Thanks for the EG&G manual. It did confirm some thing and clear up some confusion on my part.

First, in the troubleshooting section, under "Intermettent Flashes" the first thing mentioned is "Flashtube FT-118 at end of life, hard starting." This was indeed the case, as replacement with the Radioshack tube cured it. I did find a place on the internet with a real FT-118 for about $30.

Second, it was curious that the 10-3 position seemed brighter than the other two. My usual experience with almost all 'automatic' photoflashes for photography is that they use flash DURATION to control the light output. So I figured the brightest flash was the longest duration.

This was NOT confirmed by the circuit which shows the 10-3 circuit discharging through a 2 ohm resistor and the 10-2 circuit discharging through a 50 ohm resistor. So the discharge through the 2 ohm resistor IS Faster, but it also burns the lamp brighter.

This is all confirmed in the manual:

10-2 light output = 800
10-3 light output = 4000
10-4 light output = 70

Therefore the need for some special filters to even things out.