DIY Vivitar trigger voltage modification

b1gdaddy wrote in post #4542887
Oh s**t yea I forgot the disclaimer..........

Time to worry about a call from 1-800 ava rice

SolidxSnake wrote in post #4434907
Also, make sure you pull out those batteries next time you pop open that flash. Wouldn't be fun to slip up and catch a shock from that capacitor... pretty lethal

I'll regard that as a disclaimer to anyone who wants to try this: If you don't know what you're doing, don't try it with a flash, it's too dangerous.

Danger:
Pulling the battery will not remove the lethal electric charge which is within the power capacitor of a flash

The power capacitor will hold charge, as demonstrated by SlikXSnake's experience

--wilt (who has replace 12000v voltage circuitry from inside tube TV --yes, I am that old -- as a teen, under an uncle's trained supervision)

A quick and drity way of discharging a flash capacator - fire the flash (after removing the batteries) then dap a screwdriver across the flash contacts. There should be a loud crack as the electricity arcs but done once it should not damage the capacator.

Lick the capacitor? Ok- if you guys say so.

*edit* That was a JOKE - I would hate for someone to actually think I was serious. I understand the capacity of that thing, from working with multiple farad high-output capacitors in the car audio industry but someone else may not. This ain't no 9-volt alkaline.

Ok- I need an assist - I am about to begin the transformation, and in the disassembly process, when splitting the upper and lower halves - this fell out. Anyone have a clue where it goes, I don't remember seeing it yesterday, and I'm not seeing anywhere that it "seems" like it should be.

HOSTED PHOTO
please log in to view hosted photos in full size.

adrenalnjunky wrote in post #4550228
Ok- I need an assist - I am about to begin the transformation, and in the disassembly process, when splitting the upper and lower halves - this fell out. Anyone have a clue where it goes, I don't remember seeing it yesterday, and I'm not seeing anywhere that it "seems" like it should be.

Goes on the hinge with the metal clip, one on the top and one on the bottom. It clicks the flash between the different angles. There's also a spring there (metal spring, flat metal angled plate sort of thing).

thx - I never pulled the 2 back pieces of casing apart in my dry run - that's why I vere saw it. In the middle of my soldering and whatnot, I managed to snap a contact off of my optotriac, soooo, I'll grab another tomorrow if the business is open, if not, looks like after Christmas. Everything else is pretty much reassembled, although I can 't use/test it until I get the rest of the circuit built.

A quick question:

Does this circuit also affect the PC Sync socket of the flash? Or only the hot-shoe. If it only affects the hotshoe, could I remove both the hotshoe and PC Sync cables and run them in parallel with this circuit with no ill effects?

You could just buy a Safe Sync. They slide into the hot shoe between the flash and camera and reduce the voltage. Some also have a pc outlet on them for those that don't have one on your camera. The rebel series don't have them.

Sledhed wrote in post #4576273
You could just buy a Safe Sync. They slide into the hot shoe between the flash and camera and reduce the voltage. Some also have a pc outlet on them for those that don't have one on your camera. The rebel series don't have them.

I'm sure I can buy the few parts for this circuit for much cheaper than a safe-sync. Plus, it's all internal as well, no extra bulk.

And why would I ever turn up the chance to rip something apart?

SolidxSnake wrote in post #4574208
A quick question:

Does this circuit also affect the PC Sync socket of the flash? Or only the hot-shoe. If it only affects the hotshoe, could I remove both the hotshoe and PC Sync cables and run them in parallel with this circuit with no ill effects?

Sorry I can't help you here as the gun I modded had a broken sync socket so I did not even consider it. I have given the flash back to it's owner but I will borrow it to check if need be.

Sledhed wrote in post #4576273
You could just buy a Safe Sync. They slide into the hot shoe between the flash and camera and reduce the voltage. Some also have a pc outlet on them for those that don't have one on your camera. The rebel series don't have them.

Cost of Wein Safesync $49/£45, total cost of parts to mod $10/£5 & as SolidxSnake says All parts are internal, plus you get to rip your kit apart . The whole point of sharing this mod was to save money & restore old equipment to use with todays technology. Wein products seem over priced to me & troublesome to many!.

I didn't post it to start an argument and say you were wrong, I did it so others that are not competent enough with their electronic hacking skills know that there is an alternative. I have an older set of Speedotron Strobes, they still work great. Even though the trigger voltage is below the pc sync voltage on my cameras, I still have a safe sync on the power supply. It's just cheap insurance.

Here is a good resource on older flashes and trigger voltages.

http://www.botzilla.co​m/photo/strobeVolts.ht​ml

Sledhed wrote in post #4577204
I didn't post it to start an argument and say you were wrong, I did it so others that are not competent enough with their electronic hacking skills know that there is an alternative. I have an older set of Speedotron Strobes, they still work great. Even though the trigger voltage is below the pc sync voltage on my cameras, I still have a safe sync on the power supply. It's just cheap insurance.

Here is a good resource on older flashes and trigger voltages.

http://www.botzilla.co​m/photo/strobeVolts.ht​ml

The best way to measure for the Vivitar ones though, is to measure with a multimeter. The 283s have huge variations from 5v to 300+ volts for triggers. Mine is around 103vDC so I can use it no problems with the PC sync but not the hotshoe of my camera.

I just finished modding mine - I tried for hours to fit the components of the circuit into the lower body of the 273, but it just wasn't happening - I even managed to almost destroy the light sensor. After some very delicate resoldering, I started over and moved the optical isolation circuitry into the flash head of the unit. Ran my wiring and still had to play with everything to get it all just right. Now I'm measuing 4.84 volts at the shoe, and it works fine with my XT.

If I were doing this again, I would probably breadboard the circuit, and come up with some small lo-profile external housing that could be glued to the housing itself, just for simplicity's sake. If the 285 and 283 have a good bit more room - than it might be a moot point.

Now I just have to figure out how to properly use it. I've done no reasearch/reading on how to shoot with a flash of this type, especially one that doesn't interface with the camera's onboard processing. Any tips there would be wonderful.

adrenalnjunky wrote in post #4580130
I just finished modding mine - I tried for hours to fit the components of the circuit into the lower body of the 273, but it just wasn't happening - I even managed to almost destroy the light sensor. After some very delicate resoldering, I started over and moved the optical isolation circuitry into the flash head of the unit. Ran my wiring and still had to play with everything to get it all just right. Now I'm measuing 4.84 volts at the shoe, and it works fine with my XT.

If I were doing this again, I would probably breadboard the circuit, and come up with some small lo-profile external housing that could be glued to the housing itself, just for simplicity's sake. If the 285 and 283 have a good bit more room - than it might be a moot point.

Now I just have to figure out how to properly use it. I've done no reasearch/reading on how to shoot with a flash of this type, especially one that doesn't interface with the camera's onboard processing. Any tips there would be wonderful.

Hmm... I wonder if you could fit the components in the hotshoe itself. That would make things very easy. I'm sure you could take R1 and solder it inline either inside the hotshoe or inline between the hotshoe and the bottom of the body. As for the rest, I'm sure I could find plenty of room in my 283.

It's all about the ghetto