MOD GUIDE - Universal RGB-to-YPbPr/Component Circuit & Mod [8/24/2014]

[8bitForLife]

Hi long time no see I was the original ginny pig for this mod. Has there been any advances since mine was done should I send my turbo duo rx to someone my rca jacks arent green blue red which is an ocd thing for me also lol. I think it was all he had at the time.

Second question is it still possible to put rgb on my turbo duo rx I plan on getting a xrgb mini with tax returns.

[thesteve]

Yes RGB can still be done
The color has been improved a bit

Sent from my ADR6300 using Tapatalk 2

[thesteve]

improved compatability and 0V offset on Y

[NightWolve]

OP updated! Good man steve! So 470 uF DC filter cap on our Luma/Y line, check, and now 7 transistors even. I tweaked your schematic a bit right quick, squished it to fit without horizontal scrolling, added credits, etc. Some day I promise to make it all pretty like my unfinished SNES stuff to help make it more easier to read for the masses. Want it to look as pretty as say this:

[thesteve]

220Uf is considered ok, but 470UF is the standard
I also changed my luma input cap to 470UF as I wasn't happy will the Luma sag I was getting on my scope

[thesteve]

just corrected error on schematic

[turbokon]

I notice the 220uf at rgb inputs.  Is 22uf ok to use instead.

[thesteve]

Should work fine, just better white level, with bigger caps

[thesteve]

Please update first schematic again

[thesteve]

C1 C2 C3 are optional
may help with some systems, but not needed on PCE

[thesteve]

block diagram

[NightWolve]

So, I was updating this, saw you made quite a bit of changes, and then realized I don't understand the arrows to the two 10 KOhm resistors for mixing the -Y into Red and Blue that you did... What the heck is going on there ? Will have to simplify that as fewer people will understand that notation. Is it 5 K to the left, 5 K to the right, and the connecting point going to the base of the transistors ?

[turbokon]

So, I was updating this, saw you made quite a bit of changes, and then realized I don't understand the arrows to the two 10 KOhm resistors for mixing the -Y into Red and Blue that you did... What the heck is going on there ? Will have to simplify that as fewer people will understand that notation. Is it 5 K to the left, 5 K to the right, and the connecting point going to the base of the transistors ?

That's for the pots I believe.

[thesteve]

that is a standard notation for a 10K pot
it shows a resistor with unfixed center tap

[NightWolve]

Ah, I get it, so the 2 pins on one side of the 10K pot would connect to the left and right points (incoming signal + inverse Luma/Y and DC) and the single, center pin would connect to the transistor's base.

What is the default setting to initialize the pot with that's best ? Like 6.8K was the previous solid resistor choice.

Well, lemme know if you're fully done with the design, I might just work on making it look pretty soon.