I disagree with Guillaume. I have a 2.8E which has a good meter. The 2.8 uses a selenium meter which requires no battery. Later models use a CdS meter which does. I am not sure on the 3.5F - does that have a selenium meter or CdS cell? If the latter, check the battery. With either, the problem should be repairable. With a selenium, a new cell could be required, but that doesn't run that much. I believe a good camera repair tech should be able to handle the repair.
Steve Perry