Using old hotshot flash

Even though I have a 430EXII, I'd like to use an old hotshot flash, a Kalimar SDZ-56, I've had for almost 30 years. I wouldn't want to risk damaging my DSLR so if it is usable, I would only use it with my Yongnuo RF-603 triggers. Is my old hotshot flash usable or should I junk it?

The major issue with old flashes is their flash trigger voltage, which needs to be <250V. Used with a radio trigger, it is a non-issue for camera itself.

I would think the high voltage might kill your receiver unit (check to make sure).
I'm running into voltage compatibility problems with my Vivitar 283's and radio trigger/receivers.

I keep hearing about the voltage in older flash units. My old flash runs on four AA batteries just like my 430EXII. What am I missing?

battery voltage itself is increased into the power capacitor for storage, for it to be sent to the xenon flash tube. the trigger voltage can be the very high stored voltage.

You'll be fine with the receivers, I've had some really archaic flashes that measured 9-14 Volts and my receivers are still doing fine.

You can test the voltage with a multimeter, which will run you $3-10 on eBay/Amazon.

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

only good source of flash voltage info i know of, and he only has a few of your brand flashes listed.

for me, this is a better safe than sorry thing. why put a cheap as hell flash on an expensive as hell camera? use a remote trigger or buy a modern cheap as hell flash.

DGStinner wrote in post #17406349
I keep hearing about the voltage in older flash units. My old flash runs on four AA batteries just like my 430EXII. What am I missing?

the energy from the batteries is stepped up to 300+ Volts and stored in a capacitor, which is then rapidly dumped into the xenon flash tube, creating a very bright arc for a fraction of a second.

modern flashes limit the voltage in the triggering circuitry (hotshoe) to a few volts, typically 3-12v but some older flashes don't, and the hotshoe sees the whole 300+ volts
this high voltage didn't affect old film cameras, with flash triggering designed to handle it, but modern DSLR cameras can be fried by the high voltage.