D-104 wiring in PTT Viking II

[AF9J]

OK people,

I need some feedback.  If I have some time tonight (after writing a letter of recommendation for a summertime employee I supervised, who is applying for a nursing scholarship [she's going to school to be a Nurse Practitioner]), or tomorrow, I'd like to rewire the almighty D-104, for use with my Viker.  The thing is - I know that the shield of the mic cable goes to the shield, but does anybody know (so I can avoid trial and error), which pins the other two wires go to on a Viking II with the PTT mod? 

73,
Ellen - AF9J

[WQ9E]

Ellen,

Given the other goofy stuff in your Viking II the safest and surest bet is to see which mic connector pin shows about 22K of resistance to pin 1 (the control grid) of V-1 (the first audio tube).  The "standard" for other Johnson radios using that type of connector is pin 1 for audio and pin 2 for control but I wouldn't rely on the "modifier" in this case.

Rodger WQ9E

[AF9J]

Thanks again Rodger.

Ellen - AF9J

[WA1GFZ]

The stock V2 was not set up for PTT. The PTT models had a relay under the chassis. My V2 CDC also had a solid state positive rectifier and cap off the bias winding making about  +100 VDC to the PTT relay coil. The PTT switch on the mike switched the other side of the coil to ground. You will also need an antenna change over relay on the back. The crystal socket on the back provides 115 VAC when the TX switch is flipped of the relay is closed. the PTT relay has 2 sets of contacts to go across the TX switch contacts. So either the relay or TX switch put the rig into tx. The Switch is used in CW mode.

[AF9J]

The relay coil is installed under the chassis.  I plan in getting my hands on a sptt relay, so I can mute my receiver, T/R switch, and key my VFO.  I just need a drilled for connectors) box to hold the relay.  I don't have the tools to drill out a project box.

73,
Ellen - AF9J