[TenTec] Omni V narrow (model 218) 9 MHz crystal ladder filter option.

[Doug Gomez]

I installed the narrow filter board when I purchased the rig new in 1990.  Recently, I've noticed adding this narrow filter mutes the receive signal almost completely when any filter selection (2.4, 1.8, .50 or .25) is selected  It did not do this in the past.  The jumper is in the correct (pins 2&3) location for this filter, as well.
Anyone having experience with this board and which component(s) went awry would be greatly appreciated.  
Thank you, Doug, KC6RCM