Radex 1503 geiger counter troubles

JonIverson, Tue Feb 16 2021, 08:38PM

I've owned the Radex 1503 for a number of years. It has seen little use, but when it has, it has preformed well... that is, up until recently. Lately when I turn it on, it often goes into a constant rapid beeping. If I shut down and start again, sometimes it's back to normal, sometimes not. Also, even if it does seem to operate normally, sometimes at random counts (beeps) will start to suddenly increase for no reason and get almost constant where I just turn it off.

Any ideas on troubleshooting this welcome. So far, I have bypassed the geiger tube and tested it with an external meter and HV power supply. It runs fine. I also tried a fix here but didn't help: Link2

Thanks in advance for any help.
Re: Radex 1503 geiger counter troubles
radhoo, Fri Mar 08 2024, 07:47PM

It might be that one or both tubes are entering cascade, as a result of a defect preventing the quenching mechanism.

Your best bet is to replace the tubes.

If you cannot do that, there is a small chance the compensation capacitor can be increased. Not sure about the Radex design, but you should be able to locate that particular part based on this info: Link2