At 00:28 3/16/02, you wrote:
Hi,
Thanks for the info on the OM-4. One question I forgot to ask, will
a Vivitar 283 damage the OM-4?
Mike
Mike,
There are two halves to this question:
(a) Whether the OM-4 (and a broader question about all the OM's) is robust
to strobes with high trigger voltage.
(b) Whether your particular Vivitar 283 runs a high trigger voltage; you
may already know the answer to this.
Perhaps John H. or Clint can discuss the design specs and how robust the
flash trigger electronics in the OM's are to old strobes with HV
triggers. I don't know how much the various ones can withstand.
About the Vivitar 283 (and the 285 also ??):
Whether or not it uses a high voltage or low voltage trigger depends on
when it was made. The "original" model has no TRIAC or SCR in the trigger
circuitry and runs a high voltage on the trigger contacts. At some point
in time (unknown to me) the circuitry was modified to a low voltage trigger
that is safe. If it's a "Made in China" version, it's low voltage. If
it's a "Made in Japan" version, it could be either. IIRC this should be
marked on the shoe somewhere.
If you have access to a _high_impedance_ voltmeter with a scale in the 1000
Volt DC range, you can measure the voltage on the strobe contacts (this
shouldn't trigger the flash). Take care when measuring it that you don't
short the probes to each other or you'll have to let the flash recharge
(along with letting your eyes recover from the flash). Old strobes in
general were typically about 250-600 volts; the original Vivitar 283 in
particular was at the high end of this range. Unfortunately I can't tell
you which is "+" or "-" on the contacts.
-- John
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