Author Topic: MOD GUIDE - Universal RGB-to-YPbPr/Component Circuit & Mod [8/24/2014]  (Read 19588 times)

Game-Tech.US

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change R14 to 500ohms
add cap
I see two Q1's...
Are C1 and C2 22 'uF' or ?

thesteve

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so i got my Qs numbered wrong
yes 22uf c1, c2

NightWolve

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YPbPr (Plasma TV)
Composite (CRT TV)

EDIT: Whoops. Little bit of mis-communication there between steve and myself. I had suggested a RGB v. YPbPr compare, but these shots were YPbPr v. Composite... Results are self-evident. YPbPr is far superior of course!
« Last Edit: December 06, 2012, 12:15:31 AM by NightWolve »

ProfessorProfessorson

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I gather Steves set is suffering from some major lag there due to the difference in character animation taking place between the two tv sets. Lag looks to be significant too. But anyway, these shots with the phone camera are way too shity to make any good judgement calls on quality here. I'd rather stay reserved until work is finalized on the mod and someone with a decent camera can take some shots.

thesteve

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i wouldnt call that lag, as the plasma simply is showing 2 frames at once (displaying as 480I)

NightWolve

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I gather Steves set is suffering from some major lag there due to the difference in character animation taking place between the two tv sets. Lag looks to be significant too. But anyway, these shots with the phone camera are way too shity to make any good judgement calls on quality here. I'd rather stay reserved until work is finalized on the mod and someone with a decent camera can take some shots.

Eh, false alarm... Littl' bit of mis-communication with steve on this - figures, I bolded the question I was curious about (RGB v. YPbPr) but looks he mixed it with my suggestion to him about checking the Composite signal to make sure he's getting the color levels (and tint) right and what not.

steve, when I suggested a Composite comparison against the YPbPr output, that was meant for you, to help you make sure that the color levels just about match with the Composite output as well as the tint (on the same TV)! That's how I tweaked my SNES YPbPr mod: I would quickly switch from Composite, to S-Video and back to YPbPr output and try to get the color intensity to match just about. But yeah, I would suspect tint also might be an issue in your case. Kind of a no brainer, you probably already have been doing that, but it was just FYI.

As for the RGB v. YPbPr comparison, I wanted to get an idea of how much better analog RGB is compared to analog YPbPr in the case of a console, etc. I've corrected the labeling on the images above and of course they make sense now, seeing that YPbPr is far superior than Composite wasn't an unexpected result. I was more curious about how much better analog RGB is compared to YPbPr in this case. That's all. I was confused, I didn't think they differed by that much, but the shitty image was Composite all along... Anyway, carry on.

thesteve

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in my case RGB will be far superior, as my set supports 240P in RGB.
that difference wont be so noted on sets that do 240P component

ConHuevos

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Any updates on this?

thesteve

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i need someone to build from the schematic for verification

NightWolve

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Any updates on this?


Yeah, go ahead and build the schematic shown on the first post if you're feeling adventurous and wanna help the cause. ;) Steve and BlueBMV have a partnership to build pre-made PCBs eventually based on that schematic (with RGB and S-Video support also I believe) to make it easy for everyone (you'd mainly just have to solder wires to the Luma, RGB and Sync pins, Composite, +5V, Ground, etc. and then to the RCA/S-Video outputs), but steve wants some more verification by others to manually build what's there before taking that final step. It was implemented on 8bit4Life's (a customer of steve's) Turbo Duo so far with success.

i need someone to build from the schematic for verification


Sorry steve, I still gotta do a full capacitor replacement first on my Turbo Duo motherboard (I want it 100% restored before doing the mods along with plans for videos) and I just have been doing other things lately (SNES) along with other distractions and downtime, etc., so I don't wanna hold you up with your plans for manufacturing boards. I think the only tweak I could help you with is determining the best output resistance value for Luma instead of having to use a potentiometer, but maybe you like having a pot there better anyhow. I assume Blue was going to build it manually as well, no? Anyway, I'll see what happens; it's *ON* my To-Do list no doubt, it's just my energy levels, interest, enthusiasm, mood, etc. change over time. You know how it is.
« Last Edit: January 25, 2013, 08:33:36 PM by NightWolve »

Game-Tech.US

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you'd mainly just have to solder wires to the Luma, RGB and Sync pins, Composite, +5V, Ground, etc. and then to the RCA/S-Video outputs
I just tried this and got nothing, I did have a 3904 in backward at first and one jumper missing, but all I get is black screen.
I see no place for luma, composite, or +5v in to this circuit or svid out, did I miss some things or did you list the extra stuff for no reason? ;)
I assume sync is used for S input, but a few posts in NW is talking about how it uses Y(luma) another mistake on the schematic or what?
Can I also assume it's ok to pull rgb straight from the 6260?
Where do you pull sync (or luma)?
I'm trying this on a Duo.

NightWolve

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you'd mainly just have to solder wires to the Luma, RGB and Sync pins, Composite, +5V, Ground, etc. and then to the RCA/S-Video outputs ...
I see no place for luma, composite, or +5v in to this circuit or svid out, did I miss some things or did you list the extra stuff for no reason? ;) I assume sync is used for S input, but a few posts in NW is talking about how it uses Y(luma) another mistake on the schematic or what? Where do you pull sync (or luma)?


You misread that paragraph and confused that comment with the separate Component circuit in the schematic. I wouldn't list stuff for no reason... I simply mentioned future plans that steve/BMV have which is to manufacture and sell their own video boards (like JROK). Such a pre-made board would have it *all*, multiple video outputs: S-Video, RGB, and Component and all you'd have to do is solder the input end and the output end, etc. Such a board would use the natively produced Luma (pin 40) for the S-Video aspect, hence why I mentioned it. Why did I mention anything about it at all ?? To let people know a pretty cool idea is in the works, etc.

Quote
Can I also assume it's ok to pull rgb straight from the 6260?


Never done a RGB amp mod for a customer ?? I don't think you can tap them from anywhere else (never seen any mod where they weren't tapped from the pins of the chip) cause they're not actually used by the system elsewhere I read (The chip produces Y, R-Y, B-Y and CB to mix for a Composite amp and that leaves the chip). Well, here:

Yellow is for Sync, RGB pins are color matched. Exact:

pin 51 - Blue
pin 49 - Red
pin 47 - Green
pin 44 - Composite Sync

So, you got 4 signal inputs going into this Component circuit and +5V (plus ground) for you to decide wherever to tap. Steve didn't make his schematic very detailed, but the +5V goes into the power line the transistors are sharing. I just made a quick redo:



Quote
I just tried this and got nothing, I did have a 3904 in backward at first and one jumper missing, but all I get is black screen.


I would replace that transistor. Assume it's been damaged to avoid complications in building this.

Anyhow, good luck!
« Last Edit: March 19, 2013, 08:24:45 PM by NightWolve »

Game-Tech.US

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Never done a RGB amp mod for a customer ??
You may not believe it, but NO, never have actually gotten a customer to say yes lets do any video mod requiring rgb to start with, so far just adding composite and stereo jacks to the rear is as far as i've been asked to go, but I really want to sell what consoles I have with component outs.
So, you got 4 signal inputs going into this Component circuit and +5V (plus ground) for you to decide wherever to tap. Steve didn't make his schematic very detailed, but the +5V goes into the power line the transistors are sharing. I just made a quick redo:
Holy crap! Why would you show gnd but not +5V!?!? LOL
Glad I asked about it! I almost was sure there had to be +5V somewhere...
Anyway, thanks a bunch for clearing up some stuff for me, you've been super helpful.
I'll go back at it today/tonight and report back as soon as I know anything.

Game-Tech.US

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Here's some video of what i've got, it's way too dark and maybe too heavy on green.
Can you tell me what voltages I should see from signal to gnd on rgb in's, and Y, Pb, and Pr outs?
« Last Edit: January 03, 2014, 04:02:02 AM by akaviolence »

Bernie

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Ok, I have
, but it's way too dark and maybe too heavy on green.
Can you tell me what voltages I should see from signal to gnd on rgb in's, and Y, Pb, and Pr outs?



I cant tell you what is what, but I hope yall get this figured out.  :)