I wanted to thank everyone for their posts. I just recently ran across this exact same issue on my 706MKIIG and being I don't have a ton of knowledge in regards to electrical components I took it to a local buddy and he helped troubleshoot the radio. We managed to narrow down the problem to C335 AKA VCO2 trim-cap.
Following our findings I called Icom only to find out that the board is a WOPPING $220
So I started searching around and found this forum and saw you guys were nice enough to post the part number for replacement part
Thank you very much for posting in regards to the problem and posting the replacement part number!
I have ordered the replacement caps and will be replacing them as soon as possible and bringing my wonderful 706 back online