Mr. Measures suggested there was a VHF parasite occurring leading to the arc.
I sent him a picture of the parasitics in this amplifier. They are constructed
of silver plated strap coiled around a couple large resistors with three turns
of the strap material. They are impressive looking even if they are
ineffectual. Allegedly the parasitics are too high Q for VHF in this
amplifier. So I am looking at applying a different form of parasitic
suppressors on the 3-500zg anodes which has a lower Q at VHF. The idea here is
the amp forms a VHF parasite which then jumps the band switch at the narrowest
gap. If anyone else would like a look see at the picture I would be happy to
send it to you. Mr. Measures has offered to send me a kit to replace the
parasitics, for which I am grateful. Especially if this will cure a long
standing issue with this amplifier. I have received the new band switch and
roller inductor tuning coil assemblies. It is my hope to iron out the problems
a
s I renew the top end of this RF engine.
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