Its quite possible it will still work with IC8 broken, there is plenty of gain in the signal path to make up for it. The ALC will crank itself up to compensate as far as possible.
Given the poor reliability of the OM345s, they must be suspect. There is a thread here that describes a way of "fixing" them which works some of the time.
https://www.vintage-radio.net/forum/...=100840&page=2