Then I g
ot to thinking, I have a Vivitar 5600 flash with a PM/N module. This module is for a Nikon EM or FG. Maybe I could connect a 1/8" stereo cable into the module and get the Radiopopper JrX Studio to control the output of the 5600. So I ordered the RadioPopper JrX studio set. When I received it I then went and modified the PM/N module. Connecting the tip of the Stereo plug to X, the ring to Q and the sleeve to GND. Pluged it into the Radiopopper Rx and it didn't work. All that I could get was full power out when tripped.So I went searching on the web and ran across a reference to The Nikon / Nikonos TTL Flash Interface. The site talks about modifying a Nikon flash to work with various underwater cameras. One part goes into detail about the SP line and if left unconnected the flash will not function in TTL mode. But if a postitive supply via a resistor is applied to the SP line the flash thinks a TTL camera is connected. A resistor in the range 22K - 47K from SP to Rdy is usually sufficient.
So I modified the PM/N by placing a 33K resistor between SP and RDY pins, leaving the 1/8" stereo plug connected to Q, X, and GND.
The next three pictures show the inside of the PM/N module and the mods I performed.
The inside of the PM/N before mods.
Adding the 33K resistor between SP and RDY.
Adding the wiring to the 1/8th" stereo plug.
I plugged it into the RadioPopper RX, adjusted the Group A knob on the transmitter to the low position, tripped the the transmitter and the flash fired at minimum power. Adjusted the Group A knob on the transmitter to the high position, tripped the the transmitter and the flash fired at full power.
I am looking into the PM/N2 Module when I can get one. Also looking into the DM/N2 module which is for the 4600.
The cost for this mod was 20 cents for the resistor, $1.50 for the 1/8" stereo plug, and $15.00 for the Vivitar 5600 with PM/N off of ebay.
Hope this helps someone out there.
