I got a double jamma apdator board for my cab and I have a weird issue:
When I use the double jamma adaptor I see a vertical
line (grey almost transparent) that wipes the screen
from right to left for the game that is hooked up on
the second connector. My monitor is mounted verticaly.
The image is stable (I tried to tweak the 'sync' pot
on the monitor anyway just in case but it still shows
up); this is an almost transparent bar that wipes the
screen very rapidily from left to right. I switched
PCBs and it is still happening.
If I use the same PCB hooked up to the main jamma
harness w/o using the double jamma adapter then the
problem disapears.
The voltage on the PCB is correct (5.09v). Do you have
any clue on what could cause this to happen ?
The monitor is almost brand new ( I bought it brand new last year). It's a WG 21"
arcade cab montor issue
I'm sure you already know this, but almost evey PCB uses a different vertical refresh rate. So matching boards that are similar is best when using these kinds of switchers. Its entirely posible you cannot run two completely different setups (like an ST-V on one side and a Seibu PCB on the other side) as one or the other game will have sync issues.
Given that, did you say the anomoly happens on only the second connector o the swithcer board? Did you try swapping the games around to see if that changes? Also have you tried putting a single game on the second channel (with nothing on the first)? What kind of double jamma adapter is it (where did you get it?) Make/Model?
Given that, did you say the anomoly happens on only the second connector o the swithcer board? Did you try swapping the games around to see if that changes? Also have you tried putting a single game on the second channel (with nothing on the first)? What kind of double jamma adapter is it (where did you get it?) Make/Model?
thanks for you help Dave , this issue is driving me nuts for the past 2 weeks. I tried the following things that did not work:
- two different double jamma connectors with the same result (one from MikesArcade the other one from Lupine System).
- Switch PCBs form connector A to B.
My PCB combination is 'Ajax' and 'Chopper I'. After reading you I tried to see if one PCB could be the "source" of the problem and it seem to be related to Chopper I so far. Chopper I displays fine but any PCB connected to the other harness will show the problem. I swapped it with EspgaludaII or Pink Sweet and there are no problem.
I have another question to ask:. I have 2 cabs and they work fine if only one is turned on at a time. When I turn them both on then a gray bar scrolls on both monitors (far more pronounced than the one discribed in my 1st post). I chekced the inside of the Cabs and they both have a line filter.
- two different double jamma connectors with the same result (one from MikesArcade the other one from Lupine System).
- Switch PCBs form connector A to B.
My PCB combination is 'Ajax' and 'Chopper I'. After reading you I tried to see if one PCB could be the "source" of the problem and it seem to be related to Chopper I so far. Chopper I displays fine but any PCB connected to the other harness will show the problem. I swapped it with EspgaludaII or Pink Sweet and there are no problem.
I have another question to ask:. I have 2 cabs and they work fine if only one is turned on at a time. When I turn them both on then a gray bar scrolls on both monitors (far more pronounced than the one discribed in my 1st post). I chekced the inside of the Cabs and they both have a line filter.
Unfortunately there are many things that can cause these and other problems...
* Poor wiring in your house.
* Faulty line filters in the cabs.
* Poor ground wiring in the cabs.
For the PCB issue:
* Bad filter caps on the PCB can cause this.
*
List of things to check/try:
* Borrow a UPS from somewhere and see if isolating the cabs from eachother or both from the house supply helps.
* Replace the line filters in both cabs
* Check the common ground on the PSU is connected to field ground (earth). Apparently this is done internally on some power supplies, and not others.
* Try using an interference blocker board - the strange JAMMA extension boards you sometimes see with lots of things that look like diodes on them. They reduce EMI leakage - small ferrite cores.
* Try replacing the filter caps on Chopper 1.
Sorry I can't give you a specific answer - I have a similar problem myself on two cabs. I used to have a cab that displayed interference lines on ANY pcb - I disconnected monitor earth to fix that. It WILL work, but it is not the correct solution.
* Poor wiring in your house.
* Faulty line filters in the cabs.
* Poor ground wiring in the cabs.
For the PCB issue:
* Bad filter caps on the PCB can cause this.
*
List of things to check/try:
* Borrow a UPS from somewhere and see if isolating the cabs from eachother or both from the house supply helps.
* Replace the line filters in both cabs
* Check the common ground on the PSU is connected to field ground (earth). Apparently this is done internally on some power supplies, and not others.
* Try using an interference blocker board - the strange JAMMA extension boards you sometimes see with lots of things that look like diodes on them. They reduce EMI leakage - small ferrite cores.
* Try replacing the filter caps on Chopper 1.
Sorry I can't give you a specific answer - I have a similar problem myself on two cabs. I used to have a cab that displayed interference lines on ANY pcb - I disconnected monitor earth to fix that. It WILL work, but it is not the correct solution.
System11's random blog, with things - and stuff!
http://blog.system11.org
http://blog.system11.org
thanks for your advices bloodfowers.I tried connecting the field ground to the common on the PSU but it makes matter worse actually. The black wiping effect is more pronounced. I improved the grounding on the double jamma connector and two improvements occured:
- The voltage on each PCB increased by 300mV. I used to have to set the PSU to 5.80v to get the correct voltage on both PCBs now I'm down to 5.50v.
- The wiping effect is far less pronounced than before; It's almost not noticeable. It's weird that I can only see it during gameplay. If I go into the PCB 's service mode and get into the color or dot cross hatch screens then I don't see the problem. It only occurs during gameplay.
I haven't had a chance to get a hold on a UPS yet. Regarding the filter caps on the Chopper I PCB, how can I identify them ?. There are 3 big caps and a couple of smaller ones. How do I determine which one to change ?
- The voltage on each PCB increased by 300mV. I used to have to set the PSU to 5.80v to get the correct voltage on both PCBs now I'm down to 5.50v.
- The wiping effect is far less pronounced than before; It's almost not noticeable. It's weird that I can only see it during gameplay. If I go into the PCB 's service mode and get into the color or dot cross hatch screens then I don't see the problem. It only occurs during gameplay.
I haven't had a chance to get a hold on a UPS yet. Regarding the filter caps on the Chopper I PCB, how can I identify them ?. There are 3 big caps and a couple of smaller ones. How do I determine which one to change ?