GS-1100 - less than 600 volts?

[Geoff]

I have a detector from Far West Technology that I used to use with their portable spectrometer. I no longer have the spectrometer, but kept the probe as it's incredibly sensitive for a 1" detector. I'd love to use it for things like rain water and sea water, since it does great with low activity samples. The only problem is that 600 volts is too much for it. It operates best between 300 and 400 volts. Is there a way to get less voltage out of the GS-1100? I don't want to permanently reduce the voltage, My primary probe, a 20x110mm homemade monster, works best at 1050 volts. I'm not very strong in electronic theory, but I do have an IPC class III soldering certification. I'm more of a "work from a schematic" electronics tech. You tell me what to put where and I will make it look beautiful.

Here is the detector in question: http://www.fwt.com/hpi/hpi_5530ds.htm

[Sesselmann]

Geoff,

This is an easy mod, you can either do a permanent bypass or install a small toggle switch.

All you need to do is short the first 200V zener diode to ground, and the voltage drops by 200V across the board.

Steven

[Geoff]

Awesome, thanks for the quick reply Steven!