[Yaesu] FT-990 Filter availability

[Harris Ruben]

I've acquired a second FT-990 in magnificent condition but it has 
neither optional filter (my other 990 has both). I'd like to get the 
thing up to high performance.

1. What should I add, and where can I get it?. I haven't had an 
answer to my request to Yaesu yet.

2. Can I swap the board with the filters from my old 990 without 
further adjustment? Then I can return my old (drifting slightly) 990 
to Cerritos for a new TXCO or their repair and whatever upgrades it 
may need. I could install the filters myself, I'm sure, but wouldn't 
want to do the unsoldering/soldering of the TXCO myself.

Any other suggestions??

Thanks
Harry N2ERN