Vivitar 285HV
Flash overheating

by J. Beale  March 2007

The Vivitar 285HV is a workhorse flash unit which is normally very reliable. It is designed to run from 4 AA batteries (6 V total) but if you make your own adaptor to connect to the terminals in the battery compartment, you can run it from a larger external battery.  The dummy batteries can be made from wood dowels and the end terminals can be metal screws or even a part of a penny soldered to the wire. You can use external batteries with higher voltage, even a 12 V battery which makes the flash recycle about 3 times faster than with the regular AA pack.

This is useful when photographing children with fleeting expressions, for example. The flash will withstand this treatment if used for short bursts only.  I have done this sucessfully in several photo sessions, normally running the flash at 1/4 power.

What I did this time was take too many pictures in rapid sucession, and with the flash at the half-power setting. Specifically, with a 12 volt supply, I took 18 shots in 75 seconds; an average of 4.2 seconds apart. At this point the flash started visibly emitting smoke. Upon inspection, the HV output transistor was burned and broken open.   (Note that flash capactors retain high voltage and can be quite dangerous, so opening a flash is not recommend.)





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