@Classicgamer, Please don't take it personally, but I just think it's important to explain a few things about that Vogatek/arcade in general, so that misinformation isn't spread elsewhere, too.
Classicgamer wrote:
The thing that everyone thinking about buying one should be aware of is that they don't include the resistor array needed to display arcade RGB on a consumer rgb tv (or monitor). This is a serious flaw as their key purpose is to display arcade PCBs on a crt tv with rgb scart...
I've seen that supergun before, and it
does have resistors on the RGB lines and the CSync line, meaning that it is capable of bringing the signal amplitude to acceptable levels (below 1Vp-p). Sure, it doesn't buffer and impedance match the signals, but the signal amplitude is safe.
Classicgamer wrote:
If I try and use it on my broadcast monitor, the image is overly bright and can not be adjusted down to acceptable levels. Take note BVM / PVM owners. I believe this is why some people have had issues with consumer devices like upscalers not designed to handle a 5v rgb signal.
When I connect it to my arcade monitor and flick the 75ohm switch, the image comes out as it should in terms of brightness. But it has trouble with V hold, strange as I have no v hold issues with other sources and the Ikegami managed v hold just fine...
It was overly bright on the broadcast monitor and fine on the Ikegami with the 75R termination turned on - this basically means that your broadcast monitor lacked that termination (some monitors require external 75R termination caps).
Classicgamer wrote:
there is also other screen issues with geometry and shape on my arcade monitor that are not there on other sources. This tells me that the signal strength is too much even for a monitor design to handle arcade boards directly. The issues are similar to what I see when contrast is set too high and the coils overheat.
This has to do with the exact game you ran and your monitor, not the supergun. Arcade PCBs can output the CSync at 3-5Vp-p (TTL level), so there's no way the signal strength is too much for the arcade monitor.
Classicgamer wrote:
It won't display any image through my Extron interface which tells me that the sync signal is not clean. I suggest buying the more expensive scart to BNC adapters with built in sync strike and running the signal through a resistor array before plugging into any consumer display or scaler.
Arcade PCBs output perfect TTL Csync, so Sync Strike is not necessary at all. Maybe to act as a buffer (but there are better ways for digital signals), but not as something that can "fix" your sync from the arcade PCBs.
Classicgamer wrote:
The issue when using this Supergun on my arcade monitor was vertical hold problems. As the Supergun works fine on my Ikegami, I concluded that this is most likely caused by the sync on composite video. I have ordered another scart to BNC adapter but this time, I got the one with a built in sync stripper. I think that will solve any remaining issues.
Again, the arcade PCBs output Composite Sync, not Composite Video, so there's no point in stripping anything.
Classicgamer wrote:
It turns out that the excessive brightness when displayed on consumer level rgb monitors (BVMs, PVMs, Ikegami and rgb scart TVs etc) was caused by the power supply. These cheap eBay Superguns use regular PC ATX PSUs which is great for convenience and cost but.... cheap Superguns can be very sensitive to excess voltage or shortfalls.
A PC might work fine on 4.7v from the 5v line but not arcade PCBs so check you psu before use. After switching out my cheap Chinese PSU for a reliable one, I was able to display a nice image on my Ikegami monitor at correct brightness levels.
While I agree that +4.7V is a bit low, it has nothing to do with the supergun outputting overly bright picture. Furthermore, that supergun doesn't have any video signal buffers, just a bunch of resistors, so the supergun itself cannot be affected by under/overvoltage at all - it will be the actual PCB game.
I cannot explain why it started to output "normal" picture when you changed the PSU, but I'd start looking for the root cause in your specific setup (TV/monitor setting, video cables etc.). Hope that helps.