CMVS RGB Scart issue

[Ghudda]

So this is my first time hooking up my CMVS after receiving my scart cable from retro_console_accessories on eBay (http://www.ebay.com/itm/161253121219) and it seems as though i'm having an issue with the sync. I'm using the standard Euro BNC > Scart adapter with the cable and use RGB Scart with many of my other consoles but am having problems with this one. It's probably just something to do with the cable and not being wired for sync properly?

I'm unsure of how the CMVS is wired up inside (composite sync, etc)
Forgive me for the lack of RGB technical knowledge!

W/O EXT Sync


W/ EXT Sync


Thanks

 

[skate323k137]

Most likely you actually should have the EXT SYNC on on the monitor itself. It's probably going to come down to how the cable is wired, and/or if there's anything in your CMVS that may be wired incorrectly.

Is that a PVM 20M4U?

 

[Atro]

Could you check the value of the resistor on the sync line?

A picture of the wiring may help too.

 

[skate323k137]

Picture(s) of the CMVS, as well as the inside of the cable at the SCART connector, would both help.

When I use my MVS on a PVM, i have 220 ohms of resistance on R G B and on Sync too.

 

[Skips]

If external sync is turned on chances are your CMVS is using composite video for sync. A good deal of PVM's (especially the later ones) tend to be picky with composite video as sync depending on the game console. What type of PVM is that and is your CMVS something like an Omega or AI or home built?

 

[Ghudda]

If external sync is turned on chances are your CMVS is using composite video for sync. A good deal of PVM's (especially the later ones) tend to be picky with composite video as sync depending on the game console. What type of PVM is that and is your CMVS something like an Omega or AI or home built?

I have the option to either enable or disable EXT sync. The image seems to be best when EXT. Sync is disabled, though.
PVM Model is 20M4U
The CMVS is one of Xian Xi's customs (not original owner).

Picture(s) of the CMVS, as well as the inside of the cable at the SCART connector, would both help.

When I use my MVS on a PVM, i have 220 ohms of resistance on R G B and on Sync too.

I had this issue with my SNES mini that I had RGB modded. The modder didn't include wiring for the composite sync and so I had to modify the SCART cable to include it itself (that cable was from http://www.retrogamingcables.com/ and included a yellow sync wire that wasnt attached to a pin in the cable and I just had to connect that wire to the right pin).
Let me know of anything else you need photo or detail wise. Would the sync resistor be in the CMVS or on the cable? I do have a multimeter so I would be able to check it.
Photos of SCART cable:

 

[skate323k137]

20M4U (at least mine) has no problem with cvid as sync, however, a CMVS is only going to output sync not composite video unless there's an encoder installed.

You probably need to trace the positive of the sync BNC back to the proper pin on the scart socket (on your scart > BNC breakout cable), then check the corresponding pin on the cable you bought to make sure sync is wired to there.

BTW, It may look "better" with ext sync disabled, but in order to be correct, it needs proper sync on EXT SYNC in, with EXT SYNC on.

If you're in doubt Just hit up Xian Xi and see how he wired it on the MVS end. This will save a lot of guess work.

 

[Ghudda]

20M4U (at least mine) has no problem with cvid as sync, however, a CMVS is only going to output sync not composite video unless there's an encoder installed.

You probably need to trace the positive of the sync BNC back to the proper pin on the scart socket (on your scart > BNC breakout cable), then check the corresponding pin on the cable you bought to make sure sync is wired to there.

BTW, It may look "better" with ext sync disabled, but in order to be correct, it needs proper sync on EXT SYNC in, with EXT SYNC on.

If you're in doubt Just hit up Xian Xi and see how he wired it on the MVS end. This will save a lot of guess work.

Thanks buddy, i'll shoot Xian a message and see what he says about the MVS wiring.

 

[Atro]

I see no resistors at all on the SCART connector end.

They might be in side the CMVS perhaps.
I once forgot to put a resistor on a sync line of a supergun and got the same issue as you.
I placed the resistor and the problem was gone.

However, I wasn't dealing with a PVM.

 

[Ghudda]

I see no resistors at all on the SCART connector end.

They might be in side the CMVS perhaps.
I once forgot to put a resistor on a sync line of a supergun and got the same issue as you.
I placed the resistor and the problem was gone.

However, I wasn't dealing with a PVM.

This could be a possibility. The SCART cable for my SNES has resistors on it where as this one does not. The problem is that there isnt a standard for dealing with the sync so it's hard to account for it when buying a cable. I may pop the lid off the CMVS in a bit and check it myself but i'm not sure how crazy the wiring is under the hood. I did message Xian Xi so he should be able to give me an idea of the wiring layout.

 

[Xian Xi]

It's probably a version that has sync on pin 3 and audio right on pin 7. I standardized my pinout somewhere down the line to Sync on 3 and Audio R on 7, some older models have sync on 7 if audio is via RCA or headphone jacks.

 

[Ghudda]

It's probably a version that has sync on pin 3 and audio right on pin 7. I standardized my pinout somewhere down the line to Sync on 3 and Audio R on 7, some older models have sync on 7 if audio is via RCA or headphone jacks.

Yeah this one doesn't seem to pass audio through the scart. In other words, I'm not getting an audio from the scart cable. There is an aux port on the back near the RGB out. Does this mean that I need to account for it in the RGB scart cable I bought and switch the wires around?

EDIT: This is the exact pin layout on the scart cable.
So I would just move the wire from pin 20 over to pin 3?

 

[Xian Xi]

If you send me the console I can wire it whatever way you want. All my units are custom made so sometimes people ask for certain pinouts for cables they already have.

If there is no audio then sync will be on pin 7, so you need to open the cable you bought on the opposite side and move the wire on pin 3 to pin 7. If you want to add audio, I can add it in or if you want to do it yourself you can do it two ways, either open the console up and wire it in to the socket or you can use a headphone jack and run it in the cable to the respective pins to the scart connector.

 

[Ghudda]

If you send me the console I can wire it whatever way you want. All my units are custom made so sometimes people ask for certain pinouts for cables they already have.

If there is no audio then sync will be on pin 7, so you need to open the cable you bought on the opposite side and move the wire on pin 3 to pin 7. If you want to add audio, I can add it in or if you want to do it yourself you can do it two ways, either open the console up and wire it in to the socket or you can use a headphone jack and run it in the cable to the respective pins to the scart connector.

Agh, so it has to be done on the DIN8 side and not the scart side?
I may end up needing to send you the console then and having it wired up to the specifications of the cable.

 

[Ghudda]

Xian it looks like your inbox is full. Shoot me a PM when you get a chance and we'll work out getting this on it's way out to you.

 

[Ghudda]

CMVS is on it's way to Xian! Thanks for the help, everyone.

 

[NEO G-TRON]

I'm experiencing the same problem with my Aes doing the same thing but only on my PVM-2950Q .. My Aes including my other RGB ready consoles display perfectly fine on any of my 20" inch PVM's .. I was told that maybe I need to add a sync stripper to my female Scart to BNC cable. Dose that sound about right ??

 

[skate323k137]

Yes, you most likely need a sync stripper for that particular PVM.

 

[Xian Xi]

I'm experiencing the same problem with my Aes doing the same thing but only on my PVM-2950Q .. My Aes including my other RGB ready consoles display perfectly fine on any of my 20" inch PVM's .. I was told that maybe I need to add a sync stripper to my female Scart to BNC cable. Dose that sound about right ??

Like said, you most likely need a sync stripper since the your AES most likely has composite video on both pins 3 and 7 and the PVM won't like that.