gbs 8200 in high impact football

[Dwatters]

to start with im completely new to arcade repairs and this forum but i recently came into a williams high impact football and a sega shooting master. i started with the high impact and now how the board fully functioning from what I can tell as it has all attract audio working. I dont have a monitor for either of these so i picked up the GBS and wired that in.

upon power up the lcd displays the rom check but never goes any further. the game continues to boot and move into attract mode but the screen stays frozen. the only way to get it to change is to unplug and re plug the sync wire and then itll show a now image but it is still frozen on that new on. i cant get a constant video out of this thing. im completely at a loss now as the manual doesnt give any help.

i have already tried the board reset on the gbs where you hold the button down for 8 seconds, all that does is gives me a new frozen image. ive also tried the auto function on the board and again nothing different. ive ran it off a 12v3a power supply then wired it into the 5v15a inside the cabinet and no change either. any one have any idea what i can do here?

 

[nobody]

From the master: set vertical position to a value >= 28

 

[Dwatters]

Same issue. The screen is still frozen even tho the game continues to play

 

[stj]

so you know, the gbs actually only needs just under 300mA
using a big psu just for it may make the psu unstable.
i power mine from a usb phone charger or a flying lead from my jamma harness.

 

[Dwatters]

Ive tried that also now. I was told on another forum that the gbs needed a minimum of 5v 2a power lol but so far I can still get nothing but a frozen image of whatever the screen was on when I connect the sync line

 

[stj]

i'v seen that crap posted,
but as i was curious - i ran mine through one of those usb dongles with an ampmeter in it.

i dont know why your sync wont lock, but maybe your sync voltage is too high - the gbs shouldnt get more than 3v
some people put a resistor between csync and ground.
https://github.com/ramapcsx2/gbs-control/wiki/Arcade-Boards

 

[Dwatters]

Yeah I'll try that next. I did notice if I ground sync it will of course change the image to the next frame but every so often I touch sync to ground it will give me 1-2 seconds of movement on the screen. Also before I forget I have 3 gbs and all 3 give the same issue. I used a multimeter and sync was 2.8v

AAlso does anyone know what the second led on the high impact board is? I know the one that's always lit is the 5v but there's another not lit below it

 

[stj]

from memory, one shows the running status of the cpu, so it should be constantly flickering or dim.
if i'm thinking of the right board!

 

[stj]

just looked at the schems - the sync output is 5v!!!!!!
try this:

 

[Dwatters]

o wow ok so is that between sync and ground or between sync out from the board to sync in of the gbs? also forgive my ignorance to the picture lol im still learning to read schems correctly, do i need the 680/820 only or that between the line and then 2k to ground?

 

[Dwatters]

I gave it a shot with 2k to ground and 820 between the sync line and it seems closer. The image will change randomly but only to another static image unless I unplug and replug sync.

 

[stj]

the 2k is built into the gbs
you just feed the sync through an 820 ohm resistor in series.
or even a 1k in series

 

[stj]

btw, if you buy any more then get the gbs8220 - the double output model fixes a lot of design errors.

 

[Dwatters]

put the 860 in series and no change. possible that running the 5v sync through it could have damaged it?

 

[stj]

test it with something else.
btw, what sync signal are you using - that game has 3,
and where are you putting it into the gbs?

 

[Dwatters]

Pin p labeled as video sync. I didn't know of any others
Going into the Grey wire one the gbs. I've tried its original spot (s) hs and VS on the gbs

 

[Dreygor]

I am watching this thread just in case I run across some issues like this.

I know this post doesn't help with your situation much but it may be an option is a regular GBS-8200 does not work out.

The reason being I just received a Modded GBS-8200 (thank you @Derick2k for showing it to me) and next week I am going to hook it up to see how it works on out putting video to my Chewlix cab.

Here is the link to where I boughtit and a run down of what the mod entailed..
https://www.tindie.com/products/chipnetics/modified-gbs8200-rgb-to-vga-converter/



The plan is to use an Irken Labs JAMMAfier and one of these to output my PCBS and systems like Neo Geo , S-TV and stuff like that to my JVS cab.

 

[Dwatters]

i was reading alot about the firmware mods and esp addons to the gbs i just didnt know it it was for arcade use or just converting it to console use lol. if its arcade use ill get it all ordered and assemble it......once i can get this working lol. i wonder if the custom firmware would benefit my issue in any way. i may flash one just to see.

test it with something else.
btw, what sync signal are you using - that game has 3,
and where are you putting it into the gbs?

where can i pull the other sync signals from? i dont see any other listed on the jamma connector. i also now have a monitor but its far from usable. i just finished a full recap and new transistor but i still have no power on that. ill probably make a new thread on that soon its an imperial with a jc-tron board

 

[stj]

if you go to a good manuals site like basement arcade, the high impact manual has schematics and connectors listed at the back

 

[Dwatters]

I tracked them down to j5. I tapped rgbhv from there and it's different but still just as bad. Now on the rgbs input I get flashes of colors or a dim out of sync rolling screen. If I go to rgbhv I get a solid color.

H sync is .48v and v sync is .18v

Im guessing these are to low to work?