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

[crans]

Just checking in noticed I put 1uf not .1uf as I should have.

[Xenogears]

Hello guys, back from sickbay this Weekend I will again encounter the "Shift-screen-Battle". Thesteve - your last Idea fits perfect to the issue. I used the Testsuit 240p and found out, that the Image is in deed double layered, shifted to right and not only bleeding. Update will follow...

UPDATE - PROBLEM SOLVED but still weired -

It was missing Ground ! Inside the 8-Pin-Din-Input, there is a small Ground-Connection getting into contact with the Shield-round Metal Part of the DIN-Plug. If the Ground-Connection is missing, you get the Problem. Weired: even if you connect GND and Shild inside the cable, the issue will still come up. You have to install the Ground Connection!!!

[Keith Courage]

I am trying to install one of these in a TG16 docking station for the first time. I've installed this board in many DUOs and TG16 systems without any issues.

Anyways, I am having trouble finding a good ground. I've even tapped the ground from the expansion port and it doesn't help. The problem I am having is the picture will not stay steady no matter how I adjust the brightness gain pot. I had the same issue in a DUO in the past before I found a good ground.

Anyone have any suggestions?

[Keith Courage]

Found the issue. Thought I'd post in case anyone else ever has this issue. Not sure how or why but the ground from the expansion port on the TG was not getting the same ground provided from the Hu6260 chip. I simply tapped a wire from the chip to the expansion ground and problem solved. First time I've encountered that.

[poponon]

This is amazing and I can't wait to get building one. Question though - would it be possible to make this into a standalone universal rgb to yuv transcoder if you source the 5v input from an AC adapter ?

[NightWolve]

Sure, it is pretty universal. Here's essentially a fan-made turbo booster using this circuit:

https://www.pcenginefx.com/forums/index.php?topic=14876.msg392378#msg392378

It started with TG-16, but he added the SNES Multi-AV cable for units that had RGB available all along.

[poponon]

that's awesome and more along the lines of what I'm thinking

In particular I'm thinking if I could hook up the circuit to a female SCART input so I could use it for multiple consoles and maybe a 15khz mamebox in the future. SCART in particular so I could still use the consoles with my upscaler when on flatscreens. I was hoping I could build something sort of like the csy2100 or the tc1600 transcoders. Just thought it'd be a fun project especially considering the tc1600 isn't being produced anymore (the developer passed away). And the screens people are posting look pretty mint

[thesteve]

thats exactly how i had it set up when i was building this circuit
was swapping between PCE and GENI scart cables

[poponon]

did you attach both SCART pins 8 and 16 to the circuit 5v input? or just one

sorry if the question is really basic, I'm basing it off these:

[thesteve]

Just 8

[poponon]

awesome, just ordered all the remaining parts. I'll post some pics of the end product once completed

[lastcallhall]

So, I have a question... I bought a few of these chips from Turbokon, and I set to installing 2 of them into a Genesis and a Master System. On both systems, with two different chips, my colors are coming out very dark. The whites look like a medium grey and the remaining colors are dark, as well. I tried tweaking the luma signal but that only served to make the colors look washed out, and not brighter. So, I removed the 1k resistors that are connected to the RGB inputs and replaced them with 1.5k resistors. no change. I'm tapping into a CXA1145 encoder on both systems. I haven't tried it with my SNES yet, but I wanted to get this resolved before I move on.

Here's a question: For sync, I'm tapping into the sync pin and not the composite pin. Would that make a difference? I'm using the older encoders for this, so I thought without the LM1881 I could use the sync signal without issue (I'm using sync out, not sync in). I'd really appreciate any help on this. Thanks!

Edit, I have also tried this circuit on a Genesis:



This circuit works fine, and on the same television, the colors look correct. I could build this circuit, but since I have the chips from TK, I want to use those instead. Thanks.

[thesteve]

what version of the board do you have?
the original board works well with 1K input resistors and no caps
the sync must be C-Sync when it gets to the circuit (LM1881 or any other TTL sync source is fine
the new board needs the 75ohm resistors installed on the board and 75ohm resistors with caps between the CXA and the inputs (as found in the GENI SCART cable)

[lastcallhall]

Hey Thesteve, thanks for writing me back.

To answer your questions:

It is the old version of the board. I bought about 15 of them a few weeks back.

I have placed 1K and 1.5K resistors on the board, both to the inputs themselves, as well as to the input solder points of the resistors (which had been suggested by Turbokon). The video is still dark either way.

I've tapped C-sync from the AV out as well as directly from pin 11 of the CXA1145 - there is no change in quality.

I'm in the process of building the circuit I already posted to show off the difference.

Thanks again!

[thesteve]

well never had a dark pic issue.....that i can think of