Hello, I would try disconnecting the HV AC from the transformer to the PS
board, so that the only thing connected to the line voltage is the filament
transformer, and the HV transformer. Protect the ends of the wires from the
power
transformer. Turn the unit on see what happens, switch to SSB, see what
happens, if OK, then problem in PS somewhere. If you still blow a fuse at this
point, your problem is with the line voltage to the transformer, it could be
that
the SSB tap has a short or perhaps the cw/ssb switch is shorting the primaries
together in the ssb mode. This can be checked with all wires removed, and
check switch with ohm meter. If all checks OK, then you reconnect the HV AC to
the PS board, and it blows a fuse then, if may be a leaky cap to ground if you
have checked all else (diodes, etc). You may want to disconnect the HV and
B- from the rest of the circuit also to see if perhaps there is a problem AFTER
the power supply as well. Foe example, a shorted blocking cap will cause the
mains to blew right away. Key is to "isolate"!! Good Luck 73 Louie
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