AES and CMVS both look terrible on Sony BVM-20F1E Monitor

[brettster]

Hi all
I just got myself a Sony BVM-20F1E, Picture quality is awesome with a Super Nes or Megadrive
But Both my AES and CMVS look to be blurred / over exposed mess.

The Neo's are connected to the BVM by means of a BNC to RGB Scart adapter, this has a sync cleaner built in.

I have tried to add some 75ohm resistors to the RGB lines on the CMVS, also tried adding 220uf Caps and tried with both the caps and resistors but still the same.

Anyone come accross this issue before? the PQ was perfect on my old Hantarex Monitor / Samsung Plasma TV

Thanks

 

[Pasky]

Hi all
I just got myself a Sony BVM-20F1E, Picture quality is awesome with a Super Nes or Megadrive
But Both my AES and CMVS look to be blurred / over exposed mess.

The Neo's are connected to the BVM by means of a BNC to RGB Scart adapter, this has a sync cleaner built in.

I have tried to add some 75ohm resistors to the RGB lines on the CMVS, also tried adding 220uf Caps and tried with both the caps and resistors but still the same.

Anyone come accross this issue before? the PQ was perfect on my old Hantarex Monitor / Samsung Plasma TV

Thanks

Unsure with the way you worded your post. But if all you tried was 75 ohms, you'll need much larger resistors. In the 240Ohm range in series with the color lines.

http://www.neo-geo.com/forums/showthread.php?253360-MV-1C-RGB-Sync-Maximum-Vp-p-values

 

[Skips]

Unsure with the way you worded your post. But if all you tried was 75 ohms, you'll need much larger resistors. In the 240Ohm range in series with the color lines.

http://www.neo-geo.com/forums/showthread.php?253360-MV-1C-RGB-Sync-Maximum-Vp-p-values

Higher resistance wont do anything except blur it further on the BVM. You will need to put 75 ohm pull down resistors on each color line. To do this you can solder one end to the red pin then solder the other to the red ground pin. You will need to do this for each color. If there are no ground wires connected to the RGB ground pins you will need to connect each ground pin to pin 21. I had to do this when I had a BVM. On the CMVS it is because you are not clamping the RGB and are running it straight to the monitor. If 75 ohms ends up too bright you can drop the resistance to make it darker. A higher resistance will make the picture brighter.

 

[Pasky]

Higher resistance wont do anything except blur it further on the BVM. You will need to put 75 ohm pull down resistors on each color line. To do this you can solder one end to the red pin then solder the other to the red ground pin. You will need to do this for each color. If there are no ground wires connected to the RGB ground pins you will need to connect each ground pin to pin 21. I had to do this when I had a BVM. On the CMVS it is because you are not clamping the RGB and are running it straight to the monitor. If 75 ohms ends up too bright you can drop the resistance to make it darker. A higher resistance will make the picture brighter.

Is there no 75 -> ground inside the PVM/BVM's?

 

[Skips]

Is there no 75 -> ground inside the PVM/BVM's?

PVM's dont need to do this. I think the BVM has 75 ohm termination but i can not check since i dont have it anymore.

 

[Xian Xi]

The PVM iirc should have 75ohm termination. Are you using the same cable for both systems? If you are then that's the common thing between them and most likely the problem. Make sure you are getting ground from the CMVS/AES to the PVM. You might have mis-matching grounds and not connected in continuity between the devices.

 

[brettster]

Thanks for the Tips guys, Both Systems have their own cables, Termination on the BVM Cards may be the answer, both of the expansion cards in the BVM Monitor have BNC connections labelled in and out, I'll buy some 75 ohm bnc terminators and give that a go

 

[brettster]

Skips, You were Bang On with the RGB Clamp
I removed everything from the CMVS RGB lines in the Scart plug and added the 3 x 75Ohm resistors to each pin alongside the RGB wires and twisted the other ends of the Resistors together and joined them to Ground and the Picture quality is Amazing now. You have made my week

I'll see what the AES looks like unaltered when the 75Ohm BNC terminators arrive next week.

Thanks again for the help guys

 

[Skips]

Skips, You were Bang On with the RGB Clamp
I removed everything from the CMVS RGB lines in the Scart plug and added the 3 x 75Ohm resistors to each pin alongside the RGB wires and twisted the other ends of the Resistors together and joined them to Ground and the Picture quality is Amazing now. You have made my week

I'll see what the AES looks like unaltered when the 75Ohm BNC terminators arrive next week.

Thanks again for the help guys

Are you running the AES with an RGB bypass mod by any chance?

 

[MtothaJ]

I'll see what the AES looks like unaltered when the 75Ohm BNC terminators arrive next week.

Thanks again for the help guys

At least on my two BVM's no such terminators are needed, it will auto terminate if nothing is plugged into the OUT terminals.

 

[brettster]

Hi Skips yes the AES has the RGB bypass mod too as it had less than stellar performance. and audio swap too, perhaps the worst AES model there is

 

[K-2]

The 75 ohm BNC terminals are really necessary when you have synch tearing in the image. For example my Duo-r, (a system known for its finicky ways) was unplayable without plugging the outputs with the terminating caps.

I have a low number model AES which looks amazing on the 20F1. Same with my old AI CMVS.

 

[Skips]

Hi Skips yes the AES has the RGB bypass mod too as it had less than stellar performance. and audio swap too, perhaps the worst AES model there is

The 75 ohm resistors should fix it for the AES as well then, just wire them the same as you did with the CMVS.

 

[brettster]

Got the 75 Ohm Terminators today, Boom fixed the issues. just need to re adjust all my picture settings now

 

[Shozuki]

Got the 75 Ohm Terminators today, Boom fixed the issues. just need to re adjust all my picture settings now

Sorry to hijack. I just bought an AES cos my CMVS was having the same issues on my BVM!

Thing is all this 75 Ohm resistors is alien to me...

it's connected via RGB Scart what do I need to get it work exactly??

Thanks all!

 

[Xian Xi]

Sorry to hijack. I just bought an AES cos my CMVS was having the same issues on my BVM!

Thing is all this 75 Ohm resistors is alien to me...

it's connected via RGB Scart what do I need to get it work exactly??

Thanks all!

How are you connecting the SCART to the BVM? Make sure it's set to external sync.

 

[Shozuki]

How are you connecting the SCART to the BVM? Make sure it's set to external sync.

it is. Same issue with overly bright/saturated image...

 

[mikey]

It's just like Skips was saying, you need get 3 x 75ohm resisters and connect one end of a resister to each of the R, G, and B lines, and the other end of each resister then needs to connect to ground.

 

[Shozuki]

It's just like Skips was saying, you need get 3 x 75ohm resisters and connect one end of a resister to each of the R, G, and B lines, and the other end of each resister then needs to connect to ground.

Is that the case then? The thread creator mentioned he tried that initially and it didn't work...?

 

[mikey]

He initially tried them inline with the RGB signals, not terminated to ground. For a lot of video output signals, you require a 75ohm resister and 220uf cap inline with the signal. In this case you need the RGB lines terminated to ground with a 75 ohm resister.

 

[brettster]

the RGB Clamp using resistors way works or you can plug in the BNC terminators onto the outputs on the BVM Monitor I used 4 terminators one each for RGB and for sync too, this had the effect of a better centred screen.

 

[Shozuki]

Thanks again for the help all the resistors work a treat and the Neo looks incredible! Wow!!!!