Bodger's transformer Installation Lafayette HE-40
When it comes a ham radio equipment I cannot help wondering if it is actually a license to commit atrocities again radios ?
I have a Lafayette HE-40 these came out the Trio factory of Japan back in the day under various names Hallicrafters S-120, Star-Line SR-40 and in England the HAM-1
The radio I have is in a bit of a state all the valve missing and a really appallingly installed transformer I think these were a AC-DC set originally designed for 120 AC. I haven't found a picture or circuit for the HAM-1 version sold in England so dont know if it was AC DC or transformer circuit. But this has a really badly installed transformer of the 230/120/6.3V type.
The original radio used series strung 12 volt valves I have tried to find 6 volt alternatives that I plan on using with the 6.3V transformer . I couldn't find a direct replacement for the output valve 50C5 and I am using a 6CU5 would this be OK ?
Currently the phantom has wired all the filaments in parallel, but using only one wire to the transformer and is using the radio chassis ground as the return for the heater supply to the transformer. I have never seen this done on any other radio and I am assuming its going to cause more mains hum than keeping the circuits separated. So I plan to disconnected one side of the 6 volt winding from the chassis and run two wires to the filaments in the convectional manner.
Just wondered if anyone had any thoughts or advise before I take the plunge. I have included a picture showing the original circuit and also the valve base. The brown pen marks show the existing heater arrangement as I find it. If I do rewire the heaters does the sequence I wire the heaters in matter at all. Should I start at the frequency changer or the output end on the valves line up.
As always thanks in advance for the helping hand from those more knowledgeable than myself
Thanks Regards Chris
Last edited by AC/HL; 21st Jul 2020 at 8:30 pm.
Reason: Non copyright circuit substituted
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