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

Started May 21, 2012 | Discussions thread
RussellInCincinnati Veteran Member • Posts: 3,201
wait, attach/power RF603 transmitter directly to flash

Fabianbono, a further idea. How about using attaching a $20 dollar Yongnuo RF-603c transmitter directly to the top of the little Sony Nex flash ? And just skip the entire step of the bulky, $10 dollar, "TF-321 Canon E-TTL Flash Hot Shoe to PC Sync Adapter", that simply provides a mechanical hot shoe and pc cord adapter that the RF-603 already has .

  1. The NPShsa NexProShop hot shoe adapter costs $80 dollars, and you don't even get viewfinder-brightening with it, because the the NPShsa doesn't "look like a flash" to the Nex.

  2. There are many folks who would be very happy with modifying a $40 dollar Sony Nex flash to make it into a radio transmitter that doesn't flash at all. That's the main insight here, what's wrong with destroying a $40 flash to make it serve as a hot shoe adapter, if you were willing to pay $80 for a NexProShop adapter anyway?

  3. Yongnuo RF-603 transceivers only cost around $20 dollars.

  4. The RF-603 has an on-off switch that could serve the same function as the Sony flash hinge-on-off switch.

  5. RF-603 can probably run fine off of a tiny bit of 5 volt POWER.

  6. Pin 7 on the 14-pin proprietary Nex flash connector is 5 volt POWER.

  7. RF-603 itself comes with a hot shoe on top, and a pc sync cord output on its side. Plus it of course serves as a cordless radio trigger anyway.

Here's how we'd do it:

  1. Disassemble Sony Nex flash.

  2. Discard flash hinge switch and hinge springs. After all, we're going to permanently glue the flash hinge into some single position. Probably glue the flash hinge so that the flash is always "down".

  3. Discard flash tube, the light output device. This "flash" is going to be just a radio transmitter now, it will never emit any light again.

  4. Replace main, big Nex flash capacitor with a tiny one of same voltage rating . "Big" (percentage wise) weight savings here. Now the modified "flash" will never drain any power to speak of, nor will it take any time to "recycle".

  5. Disassemble RF-603 transmitter.

  6. Cut off the input wires from the bottom hot shoe of the RF603, they are going to be instead soldered directly to the output wires of the modified flash described below.

  7. Throw away the RF-603 batteries, we're going to power it via the 5 volts on the Nex flash pin 7. Wow, now the RF-603 weighs only 38 grams.

  8. Do the RF-603c remote flash trigger modification we both know about, that I described painstakingly here: Really all this modification does is run 5 volts through a 100Kohm resistor to J6 in the RF-603. But the 5 volts now can come from pin 7 of the Nex flash unit. The RF-603 transceiver will now function always as a transmitter.

  9. Disconnect the RF-603 leads to the RF-603 on-off switch, and tie them permanently together. We don't need a separate on-off switch for the Yongnuo transmitter, it will come on whenever we power up the modified "flash".

  10. How do we power the RF603 now? Using Nex port pin 7. The routing of pin 7 power will be first to the RF603 on-off switch, which we just disconnected above.

  11. From the output side of the RF603's on-off switch, we route a little bit of power through a 100K resistor to RF603 J6 point.

  12. Another power lead branches off from the RF603 on-off switch, to serve as the main power source for the RF603.

  13. A final power lead goes from the output side of the RF603 on-off switch, to just beyond the now-disconnected hinge switch in the flash, to become the main "flash" power as well.

  14. inside the now-empty battery compartment of the RF603, put all resistors, transistors etc needed to implement your Sony flash mod. But the output wires, the outgoing trigger signal, from that flash modification will connect into the very nearby "bottom hot shoe input wires" of the RF603, that we had cut off from the bottom hot shoe already above.

  15. Glue 40-odd-gram RF603 directly to top of casing of modified Sony flash. Too bad we can't easily remove the bottom hot shoe from the RF-603 (or maybe we can, haven't analyzed this, it's not important in any case. Pun intended.).

Result is a Sony Nex flash, lightened without flash tube or big internal capactor, permanently set into the compact "down position", with a Yongnuo RF603 permanently glued atop it. The RF603 providing a standard PC sync hot shoe atop it, a standard PC sync cord output on its side, and the thing is putting out a radio remote flash trigger as well that will be "automagically" picked up by other $20 dollar unmodified RF603 transceivers. Whole thing neatly powered by the Nex main battery.

Since the RF603's are only $20 dollars, and heck you were going to pay $10 dollars for a little dead hot shoe adapter, this isn't a bad mod even if you don't use the RF603 as a radio remote flash trigger.

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