BVM 14G5U + SNES RGB sync issue

[mrmop520]

I'm having some trouble getting my SNES to sync and display the image properly on my BVM 14g5u. Just got cables from retrogamingcables (csync), and can't seem to get the image to stabilize at all. Oddly enough internal sync seems to be a clearer picture, while external is fast scrolling.

I was able to get a good picture through component with my Wii, so the monitor does work, but with rgb ->scart->bnc it's not giving me a steady picture at all. I'm still waiting on the 75 ohm terminators though, but I thought that only affected the picture quality (not having them makes it brighter).

Here are two pics, one with external selected, one with internal. Is it just the missing terminators or a menu option I missed?

[mrmop520]

For a little more context- component / composite is working great through the 27t card, while I tried using the original card + sync for the

RGB cables: (Super Nintendo Famicom SNES RGB SCART cable for NTSC console CSYNC- Output: EuroSCART- Sync : CSYNC (Composite sync), (Female RGBS SCART to BNC adapter cable for Sony PVM/ BVM monitors- Input type: EuroSCART)

Here's a pic of the back: (27t has 2 sets and original card has 1 rgb and sync)

[Sumez]

RGB cables: (Super Nintendo Famicom SNES RGB SCART cable for NTSC console CSYNC- Output: EuroSCART- Sync : CSYNC (Composite sync), (Female RGBS SCART to BNC adapter cable for Sony PVM/ BVM monitors- Input type: EuroSCART)

"Super Nintendo Famicom SNES RGB SCART"?
I'm not sure what this means, but if it's designed for a Super Famicom, could it possibly be a Japanese JP21 pinout, rather than European SCART?

Also, what's the output of your "SCART to BNC" adapter cable? The one I made has a BNC cable for the SCART cable's composite pin, which I plug into the "external sync" input on my PVM. This works fine for my SNES.

[mrmop520]

https://www.retrogamingcables.co.uk/nin ... -wire-cord

and

https://www.retrogamingcables.co.uk/son ... search=bnc

These are the 2 cables - the first one is for NTSC consoles, and I got it c-sync as my snes is a 1-chip-02

[Guspaz]

The BVMs don't have auto-termination, have you tried terminating the outputs (the sync at least)?

[mrmop520]

Yeah I messed around with the terminators, the monitor only came with 2 so i'm waiting on more in the mail now. I forget exactly what putting the terminator on the sync did - it definitely changed the picture but did not give a clearer picture at all. Think once I have 4 terminators it will fix the sync issue ? Also do I need terminators on all out ports or just the ones with inputs in use?

[Guspaz]

An unterminated image (seen on a BVM by not terminating the output, seen on a PVM by plugging an RCA adapter or disconnected cable into an output) should simply appear brighter. For the R/G/B channels, I don't think being unterminated would cause a problem (it would just be too bright), but for sync having a stronger than normal sync signal could cause it to fail to sync.

IIRC the 1chip have overly strong signals causing people to mod them to bring the levels down to normal, although I could be misremembering (did it only apply to the mini?) so perhaps your BVM doesn't like an overly strong sync signal from the 1chip? Have you tried a non-1chip SNES?

[mrmop520]

Yeah that's what I figured on the unterminated rgb signal, nope unfortunately I don't have another SNES to test it on.

[Fudoh]

Seems to be a cable issue. The sync signal just isn't getting through.

What you could try: set the monitor to internal sync, connect R+B as usual. Connect the sync line to the Y input instead and see what happens. This way you should be able to verify that the cable is working, although you don't get the right colors this way.

Another possiblity is that your 1CHIP doesn't have CSYNC connected. Nintendo changed this at some point and it doesn't neccessarily have to be the exact point where they switched from -02 to -03 models.

[mrmop520]

Ok ill give that a try tonight after work- if the signal comes through clearly does that means the cable
is functional just the sync isn't working? If that is the case a luma sync cable is the next step
to try?

[Guspaz]

Stable sync on screen when sync plug is connected to Y (green) input and monitor is set to INT sync: the cable is fine, the SNES csync output is fine, the monitor's sync input is bad

It's not really possible to tell the difference between the SNES not outputting csync and the cable being bad, because in either case there's not going to be any signal coming out the sync plug.

You can test if the SNES's luma sync is working by using s-video cables, since what a SNES sync-on-luma cable is using for sync is actually the s-video luma signal.

[mrmop520]

Appreciate the info, still new to this stuff theres a lot to learn! Hopefully its not the monitor input gone bad, I guess if it is though then component cables would be ok for the snes,they work fine for the wii.

[Fudoh]

Hopefully its not the monitor input gone bad

I doubt it and if that's really the case, you could still use a sync converter to get RGsB from RGBs sources.

My first guess would be that the adapter cable is possibly misconfigured. I've seen cables from retrogamingcables before that were wired for the wrong direction.

[mrmop520]

Ok, I tested the hookup with the sync on green, still not a stable image.

[Fudoh]

Maybe check the wiring of the adapter cable next. Make sure to check it's direction.

[mrmop520]

Hmm do I have to take apart the cable to do that? If that's the case I'll probably just check with the seller, maybe the csync for the 1chip02 isn't working and I need a luma sync?

[Fudoh]

just unscrew the scart header and check to which pin the sync line is connected. Done in 20 seconds.

[Sumez]

Does the composite video signal work on its own?

[mrmop520]

Ok didn't realize it was so easy, took it apart - it looked like the yellow was on the 20 pin (furthest one on the diagonal side). I think these pics show it.

[mrmop520]

Does the composite video signal work on its own?

You mean the sync cable as a composite source? Tried it and no picture at all.

[mrmop520]

Well the terminators arrived.. PS2 / wii look great over component! Didn't affect the SNES RGB issues though as suspected.

[haightc]

Well I would suspect you cables, the place where you ordered is know for quality cables but it looks like you got a bad one. Any I make my cables as the one I have purchased vary quality and it's you usually get a better/cheaper product if you just make it yourself. I think I had the same issue with the cable I originally bought for my SNES. I ended up just using the multi-out plug and making my own cable that worked much better!