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Getting a better sync

TheBortot

TheBortot

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Just saw some comments about using a LM1881N sync stripper to make a better sync with arcade games or just consoles, but i have a doubt considering arcade pcbs:

Arcade pcbs outputs csync and then the conversion makes it to Hsync and Vsync. But my converted tv to RGB just have 1 entrance for sync(i mean, the yellow RCA one). How can i make a cleaner image? i got some white jailbars in some games and maybe this solve the problem.


Scheme that i`ve found:

https://ibb.co/eW9ctK
 
so your goal is to obtain a cleaner sync, right? I know some pcbs apexuallt bootlegs have terrible sync that .akea it hard to play it properly on a cabinet...
 
separating H from V sync really makes a difference?

Besides, i figured out that sync is not the problem with one of the pcbs i have - mortal kombat 2.
I`m getting some lines:
https://ibb.co/ngkkHe
 
I get those lines in my cabinet when the Bright is TOO high.

Notice that they are not completely horizontal, but they go slightly downwards from left to right.
 
this looks like the lines you get when the high voltage flyback transformer screen pot set too high, do this happen on every pcb of this tv set ?
 
Last edited:
tried to see if it was a flyback issue, but nothing...
 
You should get an Extron RGB interface. They sell for $15 on eBay and they solve a lot of issues.

They will clean up your sync signal and they can convert any type of sync to any type of sync. I.e they can convert RGBS to RGBHV or RGsB, or convert RGsB to RGBS (to use old consoles on an arcade monitor etc) or RGBHV. Or, convert any of those to RsGsBs.

They also have pots (or buttons) to move the image which is handy for monitors that don't have a remote board. And.... they give you a display to confirm that you have a 15khz signal before turning on an arcade monitor with a mame pcm or to confirm that Groovy mame is outputting the same refresh rate as the original PCB.

Basically, anyone who uses any type of rgb monitor should get one. Extron make some really nice kit. One of their interfaces will do a much better job than any of those cheap sync seperator circuit boards.
 
Zebra said:
You should get an Extron RGB interface. They sell for $15 on eBay and they solve a lot of issues.

They will clean up your sync signal and they can convert any type of sync to any type of sync. I.e they can convert RGBS to RGBHV or RGsB, or convert RGsB to RGBS (to use old consoles on an arcade monitor etc) or RGBHV. Or, convert any of those to RsGsBs.

They also have pots (or buttons) to move the image which is handy for monitors that don't have a remote board. And.... they give you a display to confirm that you have a 15khz signal before turning on an arcade monitor with a mame pcm or to confirm that Groovy mame is outputting the same refresh rate as the original PCB.

Basically, anyone who uses any type of rgb monitor should get one. Extron make some really nice kit. One of their interfaces will do a much better job than any of those cheap sync seperator circuit boards.
Click to expand...
It depends what version and model of Extron RGB you are using. Recentily i bought a Extron 202 RXi and had some problems.
1. It came with a problem Overload P/S on LCD screen, so i figured out that was the PSU, changed some caps and was alive again.
2. Some units have a problem with distortion on top of screen and no one knows how solve it without add one more extron RGB on the chain or turn on DDSP, but you'll lose the V and H shift. Problem was with PS2, GC, Taito F3, some MVS NEOGEO (there's few PCB with same model that din't have the problem).

I got some noise too, like a little horizontal interferance that can't be solved too, so i'll try get another unit.
 

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In my experience, if issues persist even when using an Extron interface, the problem is more serious than a dirty sync signal.


With my Extron interface I can feed it a horrible signal from one of my diy poorly grounded rgb cables without any shielding and still get the clearest image possible.

I use it with my PS2, PC with Groovymame and my Neo Geo MVS / supergun. My two main monitors are a tri-sync crt arcade monitor (that can take a 1v or 5v rgb signal) and an Ikegami TM20-90r broadcast monitor. I get a perfect image on both with all three machines.

Issues like distortion at the edge is more of a crt related issue and can not be solved by cleaning up the signal. I am no expert on interference but with my stuff, that kind of thing is usually solved with proposer emi shielding and making sure all magnetic sources are moved away from the screen.

My Ikegami monitor is fully shielded but my arcade monitors do not like being near my LCD screens or speakers etc.

It wouldn't hurt to try using the monitor in another room, testing sources with other monitors and testing other sources so you can narrow down where the actual issue is. Once you start getting into dry solder joints and looking for shorts, I have to refer to others.

With machines like a PS2, you can get high or low voltage issues by using the wrong RGB cable. If I remember correctly, a PS1 RGB cable had different resistors to a PS2 rgb cable. Arcade PCBs put out a 5v rgb signal so, to use one on a consumer tv or monitor, some type of step down is needed (like they have on superguns). Conversely, consumer consoles often look very dim on CGA arcade monitors made for a 5v signal. Ultimarc sells a signal booster for this purpose (pc on crt cga display).
 
Zebra said:
In my experience, if issues persist even when using an Extron interface, the problem is more serious than a dirty sync signal.


With my Extron interface I can feed it a horrible signal from one of my diy poorly grounded rgb cables without any shielding and still get the clearest image possible.

I use it with my PS2, PC with Groovymame and my Neo Geo MVS / supergun. My two main monitors are a tri-sync crt arcade monitor (that can take a 1v or 5v rgb signal) and an Ikegami TM20-90r broadcast monitor. I get a perfect image on both with all three machines.

Issues like distortion at the edge is more of a crt related issue and can not be solved by cleaning up the signal. I am no expert on interference but with my stuff, that kind of thing is usually solved with proposer emi shielding and making sure all magnetic sources are moved away from the screen.

My Ikegami monitor is fully shielded but my arcade monitors do not like being near my LCD screens or speakers etc.

It wouldn't hurt to try using the monitor in another room, testing sources with other monitors and testing other sources so you can narrow down where the actual issue is. Once you start getting into dry solder joints and looking for shorts, I have to refer to others.

With machines like a PS2, you can get high or low voltage issues by using the wrong RGB cable. If I remember correctly, a PS1 RGB cable had different resistors to a PS2 rgb cable. Arcade PCBs put out a 5v rgb signal so, to use one on a consumer tv or monitor, some type of step down is needed (like they have on superguns). Conversely, consumer consoles often look very dim on CGA arcade monitors made for a 5v signal. Ultimarc sells a signal booster for this purpose (pc on crt cga display).
Click to expand...
I don't use professional monitor, but SONY CRT consumers, one projection 53" and a 38" tube, so it's a little hard to try change the room haha
Btw, if i remove EXTRON from chain, the image is really clean. I'm using shielded cables and a decoder based on BA7230 (RGB to component).
 
Raph_friend said:
Zebra said:
In my experience, if issues persist even when using an Extron interface, the problem is more serious than a dirty sync signal.


With my Extron interface I can feed it a horrible signal from one of my diy poorly grounded rgb cables without any shielding and still get the clearest image possible.

I use it with my PS2, PC with Groovymame and my Neo Geo MVS / supergun. My two main monitors are a tri-sync crt arcade monitor (that can take a 1v or 5v rgb signal) and an Ikegami TM20-90r broadcast monitor. I get a perfect image on both with all three machines.

Issues like distortion at the edge is more of a crt related issue and can not be solved by cleaning up the signal. I am no expert on interference but with my stuff, that kind of thing is usually solved with proposer emi shielding and making sure all magnetic sources are moved away from the screen.

My Ikegami monitor is fully shielded but my arcade monitors do not like being near my LCD screens or speakers etc.

It wouldn't hurt to try using the monitor in another room, testing sources with other monitors and testing other sources so you can narrow down where the actual issue is. Once you start getting into dry solder joints and looking for shorts, I have to refer to others.

With machines like a PS2, you can get high or low voltage issues by using the wrong RGB cable. If I remember correctly, a PS1 RGB cable had different resistors to a PS2 rgb cable. Arcade PCBs put out a 5v rgb signal so, to use one on a consumer tv or monitor, some type of step down is needed (like they have on superguns). Conversely, consumer consoles often look very dim on CGA arcade monitors made for a 5v signal. Ultimarc sells a signal booster for this purpose (pc on crt cga display).
Click to expand...
I don't use professional monitor, but SONY CRT consumers, one projection 53" and a 38" tube, so it's a little hard to try change the room hahaBtw, if i remove EXTRON from chain, the image is really clean. I'm using shielded cables and a decoder based on BA7230 (RGB to component).


Sounds like your Extron is broken, or the dip switches are set wrong (inside or out).


I've used my Extron interface with Sony CRT TVs, pro monitors, arcade monitors. all without issue. It works with my Supergun, my PC and every game console too.


As they are so cheap, it's worth buying another to try once you have checked the internal and external dip switches.
Click to expand...
 
That's not broken, my friend, it's a known issue with some models. Everyone know that exist, but don't know how to fix.
 
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