Success PC Port output on HVL-F7S (Sony NEX) without PREFLASH!!!

Started May 21, 2012 | Discussions thread
OP fabianbono Regular Member • Posts: 190
Re: Success PC Port output on HVL-F7S (Sony NEX) without PREFLASH!!!

Tamaki wrote:

Dump Question (and then also in my bad english),

for what purpose is the 15k resistor? and where do you get the ground for the pc cord?

great mod, i like it

Hi Tamaki.

The couple of resistors 5K and 15K are to control the amount of current used to trigger the transistor base. it is a basic electronic configuration.

Actually the 15K value should be a little higher, like 47K, to reduce the current drain to ground.

All the GND is same in all the circuit, and I took from F7S flex PCB, as you can see on pictures.

Check the picture just under the circuit, and you will see a cable sold near IC chip, that area is Ground. I follow the signal from connector to the circuit area.

That ground is OK to PC Sync Port, since just need to make a short-circuit between the two ends of the connector.

Usually inside the external flash unit you will have an optoisolator, or a transistor input then is ok to trigger by ground.

I hope in a couple of days receive my YN603 WLL triggers and a hot shoe, then I will build the V2 of this mod. For sure will post it later step by step.

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