Golden Axe video output problems

[Arm123]

Hey guys, i have 3 of these boards laying around.

I decided to fire them up and see if they work.  I cant seem to get any video from any of them.  It just seems as if there is no signal.  I know they are working cuz i get sound from my test rig and sound when i input coin.

From the pinouts i found, i cant seem to find a video ground.

Code: [Select]

Golden Axe   Pinout
-------------------

              Component Side   Pin #     Solder Side
          -----------------------------------------------
                         GND   1   A     GND
                         GND   2   B     GND
             +5 Volts DC   3   C     +5 Volts DC
             +5 Volts DC   4   D     +5 Volts DC
           +12 Volts DC   5   E     +12 Volts DC
            Coin Meter 1   6   F     Coin Meter 2
                                   7   H             
    Player 1  Switch A   8   J     Player 2  Switch A
    Player 1  Switch B   9   K     Player 2  Switch B         
    Player 1  Switch C   10  L     Player 2  Switch C
                                   11  M             
         Player 1  Down   12  N     Player 2  Down
              Player 1  Up   13  P     Player 2  Up
          Player 1  Right   14  R     Player 2  Right
            Player 1  Left   15  S     Player 2  Left
                                    16  T             
                                    17  U             
                                    18  V             
                                    19  W             
          Coin Switch  1    20  X     Player 1  Start Switch
          Coin Switch  2    21  Y     Player 2  Start Switch
              Test Switch    22  Z             
          Service Switch    23  a             
              Speaker (+)    24  b     Speaker (-)
              Monitor Red    25  c     Monitor Green
             Monitor Blue    26  d     Composite Sync
                          GND    27  e     GND
                          GND    28  f     GND


I take voltages coming from the pins on the board and they seem to be working (0 to 2V).  I am outputting to a HD15 cable, to a monitor.  All other games that i work on seem to work fine with this setup.

Is there somthing im missing here ?  This is just straight negitive / comp sync correct ?  Where should i hook up the Vid ground ?

[SailorSat]

Hook the video ground to any other ground.

[Arm123]

Hook the video ground to any other ground.

tried that...  no go  :-(

[Arm123]

Im convinced that its a video GND issue.

All three boards work the same...  I can hear all the demo sounds, but no video.

[SailorSat]

Even without correct sync you should see anything on the screen as soon as you connect on of the RGB Pins

[Arm123]

I connected my 1942 pcb and removed the video GND to see what would happen...  It behaves the same.  No video.

Iv been looking at pics of jamma edge connectors for sega system 16 boards, to see if it can help me figure out the correct pin.

As far as i can tell all the GND pins on the board are connected...  I can tell this by looking at the PCB as well.  So this doesnt help me.  Im gonna pull out a Shinobi manual., maybe that will help.

I must be missing somthing.  Iv never seen a game board with out a video GND.

[Arm123]

I just looked at the wiring harness diagram for shinobi...   It shows the GND from the video connecting to a non specific GND on the edgs connector.  So its supposed to be how you suggested.

However, i tried that and it didnt work.

Ill try again.

[SailorSat]

Hm... I've seen some Tetris bootlegs without a dedicated video ground.
I usually connect them to common ground.

Maybe not all ground pins are connected Oo...
Check with a multimeter.

[Arm123]

i checked repeatedly...   

[Arm123]

Found the problem...  was a grounding issue.

I found a cracked solder joint in my rig...  It was hard to find because it would show continuity, but i guess it wasn’t a solid connection.

It tipped me off when i left the board sitting on and moved the harness...  the picture showed up distorted !

All is well now, thanks for your help mate ;-)