GBS-8220, 23DB Connectors and Leads

[danko]

Other questions do not have a 680ohm 1/2w have a 1/4w is it a problem?

[Stedy]

Originally Posted by danko

Thanks, at the moment do not have a 5v 2a psu, works with 12v 1a supply?

It should do. The newer board are labelled up as 5-12V input. It only uses 0.4@5V or ~0.25A@12V so your supply should be fine.

More info on the boards here:
https://github.com/ramapcsx2/gbs-control/wiki

and my own blog:
https://ianstedman.wordpress.com/gbs-82xx-experiments/

A 1/4 or 1/2W resistor will be fine, worst case power dissipation is 0.025W

Quote:
Originally Posted by danko View Post
Thanks, at the moment do not have a 5v 2a psu, works with 12v 1a supply?
Use only 5V or you'll break it.

No you won't, the newer boards have switchmode converters which are more efficient and they are clearly labelled as accepting 5-12V input. I've run mine for hours from a 12V plugpack.

[danko]

@ Stedy

Thanks for your info,have a 5V 5A power supply working good,the problem is the lead test use original wire connected at P11 into a DB25 cut connector is not great, get a great result with a shielded rgb scart cable, according to you if build a good VGA to DB23 cable i can improve the quality ?

[ Show youtube player ]

[Higgy]

Guys,

A lot of work has progressed with the GBS-82** devices, carrying on from Stedy's and others work. There are a number of separate GBS threads which I have dropped in the info below.

@Stedy - I don't know if you have seen this (Edit - I see you linked to the Github page!)

https://github.com/ramapcsx2/gbs-con...d-the-Hardware

It requires soldering work to get the best out of it, but the mods work really well. It seems the actual Scaling chip used is very competent, its just the PCB designers didn't make the best job and they chucked on components without the correct value.
I am not an electronics buff, but the (German?) guy who took over the project from the original Aussie (which used a RPi) seems to know his stuff.

I don't think anyone has done a Youtube video of the Web UI control yet, but the User ChrisG has made some videos:

[ Show youtube player ]

[danko]

I thought it was the flying cable I used to do the test, I created a vga cable with a db23 connector but the image quality is the same as before you always notice the interference ...

[Vitalic66]

Hallo all.

I found this thread googleing for the tv5725 ic. At the moment i try to copy the layout of a similar board (HDMI version).

I already have a pcb that is a 1 to 1 copy. So i desoldered all parts from the original one and resoldered them on my pcb. But no picture..

I tried this several times right now and checked and rechecked and rerechecked my pcb layout.

Does anybody have a schematic of the MS9282 ic? I can't find something via google. That is how i came here. Didn't also find schematics for the tv5725 and myson ic except here.

There is also another 10 pin ic next to the MS9282 for which i can't find any information.

The reason why i do this is to integrade this pcb layout into a bigger one i design for myself. The first version when i did not make a 1 to 1 copy produced a very very green picture with many artefakts but it worked.

Regards

[rabidgerry]

Got my GBS 8220 up and running today! It was tricky at first and I didn't realise I could switch the menu to English so I had made all my adjustments by trial and error!! But I got it working and all seems good so far. Used a Nokia 5v phone charger I had lying around to power the unit. It supplies 5v and 800ma. It originally had a tiny pin connector on the end but I cut it off and soldered it to the supplied power plug lead that came with the board.


When I get the time I shall do the shielding over the ram traces to cut back on unwanted noise.

[rabidgerry]

So having used the GB 8220 for the last few days I've decided there is too much weird artefacts on my TV.

I tried the shielding fix and not sure it helped.

Here are some pictures to show what I mean. It's like a gradient effect in the back ground and is more noticeable in some situations more than other. Playing stunt car racer for example looked terrible, and there was weird stuff happening during in game play, like graphic break up when there was a lot of movement. Playing something like Mortal Kombat seemed a lot better, not so much movement distortion but the weird gradient in the background was there depending on the background.

Anything can be done?

Got contrast and brightness and saturation all up pretty high. Can't have the sharpness lower than 5. I prefer it on 7, but could tolerate 5 if I had too.

[amigoun]

GBS with stock firmware is not good for 240p content. There is a replacement firmware called GBSControl project that optimizes the device for consoles / retro computers. I have build the adapter and GBS performs much better now.

[rabidgerry]

Ahhh so this is you

http://www.amibay.com/showthread.php...s-amp-Adapters

and you are recommending this?

GBS-Control Clip-on Adapter for GBS 8200 (8220, HD-VC9900) Boards

Can you list the benefits for me? I will be happy to buy this from you with a little more info.

Thanks for this.

[amigoun]

Yes. Well, from the most useful features is smooth scroll (no tearing) because no frame conversion 50-60. Deinterlacing does not occur on 240p content (so no motion effect artifacts). Also better color reproduction and more resolutions presets. Picture is more clear, no verical bars. I also like the possibility to stretch picture both vertical and horizontal and others.

[rabidgerry]

Like the vertical textured bars that can be seen in the Mortal Kombat picture I posted above? You can see like vehicle artefacts in the navy background of the picture.

[amigoun]

Yes. I noticed them on your photo.

[rabidgerry]

Originally Posted by amigoun

Yes. I noticed them on your photo.

Ok well I will pm you a buy one from you. Shame I didn't know about this when I was in Prague lol. Could have picked it up from you.

[rabidgerry]

I have removed C11, anything else I should do for the removal of noise in the picture? Turned all the colour controls to the left also and then adjusted from there using the software. I think everything looks pretty well now but I do get the vertical lines at times, sometimes more visible than others depending on what's on the screen. Hope the GBSControl project will solve that though.

[danko]

@rabidgerry

Tested GBS with custom GBSControl fw?

[danko]

Tested GBS HD9800 V5.0 with GBSControl cfw on my Amiga 1200 and works without any problems,i removed a C11 capacitor from board (although I have not noticed any differences) make a cable VGA to DB23 cut (put resistor 680ohm 1/4w) centered the image with the webUI but i'm still not fully satisfied...........monitor tested is Samsung LCD TA350.

https://github.com/ramapcsx2/gbs-con...re-Mod-Library

There is an essential mod but i didn't understand how to do it
Add 100ohm resistor across sync and ground for RGBs input.
How to do this mod??

[danko]

With great surprise try to connect an old CRT monitor Samsung 753DFX the quality is superb !! gbs control is the best!

[rabidgerry]

Originally Posted by danko

@rabidgerry

Tested GBS with custom GBSControl fw?

Sorry for the late response.

Yes I got one initially from amigoun but that didn't work at all. So I took it upon my self to buy an Arduino board and start from scratch.

I managed to do it! I even managed to get it hooked into my wifi (trickier than I expected). Basically why I was unable before was I had to log onto my internet router and gran access to the arduino board. Anyways that allows me instant access to the control panel to control the board (size, presets, options). So once I got it hooked up and tapped into the control panel I was able to create some presets to suit my needs. Just to be clear, I could live with the GBS onboard firmware, it wasn't amazing but for the price I mean it can't be beat. Sometimes I would still need to mess with the setting as it could be a little tempramental at time but generally I was getting ok upscaling for very cheap and so much better than my composite output. So when I finally hooked the GBS Control to my board I got instant clarity, no noise, and no weirdness with fast moving sprites. So it basically eliminated a lot of stuff to provide a very crystal clear picture.

One issue remains

Veritical lines!! Of Jailbars as they have been described. These are faint, and I can tolerate them as they aren't always visible. However you can always see them for example on a grey blocks of colour on screen (like the road in Supercars for example). Now I think there are solutions to this and I would really like to know more about them but as of yet I can't make sense of one mod I have read about here:

https://github.com/ramapcsx2/gbs-con...ginal-gbs-8220

Scroll down to the GBS 8220 bit. It shows a picture of what has been done, but for me I cannot tell what it is or how to go about executing the mod. Now I can carry out mods to a degree and have tinkered a lot over the years but I have very little understanding of what it is I am doing half the time and looking at a picture like that just looks like blobs of solder to me so unless some comes up with a step by step guide I wont be able to even try this mod.

Overall though I would say the GBS Control is the way to go. I have since updated the GBS Control twice now since initially installing it so it seems rama is on the ball working on it fairly regular. It is certainly a worthy addition to any GBS 82** board. If those jailbars could be eliminated I'd say I had near perfect upscaled Amiga display. Good enough for me and I'm a picky bastard! Probably someone more demanding out there than me though

EDIT: If you need to know how to do the 100ohm mod just let me know and I will take some pictures.

[danko]

Hi, I don't know what problem you have, it works perfectly for me, rather post the pics and someone more experienced than me will help you.