[Johnson] Johnson Adventurer/122 VFO power question

[SX-25]

     I just recently added a Johnson 122 VFO to my Adventurer. I am curious if anyone can weigh in with their speculation on what the original intent of Johnson was by introducing the 122 to its product line? Although I do not own a Viking I,  I am wondering if the 122 was designed as an adjunct more for the Viking I than as an upgrade for Adventurer users? Not having a Viking I schematic I have no idea of whether it was more readily suited to adding the VFO.

     My first discovery was that the  octal socket on the back of an Adventurer does not supply the necessary voltages. The 122 requires 250-300 VDC for B+ and my Adventurer only supplies plate voltage for the 807 at around 550 VDC. Obviously I could have added dropping resistors but  then throw off the parameters of the plate supply. Since I wanted the 122 also useable with several other 50s/60s vintage transmitters I own,  I built a separate power supply to fix the voltage problem and it works very well.

     But I am wondering about this. Why wouldJohnson sell a VFO that was incompatible with its Adventurer? Surely bucket loads of novices advancing to their general class license in the Korean War era stayed with their li'l Adventurers (at least for a while) and added the VFO pursuant to their new privileges and were looking for that correct B+ voltage by way of the Adventurer octal socket. After all, Johnson provided everything else needed in the octal socket, filament voltage and keying  circuit. Also, most external VFOs of the era required that same voltage for B+; they pretty much all need 300 VDC and 6.3 VAC. 

     Quite frankly, in spite of Johnson equipment being top of the line, I feel their instruction manuals are terrible and in many ways are too nebulous to be of much help. In concert with this, my Adventurer does not have its original transformer, so quite possible there was some scheme that precludes direct use of MY Adventurer with a 122 VFO.

     Thoughts?

     73 and Happy New Year to all. Keep 'em glowing. They make the nicest sounding CW on the air today!

     Vern WA9VLK

     
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