MiSTer FPGA Forum

I have my Mister running via the Analog Io RGB into a consumer RGB Scart Toshiba CRT and I’m experiencing very faint red scanning lines coming through on blacks . I’ve tried 2 cables , the later being the one from RGC , both have a resistor .

Brightness and contrast are set on the TV to acceptable levels and lowering either the contrast or brightness doesn’t seem to completely eliminate them . My CRT has a brightness range of 1-100 I think and I’m set to only 5 , any higher than that and the picture is too bright , to be honest even at 5 or even set to zero it would appear a bit too bright .

It’s a 37” CRT so I don’t know if that’s just part of the parcel and everything does become that more noticeable .

If I run the SNES 240p suite PLUGE my CRT seem so bright that I can’t really eliminate those side bars completely using the brightness and contrast settings of the TV . Therefore whatever they are in that test that are supposed to be eliminated with the TV brightness / contrast controls remain .

Running the Saturn itself via RGB scart doesn’t present and issue , just seems to be with the MIster

I was looking to try a VGA2SCART in the hope it would fix the anomalie .

Pics attached of what appear to be faint scanning lines coming though and the cheaper of the cables I’m using , the RGC one I’ve not opened . The cable shown is the one from RetroComputerShack .

Mister ini settings are correct , VGA_PWR on the IO is set to 5v as per the instruction of RGC when it comes to using their cable .

I’ve adjusted RCUT in the CRT service menu but it made no difference , I could mess with SUB Brightness in the service menu but don’t really want to get involved with that .

Io board is from Nat at https://misterfpga.co.uk so I don’t think it’s an issue with the IO board

Any thoughts ? Thanks in advance

Some CRT sets are sensitive to MiSTer's output resulting in anomalies. Things to try I can think of:
-check again your ini is really the latest one here: https://github.com/MiSTer-devel/Main_Mi ... MiSTer.ini
-try without the VGA_PWR jumper
-get one of the decent Direct Video dongles and see what happens

Im using the latest one with all options set to 0 other than composite sync which is set to 1 . VGA mode is set to rgb

what is the behaviour of setting vga to neutral , 3.3 or the 5v

you can see red in certain areas that are supposed to be black , pics from the wonderboy arcade core . one of the cores it doesn’t seem to happen on is the legend of tonma

wonderboy core

What is the source of the analog board? Can you take a picture of the resistor arrays near the vga connector?

I’m assuming the resister is on the pin shown above on the scart connector that’s heatshrinked ?

It’s as if something is coming in too hot . The brightness is too high really , the areas of concern I’m assuming are the areas you’re supposed to level out ( outer bars ) on the 240p test suite . I can’t level them out because the brightness is too high . As stated my brightness is set to only 5 in a range of 0-100 so I can’t take it down any more really . Lowering the brightness would I think solve the issue but I’d have to do it via the service menu … and then I’d have to put it back for every other console I use so that solution isn’t really feasible .

changing vga_pwr jumper back to just to the centre pin ( neutral) gives a picture but you can hardly see it .

the resistor is stated as being a 470 as with most of the cables

balladof32 wrote: ↑Mon Feb 05, 2024 5:51 pm

I’m assuming the resister is on the pin shown above on the scart connector that’s heatshrinked ?

No, on the analog board. Also, please answer where you got that board from.

the IO is from Nat at https://misterfpga.co.uk as per above . I’ll check the resistor now

Ah, sorry, I did not see it in the first post. Mine is from the same store, and I agree they do high quality work.

The reason I was asking about the resistor arrays is that they are responsible for creating the different analog signal strengths.

Io resistors …

similar issue ?

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