I have an 8640b with issues. As frequency is increased in each range,
it falls off to nothing or very low at the high end. Low end seems to
work ok. I aligned the two seperate detents on the range selector
switch, but still the same problem. Is this a common failure, or am I
going to have to dig deeper? Sorry this is so vague, I really haven't
had time to tear it up, but I can't keep up w/ all the customer
equipment and repair all of ours at the same time, you know how it
is..
Steve