[Elecraft] KAT500 EEPROM Problem

[Ed]

Our club K3 is connected to a KAT500, which is connected to 3 antennas (ANT1: Zero-Five vertical, ANT2: DXCC fan dipole, ANT3: 135ft doublet.  Yesterday I was using the K3 on 6 meters with ANT 1 and ANT2, which were not designed for 6 meters.  The KAT500 was able to tune for a low SWR, and the TX power was about 50 Watts.  No problems occurred during the 6m net, but after the session was over, I noticed that I could no longer select ANT 3 on the KAT500, regardless of the band.  
I ran the KAT500 Configuration Software, and verified that ANT 3 is configured for use on all bands but 6m.  The configuration SW "Operation" tab could not select ANT3 either (the K3 was turned off).  
I tried to save the current KAT500 configuration, but a "Save Configuration Error" box popped up after about 10 seconds, which stated "No response to Read EEPROM block".  I repeated the process a few times, and the same error occurred each time.The KAT500 firmware is at v1.75.  I suspect that RF may have gotten into the KAT500 and corrupted the EEPROM.  I'm not sure what to do next.  Has anyone encountered a similar problem?  
Thanks & 73,EdN2BHD