[CFWhitman]

That conclusion does not make logical sense. Third party flashes are not clones of the four listed ones.

There were many "Pentax compatible" flashes made with high voltage contacts. Certain Vivitar and SunPak series were very popular, but their terminal voltages exceed 80V!

This posed no problem with pre-AF Pentax film bodies. The hotshoe contact was a simple mechanical switch triggered by a gear on the shutter mechanism. Voltage didn't matter.

With the advent of AF, the hotshoe became tied to the camera's CPU, either directly or indirectly. Suddenly, a flash signal greater than a few volts was enough to turn the camera into a doorstop.

When dealing with a third party flash unit, the only safe way to ensure compatibility is to measure the terminal voltage on the flash before attaching it to the camera - unless the box explicitly states compatibility with your specific camera.

Well, in principle that conclusion is correct. That is, any flash made for modern Pentax cameras should work fine. The problem is that just because it says it's for Pentax doesn't mean it's for modern Pentax cameras. There is a lot of older equipment still out there.

In this case I'm guessing that the flash is not a brand specific model but a generic manual flash. I would definitely measure (or possibly look up, but measuring is the safest bet) the voltage from the flash before I re-attached it to the camera. If it's low enough then it should be OK to use.

Of course, almost any flash can be used with a radio trigger off-camera, and that's a good way to get some of the best value and best results with flash anyway, though I don't see that as being a typical use case for a Q.

[RickS]

Here's an old list of flash trigger voltages. Maybe it will be helpful.

http://www.botzilla.com/photo/strobeVolts.html

Rick