I have just acquired two old Prolinca studio heads which both operate on a half or full power switch. One head works perfectly but the other only fires on half power regardless of the switch setting. Any ideas on what could cause this?
I have another Prolinca head that I have had for years and this one had recently decided to only fire on half power and if this one is switched to full you can hear a slight 'tick' but no flash. Any ideas on that one?
Not familar with Prolinica, but studio flash power is usually controlled via banks of capacitors. The fact it has only two power levels would seem to indicate it has two capacitors and one has failed. That is not uncommon for flashes which have not been used.
The "tick" you hear may be the trigger circuit. In a studio flash the tube gap acts like a switch. A small trigger capacitor energizes the wire or shield around the tube which changes the state of the xenon in the tube and makes it conductive and that's what triggers the dump of the main capacitors creating the flash.
Caveat: The voltages involved can be lethal so DIY repairs are not recommended.
pr4photos wrote:
I have just acquired two old Prolinca studio heads which both operate on a half or full power switch. One head works perfectly but the other only fires on half power regardless of the switch setting.
When you say "head" do you actually mean a strobe head that connects to a power pack (AKA "generator"), or do you mean a self-contained monolight? (See photo below.)
In any event, Chuck's answer is almost surely the correct one: failure of one of the capacitors or its triggering circuit.
They are identical to the monolights pictured. I won't be taking them apart. Maybe letting the flash sit with the power on will reform the capacitor - seems some people on the net have had success with that
