Antifrodis
Member
Here's my latest problem. I haven't run into something like this before.
I recently decided to swap my Track & Field guts from one beat up T&F cab to another. The WG 19k4906 in the old cab was giving me trouble. The WG 19k7901 in the "new" cab was working great with a JAMMA setup. I removed the JAMMA harness, and rewired things using the harness I had for T&F. Everything booted up fine, except that I seemed to have some interference rolling down the screen on the 7901. I immediately thought there was a grounding issue. There was no ground post on the power plug. Furthermore, it appeared that the monitor housing was not grounded, as I found a loose green wire with a terminal at the end. This same wire in my other cab is attached to a screw on the right side of the monitor frame. I replaced the plug with a 3 prong plug, and I attached the green wire to the monitor. I powered up and blew the fuse on the monitor chassis.
My next move was to discharge the monitor and change out the fuse. Then I got the power schematic from the manual and used that, in combination with my old cab, to try and make sure everything matched up. I re-soldered the wiring on the fuse block, removed a workaround that eliminated the original top power switch and got the switch back into circuit. I tested the switch for continuity and it seems to function properly. I got everything wired back up and made sure everything was grounded as it should be (coin door, control panel, monitor chassis, iso transformer, switching power supply). I powered back up without the PCB connected to the harness and blew the fuse on the chassis again.
So my question is, would there be there any reason why I can't ground the monitor housing? Is there any reason I shouldn't? It appeared to be working fine without the ground, other than the fact that the picture was noisy. Furthermore, the ground wire wasn't connected to the monitor frame when it was a JAMMA cab, and as far as I remember, there was no noise on the monitor when it was JAMMA-tized. I need some ideas as to what to check next.
Thanks for any advice in advance.
I recently decided to swap my Track & Field guts from one beat up T&F cab to another. The WG 19k4906 in the old cab was giving me trouble. The WG 19k7901 in the "new" cab was working great with a JAMMA setup. I removed the JAMMA harness, and rewired things using the harness I had for T&F. Everything booted up fine, except that I seemed to have some interference rolling down the screen on the 7901. I immediately thought there was a grounding issue. There was no ground post on the power plug. Furthermore, it appeared that the monitor housing was not grounded, as I found a loose green wire with a terminal at the end. This same wire in my other cab is attached to a screw on the right side of the monitor frame. I replaced the plug with a 3 prong plug, and I attached the green wire to the monitor. I powered up and blew the fuse on the monitor chassis.
My next move was to discharge the monitor and change out the fuse. Then I got the power schematic from the manual and used that, in combination with my old cab, to try and make sure everything matched up. I re-soldered the wiring on the fuse block, removed a workaround that eliminated the original top power switch and got the switch back into circuit. I tested the switch for continuity and it seems to function properly. I got everything wired back up and made sure everything was grounded as it should be (coin door, control panel, monitor chassis, iso transformer, switching power supply). I powered back up without the PCB connected to the harness and blew the fuse on the chassis again.
So my question is, would there be there any reason why I can't ground the monitor housing? Is there any reason I shouldn't? It appeared to be working fine without the ground, other than the fact that the picture was noisy. Furthermore, the ground wire wasn't connected to the monitor frame when it was a JAMMA cab, and as far as I remember, there was no noise on the monitor when it was JAMMA-tized. I need some ideas as to what to check next.
Thanks for any advice in advance.