Why does YPbPr look extremely blue? External RGBHV to Component looks fine? (pictures inside)

[sofakng]

I'm using an I/O board v6.1 and I'm trying to use YPbPr but the picture is extremely blue on my CRT TV.

I've purchased a VGA 15-pin to 3 RCA cable from Amazon and I've enabled [ypbpr=1] in the MiSTer.ini file. I also had to set the SOG switch to [ON], but this is the picture:

LtISON5m.jpg (10.06 KiB) Viewed 2524 times

However, if I disable YPbPr and use a standard VGA cable with my external RGBHV to Component transcoder the picture looks fine:

LGMnxbCm.jpg (11.46 KiB) Viewed 2524 times

What could be causing this? The VGA to 3-RCA cable has no resistors and is wired simply: 1 -> Red, 2 -> Green, 3 -> Blue.

[aberu]

(nvm just reread your comment again and noticed i missed that you already changed the mister.ini option, edited out that bit)

The jumper for the VGA port is it set to 3.3v or 5v or is it not set to either? I think sorgelig suggests by default that jumper to be clear if you are doing YPbPr, but can't remember completely.

To compare, i use one of these cables and everything works fine on my end: https://misteraddons.com/products/vga-t ... pbpr-cable

[ExCyber]

Maybe the Pb signal is shorted to ground in the cable? I don't have any specific experience with such a failure, but it seems plausible from some napkin algebra:

Code: Select all

 Pb = B - Y
 0  = B - Y
+Y       +Y
 Y  = B

[sofakng]

The jumper for the VGA port is it set to 3.3v or 5v or is it not set to either? I think sorgelig suggests by default that jumper to be clear if you are doing YPbPr, but can't remember completely.

The jumper isn't populated.

EDIT: The MisterAddons cable looks really nice and thick. The one from Amazon is pretty thin... MisterAddons looks like this Monoprice cable.

Maybe the Pb signal is shorted to ground in the cable? I don't have any specific experience with such a failure, but it seems plausible from some napkin algebra:

I just checked with my meter and blue (Pb) isn't shorted to ground.

[sofakng]

I figured out the problem. It was bad solder joints. It's working perfectly now and I'm really sorry for posting this, but hopefully if somebody else has the same problem they will know it's most likely solder-related.