Hi all. I have a very early FT980 (in fact I have two - one with an Rx fault with LSB and one with a Tx fault - intermittent RF power out).
For the Tx problem rig, when I Tx using FSK mode with 50 Ohm dummy load and advance the drive control - SOMETIMES - meter 1 can go full-scale (normal) and my power meter shows a steady 80 Watts Rf out. (a bit low).
OTHERTIMES there is no movement on meter 1 even with Drive control fully clockwise and no Rf out on my external power meter.
I noticed with the drive control fully clockwise on Tx, quite a loud hum from the area of the PA/Power supply which I have proved is 100Hz.
This sounds like too much ripple from the two smoothing capacitors (18000uF 50VW, which i will try to change) but I wonder if this is the cause in the intermittent problem or whether this is something else? (e.g. the tantalum capacitors mentioned by EA1FC?
Thanks for any comments
Peter G0LQU
