Originally posted by karro "Compatible external strobes include the AF540FGZ, AF360FGZ, AF200FG, and AF160FC."
which, in essence means, that any pentax-compatible (including third party) flash should work fine.
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.