GE Master II Frequency Elements

[scsmh at GF-WAN.af.mil]

They are actually called ICOMs in the technical literature,
but asking for ICOM information could result in confustion.
Anyway, I'm working on a dx packet cluster node here in 
Grand Forks, ND.  Had a GE Master II donated by the county
EOC Office.  Where can I get channel elements/crystals/ICOMs?
Any source with price guess will be appreciated.

73 de Bob nd1h