Beauty is in the eye of the beholder. I wouldn't be afraid to buy a 746PRO. I bought a 746PRO 3 years ago and it has been trouble free. I have used it from 160M to 2M. I have worked 224 counties with a vertical. Works very well on PSK and RTTY also. I'd buy another one.
They sell complete power supply boards with new caps. They also have softstart and a driver board for the relay. I installed all of the above when I restored my SB-200 (that I built in 1968). The SB-200 is going strong - putting out a solid 600 watts.
I am having the same exact problem as Cliff. Cliff what was the final fix? Did you also replace the tube? Where did you get the parts? History: I am trying to fix an AL-80A for a friend. First I had to replace the antenna relay (bind) and the zener diode. Then the QSK board proved to be bad and I disconnected it. The amp then worked until it arced and I had to replace the meter diode. Worked until it arced again. With a new diode, key down for 30 second and the plate glows red and then it will arc.
I will try adding the resistor, caps and a heavier diode. Any other ideas???
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