I have a Valiant I that I'm rebuilding from the ground up.? In the original schematic, Johnson used a double fused plug with two 8A fuses. ? I assume that was because the plug was non-polarized and the double fuse arrangement was used to insure that that the hot side of the power line was fused regardless of how the AC plug was inserted in the socket.? I plan to use a 3-wire 16 AWG power cord for my rebuild, so that isn't an issue for me..
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I don't know whether the earliest version of the Valiant had the 1.6 amp fuse in the LV transformer primary or not (mine had it).? Except for the antenna relay jack, the only things fed by the line cord are the two transformer primaries.? Am I to assume that the primary of the HV transformer could potentially draw 6.4 amps?
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As part of the rebuild project, I plan to fuse each transformer primary independently for safety reasons.? What size fuse should I use for the HV transformer primary?? Is 6.4 amps reasonable, or is that overkill.? The transmitter isn't built yet, so there's no way to get a ballpark value for a HV primary fuse value.? I am replacing the old 866 MV tubes with 3B28s.
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Another concern:? Since the Valiant design switches the primary of the HV transformer, I can see the possibility of some significant switching transients when the transmitter is keyed.? Should I use a slow-blow fuse for the HV transformer primary?
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I would appreciate your input on this issue.
Thanks!
Mike Harmon, WB0LDJ
mharmon at att dot net
