Quoted from vwallat99:Both my guns can't hit the lower target for calibration. Before the Green gun on the left could do it and the old orange gun as well. Now neither can hit it. They both shoot fine for the left top target which is why I'm leaning on a monitor issue.
How do I know this is a bad I/O board if I'm still able to get the upper left target and not the lower right?
I had a similar issue. The monitor was OK but I like nice and clear so I put in a brand new monitor and my problem went away. The monitor has to be good in order for the guns to register. Calibration was constantly off and couldn't calibrate sometimes. Also tried a new gun with no help until I replaced the monitor. Not saying you have to replace it but my guess its related to the monitor so maybe a rebuild is in order.