The guy that designed this circuit forgot to consider base-emitter breakdown. For Vcc>≈1.5*Vbreakdown, the timing will be altered by the breakdown.
If the trigger is capable of providing a lot of current in the high state, and the high state voltage > 2/3 Vcc, the transistor and/or the 555 and/or the source may be damaged. My bet is on the transistor.

What I posted was pulled directly from a Signetics Data Sheet Manual.

 

The guy that designed this circuit forgot to consider base-emitter breakdown. For Vcc>≈1.5*Vbreakdown, the timing will be altered by the breakdown.
If the trigger is capable of providing a lot of current in the high state, and the high state voltage > 2/3 Vcc, the transistor and/or the 555 and/or the source may be damaged. My bet is on the transistor.

Ron, I really didn't grasp what you were saying because you have a decimal point up there. The Vebo for the 2N3906 is 5V, so I'm assuming that you're questioning his use of Vcc= 5 to 15V?

 

Ron, I really didn't grasp what you were saying because you have a decimal point up there. The Vebo for the 2N3906 is 5V, so I'm assuming that you're questioning his use of Vcc= 5 to 15V?

The decimal point in 1.5 means "one point five". Unfortunately, it was a brain fart, so your confusion is justified. I should have said, "If Vcc is greater than the breakdown voltage, the timing will be altered by the breakdown.".

I stand by my second paragraph:

If the trigger is capable of providing a lot of current in the high state, and the high state voltage > 2/3 Vcc, the transistor and/or the 555 and/or the source may be damaged. My bet is on the transistor.

This is because the discharge pin turns on when the emitter reaches (2/3)*Vcc, so there is a high current path from the trigger source to GND, through the base-emitter "zener".

Is the Signetics circuit the same as the one I referenced?

 

The circuit referred to by Ron H does not mention any restriction on the pulse train, is it negative going or positive going or both.

I wonder if the circuit actually works on a positive going pulse train with a missing pulse.

 

The circuit referred to by Ron H does not mention any restriction on the pulse train, is it negative going or positive going or both.

I wonder if the circuit actually works on a positive going pulse train with a missing pulse.

It has to be a negative-going pulse. It should be narrow WRT the period, although the width can be taken into account when determining the RC time constant. A narrow positive-going pulse will be at 0V if a pulse is missing, holding the timing capacitor at 0.7V, so the missing pulse will not be detected.
Having said that, It won't work correctly if Vcc is greater than the base-emitter breakdown voltage.