i.imgur.com/oCydRrF.jpg" title="Hosted by imgur.com"/></a>[/url]

https://i.imgur.com/AG8wsQj.jpg
https://i.imgur.com/qeArfqY.jpg

This is a better image. It captures the interference in the side bars on the title screen you can see how its wavy.

https://i.imgur.com/D9eEmXM.jpg

Looks like a sync issue to me.

would having caps on the rgb lines clear that up?

ive already got a 220uf cap on the sync line. the store only had 1 of them though i wanted 4.

mvsfan wrote:

would having caps on the rgb lines clear that up?

ive already got a 220uf cap on the sync line. the store only had 1 of them though i wanted 4.

I did continuity tests on the 1881 chip legs to make sure they were soldered good, i re-wired one of the sync lines into one piece instead of several i had pieced together due to changes, and everything seems to check out as having good connections.
I also connected it through the composite circuit.

every once in a while the picture will slightly roll 1 or 2 times then stop, wich does lead me to agree that the interference could be a sync issue.

but ...whats the cure?

mvsfan wrote:

mvsfan wrote:

would having caps on the rgb lines clear that up?

ive already got a 220uf cap on the sync line. the store only had 1 of them though i wanted 4.

I did continuity tests on the 1881 chip legs to make sure they were soldered good, i re-wired one of the sync lines into one piece instead of several i had pieced together due to changes, and everything seems to check out as having good connections.
I also connected it through the composite circuit.

every once in a while the picture will slightly roll 1 or 2 times then stop, wich does lead me to agree that the interference could be a sync issue.

but ...whats the cure?

also, my capture card wont even touch this yet. just gives me no video.

Question: if there was something wrong with the power circuit going to the 1881, would i still get an image out of the output like i am, or does the 1881 need to be powered to allow the sync through?

btw, a big to you, drakon for getting rid of my bars. remember people, Distance from ppu to amp is critical - and so is proper grounding.

mvsfan wrote:

btw, a big to you, drakon for getting rid of my bars. remember people, Distance from ppu to amp is critical - and so is proper grounding.

Im going to try something else thats simple enough.

I still have the old through-hole 1881 board i built before.

theres a possibility that i damaged the new 1881 when i had the input and output swapped.

heres some more of my project. the last one, is more interference. also - the interference moves, it scrolls up and down.

those came out way too big im just going to stick with links to imgur like i was doing.

nevermind, i resized all of them to 640x480.

on that last image you can see the wavy lines on the yellow wall.

drakon - what do you think of the possibility that the lm1881 got damaged and isnt working right?