Messing with GBS-8220 video converter

[SignOfGoob]

One of these came in the mail today:

For those that don't know, you can get them here:

http://www.jammaboards.com/store/cga/ega/yuv-to-vga-converter-pcb-gbs-8220/prod_291.html

I tried it out on a few things. Everything looked bad on the Viewsonic LCD because I can't figure out how to make it not scale, but when I switched to an old Dell 17" CRT things got really good.

It runs with PS2 and GC through component pretty damn good, aside from all the fake low-res issues 2D games for those systems have.

I tried feeding it unmodified Genesis 1 and PC Engine RGB signals...neither worked very well. The PC Engine synched a lot better than the Genesis, but neither really worked. I've got parts for a PCE RGP amp coming in the mail that I hope will help with this issue. I also found details of how to get a better Genesis RGB signal with resisters and caps. I'll try that too.

I hooked my 2 slot up to it and had no issues. In fact, that flicker in Pulstar when it switches between game play and anything else? Even that's gone. The visual experience isn't much different from Neo Rage X.

So as for quality, I have to say I'm very impressed. After a lot of adjustment the only issue I noticed was that sometimes when backgrounds scroll you get a bit of...I don't know the correct term, shimmer? Even that is pretty minimal. You'll never notice it in KOF, and you certainly won't notice it in Bomberman or Super Baseball 2020, but it will show up in Metal Slug 3 or Pulstar because the BGs are so detailed. Other than that...I literally have no problems with it whatsoever. No delay, no scaling artifacts, nothing. The thing is amazing.

Is it perfect? No, only a large flat CRT is perfect, but for those who don't have an extra $700 and a titanium spine this is a pretty good substitute. It must be an absolute God send for operators. Seriously. You can replace a blown out CRT with this and some random LCD for $300 or less.

Best thing? Its $35. $35! Incredible!

 

[Hewitson]

You can replace a blown out CRT with this and some random LCD for $300 or less.

While I don't doubt these devices are good, you can easily replace a CRT for less than that. Tube from TV on the side of the road, brand new universal chassis to suit and you're done for $145AUD.

I've heard there is places in the US which provide similar chassis matching services. Tell them how many pins on the CRT, horizontal and vertical yoke readings, and they can configure the chassis to suit just about anything but Sony.

 

[SignOfGoob]

While I don't doubt these devices are good, you can easily replace a CRT for less than that. Tube from TV on the side of the road, brand new universal chassis to suit and you're done for $145AUD.

I've heard there is places in the US which provide similar chassis matching services. Tell them how many pins on the CRT, horizontal and vertical yoke readings, and they can configure the chassis to suit just about anything but Sony.

Yeah...that requires a dual class master technician/dumpster diver. (A guy with a two year degree also picks up garbage from the side of the road and tries to salvage it for parts.)

Most arcades only have half of that equation at this point; a crack addict installing bootleg Happ parts into Golden Tee machines for $8 an hour.

 

[distropia]

In my experience, this converter is great but for that... "shimmer" that I prefer to call "scrolling artifacts"...

Take a look at this video:

http://www.youtube.com/watch?v=-40gDZey0e8

(I only had my phone video recorder, so forgive me about the quality)
Video explanation:
This is a detail of the Samurai Showdown IV intro on a NeoGeo MVS connected to a VGA monitor through this converter. You can see some pixels jumping on the japanese characters as the background moves. These pixels should remain still. The moving background is normal, is part of the intro animation.
The same occurs with the flashing "INSERT COIN" letters in every game.
Take note that this is a zoomed detail (not the entire screen).

The gameplay is not affected. You have to be a hardcore gamer to notice it (I am).

Fortunately with this converter, there's zero dot crawl and moire (that's mainly caused by interferences and bad shielding in the analog signal). It's another kind of problem. The pixels get "attracted" to the next upper line if that one is moving. Since it is a very complex converter with a processor and memory, I think the problem may be related to internal buffers or software bugs. I guess if it's upgradeable.
I got in contact with the seller and he only told me "press AUTO button for 5 seconds", the results were better but the effect remains. Also I told about the possibility of erasing that big chinese letters appearing at the boot of the device. He didn't answer...

Of course, I've talk about the worst facts of this converter, but the overall is great.
More opinions?

 

[SignOfGoob]

I'd like to know what systems other people have used with this thing, what success they've had, and what modifications they had to do to get it working.

What I've tested so far:

MVS: Very very good. Brightness is perfect with the best picture visible with the pots at about %95. Only the shimmer is problematic, and its really not that bad at all, honestly.

Saturn: Tapped RGB from the board, no modifications needed. Image is fucking amazing (except for the shimmer).

PC Engine: couldn't sync, image seen only briefly. Will build amp and test again.

Genesis 1: Image couldn't sync, and when briefly seen it was very dark. Will modify RGB signal with the resistors/caps seen in UK SCART cable schematics and try again.

Game Cube: Using OEM component cable things look really good. 3D games make the shimmer really hard to notice.

PS2: Using OEM component cable, same results as GC.

 

[Tempest]

Anyone else tried a PC-Engine with this board? Is the signal just too weak to use even with an amp?

Tempest

 

[Xian Xi]

For the PC Engine I've always had to build amps no matter what encoder.

 

[Tempest]

That I know, but for some reason the two schematics for amps out there don't like the GBS-8220. No idea why, but is appears to be a sync issue.

 

[Tempest]

Bump?

 

[Hewitson]

Didn't realise that was a request for help.. Got a link for these schematics?

 

[SignOfGoob]

I built this one:

http://www.gamesx.com/wiki/doku.php?id=av:n64rgb-amp

and this one:

http://www.gamesx.com/grafx/pce_rgb.jpg

These amps are built to boost the brightness on analog TVs and monitors, which isn't a problem on digital transcoders. The problem is the sync. A straight unmodified PCE signal jives with an XRGB no problem, but the GBS-8220 just can't hack it. The image will vary from zero sync to occasional sync of a frame or two.

The IC amp I linked to up there doesn't touch the sync, so that fixes nothing. The old PC Engine no Subete amp does boost the sync a little, but I'm not knowledgeable enough to understand if this isn't helping enough, or if its just making it worse.

 

[Tempest]

Tried the GBS-8220 last night with a SNES, SMS, and Genesis model 1. All had the sync issue Zeta describes where you see the screen for a split second and then it disappears and reappears intermittently.

I thought I had read somewhere that people have gotten the SNES and Genesis to work with this board which is why I'm confused. Could all these systems (SNES, SMS, Genesis, TG-16) be having same issue?

 

[Xian Xi]

Try building a small amp for the sync line, maybe the signal is too weak.

 

[SignOfGoob]

I did that before, but I'm going to try it again in a slightly different way.

BTW, as I mentioned before Saturn and Neo are %100 pure gold awesome. Its everything else that sucks for some reason.

 

[White Devil]

I have the GBS 8220. The PCB has v3.0 printed on it.

I have it wired to the RGB out via JAMMA harness which is attached to my MV-2f.

When I hook 5v 2a it outputs to a LCD just fine except that the shadows under characters in fighters seems to flicker.
When I hook it up to my 18" insignia CRT (from approx 2005) the picture jumps. I tried the auto button on the encoder, resetting it doesn't work.
I don't know what to try next.
Any suggestions?

 

[mikey]

The flickering on the shadows and what not could just be because it's taking an interlaced signal and making it progressive, so things won't always look totally like they should. There is some definite pixel jumping with this thing. I found that I had to put a sync stripper inline with the 8220 to make it work with most consoles. I did it based on the info found here http://www.mmmonkey.co.uk/console/other/sync.htm

For other consoles like the PCE, the RGB amp schematic found at gamesx was still necessary on top of the sync stripper (specifically the sync amp to get a steady picture) Not sure if some other jamma boards need a similar setup. I know I tested the 8220 with a CPS1 and needed to put a sync amp in the circuit to steady out the picture.

Not sure if this info will make any difference if it's working fine on one screen, but I hope it helps.

 

[White Devil]

Thanks Dude, however, i was not thinking correctly and i didn't realize i already had a power source to my 8220 and plugged a different one in as well and fried it. any suggestions other than buying a new one?

maybe with the new one i'll get something more reputable. just got the x-men 6 player, primal rage and time killers PCB's, so i need something that will work with the (2) former.

 

[SignOfGoob]

Thanks Dude, however, i was not thinking correctly and i didn't realize i already had a power source to my 8220 and plugged a different one in as well and fried it. any suggestions other than buying a new one?

If you added two power supplies to the same place that shouldn't have blown anything unless one of them had too high a voltage.

maybe with the new one i'll get something more reputable. just got the x-men 6 player, primal rage and time killers PCB's, so i need something that will work with the (2) former.

There are certainly better scalers out there, but nothing at this price. Nothing at four times the price even. This thing is CHEAP and everything else is EXPENSIVE.

Options:

A better scaler new: $400+

A better scaler used: probably $150 at least

Get used to the GBS 8220

Regarding shadows: The flicker based shadows and transparencies used so much in the 16-bit era (ie: character shadows in KOF) aren't correctly rendered with this unit. Everything else is pretty great though.

Regarding your CRT: I haven't had any issues hooking this to any CRT. You need to be sure that the problem is with the GBS and your CRT and not between the source and the GBS. Turn off the source and bring up the menu on the GBS. If your monitor can maintain that then it should be able to display any game. I guess you could try potting down the colors but I think that only helps with to maintain the signal between the source and the GBS.

 

[Billkwando]

I hate to bump an old thread, but I've been looking at this board (GBS-8220) because I'm interested in getting scanlines on my plasma, and it appears that none of the SLG products work with 240p sources.

I emailed Jochen about the SLC HD= and he replied:

The unit is meant for 480p sources. 120 scanlines are only applicable for 480i. It covers 480i as side effect, but was never meant to work with such sources. For 480i sources go with slg in a box. For 480p yuv slg hd rocks.

The idea is to run my RGB to YUV (CSY 2100 clone) to this board via component, then run it through one of the SLG doohickies and hopefully figure out some way to convert it back to component (or add the SLG later in the chain, see below). Minus the foggy part at the end, is this idea completely retarded?

I'm basically just trying to slap something together on the cheap, but it sounds like all that chaining crap together would cause some signal degradation? I don't think I need the whole SLG IAB setup, and I'd rather be able to buy the parts piece by piece so I can spread out the spending.

If it actually worked, I could hook it to my component switchbox, then run my entire component setup through the SLC HD= and put scanlines on whatever I wanted.

Are there any more direct ways of going about this in a bargainesque fashion?

 

[SignOfGoob]

If you are picky enough to demand scanlines then you probably don't want to use this board since it fucks up shadows pretty bad.

Just save up for an XRGB or get a SD display.

 

[Billkwando]

If you are picky enough to demand scanlines then you probably don't want to use this board since it fucks up shadows pretty bad.

That is a valid assumption! Still, I played with moire and crap for years and still have a debug chip mod, so I'm no stranger to compromise. Has anybody made a video showing the defects? It would be nice to get an idea of what it looks like.

I'm guessing you're probably right, but I have a nice 36" crt I could use if I really wanted to, just not downstairs. Now that I think of it, that thing would probably play hell with my saturn and genesis games. Didn't they use transparency effects all over the place? (Nights and such)

 

[synrgy87]

i have one of these and its not bad, works great with SEGA Saturn and megadrive, megadrive, i did need to do the sync mod on the MD from mmmonkeys site to get it working well the MD/Genesis mk1 uses comp video as sync and the dedicated sync pin on the av port is actually connected to the comp video too. why they done this i dont know.

my MK1 sega master system works well with it too. no noticable delay as far as i've seen. it's got a few handy settings to play around with. i found it works best at 640x480 or 1024x768

also i've added a lm1881 to the GBS 8220 and a RGB scart female socket added.

 

[Billkwando]

the dedicated sync pin on the av port is actually connected to the comp video too. why they done this i dont know.

Could you elaborate on this?

Do you have any pics of the mods you've done, or video of what it looks like, quality wise? How does it look with component video sources? My assumption is that I could skip all the sync stuff if I went component rather than RGB, and I'd like to know if that's correct, and if there would be any noticable loss in quality (other than the aforementioned shadow effects).

Starting to think it might not be worth the headache for an effect that I'm not even sure I'll like. As great as the Neo looks through component, if you stare hard at the detail it looks pretty crunchy and I'd like to do something about that (if it doesn't involve spending the same amount I could on a new Neo, or jumping through fiery hoops). Been looking at old equipment, but then you get into BNC connectors and complex setups....as the folks across the pond would say, it does my head in. It would be fun to explain to my wife why there's rack mount equipment under the DVD player.

I think I'd need an extra power strip just to hook all the extra crap up too.


Edit: Oh and I have an MVS machine 15 feet from the TV....WTF is wrong with me that I'm even bothering with this? RGB, I stab at thee! I guess I just prefer sitting down most of the time.

 

[synrgy87]

Could you elaborate on this?

Do you have any pics of the mods you've done, or video of what it looks like, quality wise? How does it look with component video sources? My assumption is that I could skip all the sync stuff if I went component rather than RGB, and I'd like to know if that's correct, and if there would be any noticable loss in quality (other than the aforementioned shadow effects).

i don't have any pics of my mods on the MD or video for that matter lol sorry, i don't use component, just RGB scart, i have seens some videos of people using the GBS 8220 with component output from the nintendo wii and it did look pretty nice although i've not seen this in person. everything i have is RGB SCART.

if you do use a GBS 8220 make sure the power supply is decent 5v 2amps but i've use an ATX power supply for mine it works well. can accept 12v but gets very hot and not recommended for long periods (or at all)

have also seen people doing RGB scart > component > 8220 but im not sure what if any the benefits of this are.

mods i done:

sync stripper
http://www.mmmonkey.co.uk/console/other/sync.htm

i added mine to the GBS 8220 board.

MegaDrive/Genesis sync mod.
http://www.mmmonkey.co.uk/console/sega/md-sync.htm

i've not noticed any quality loss but i've not used it a lot i initially got it to set up a dedicated retro game LCD monitor but have not gone much further with it as i've been sidetracked by all things MVS and also picked up a old school sony trinitron CRT from 1994

 

[Billkwando]

I emailed Fudoh, who runs the Upscaler/Scanline info site http://retrogaming.hazard-city.de/ and asked for his advice, cos I was gonna buy an NEC IDC 2000 line doubler that was on Ebay, and he emailed back in, like, an hour! This was his response, in case it helps anyone in my situation:

Hey Bill,

first things first: does your Panny still have a VGA input ? If yes, it would
make things a lot easier. If not, well, more complicated

Second, I have no experience with the NEC IDC-2000, but I just a look at the
IDC-3000's manual and the RGBHV input there is just for passthrough purposes
(and it's meant for 480p or higher resolution signals). I assume that it's
the same on the 2000, so you're out of luck with your RGB sources. Also the
CSY-2100 clones are just for 15khz source, so you can't connect a linedoubler's
output to it.

So, in essence, the IDC-2000 is good for s-video in only and you can only use
it if you got a VGA input on your TV.

Your best (budget) option is an iScan Pro (which usually go for $50-60). They
got a component input and the output can be configured for either VGA or
component. If you got a VGA port you can pair it up with a SLG3000 or MiniSLG.
For component you can pair it with a SLG-HD.

http://www.ebay.com/itm/261239056689

$50 buy it now are very fair for a unit like this and especially in this
condition with all the accessoires. The iScan Pro also properly handles 240p
material, so drop shadows and flicker effects work and look as they're
supposed to.

Hope this helps!

Tobias

Needless to say, I took his advice!!