I have two sets of FM 10 x 2 transmitters at my site. Each consists of two FM 10s configured in a combined system to produce approximately 16 kW of forward power. We had a power bump at our site the other day and it knocked out one of our transmitters. Please see the attached word document for more the diagnosis and solution to the problem.
The 46 watts of drive is within spec as its divided by the splitter to feed each transmitter. There are some additional losses in the cabling and CS says its within spec. Do you still have the initial test documents that came with the FM-20? Can you take a look at the drive numbers?
Other than the drive issues its on the air and making rated power and happy while its waiting for the IPA return?
The exciter used to typically run at about 48 Watts (and had since install). Our transmitter site does not have any air conditioning so it turns out that my predecessor had turned down the exciter power a couple of years ago after he had determined that it (the exciter) was running very hot. I guess the IPA was able to handle the lower RF drive level but a PA being used as an IPA substitute was not. It threw me off for a while during the trouble shooting process but eventually got it figured it out.
And yes, we are back up to almost full power now. It is also nice to know the procedure for using a PA as an IPA substitute so that an IPA loss is not as critical of an issue.