If you've been following my latests posts, you'll know that during the last V-UHF contest I detected reduced output power on the 70cm band in my FT-817ND. The output power was only about 60% of the maximum 5W in SSB and CW, but in FM mode it reached 5W. This problem only happened on the 70cm band. On all the other bands, the radio reached 5W output power in every modes. After spending some time studying the service manual, I came to the conclusion that the problem was that TX gain in the UHF band was too low. This is a software calibration parameter, so, in the end, fixing this problem has been rather easy.
On last Saturday's V-UHF contest I observed reduced output power on the 70cm band in my FT-817ND. I spent the next day poking inside the radio with the oscilloscope trying to see where the problem was. While doing this, at some point I completely lost output power in all bands. I found that the problem was that F1002, an SMD fuse, had gone open. Here I describe said fuse and the replacement procedure, which I found much easier than I thought.