Hot source? Can't get a reading because it maxes out your rate meter? Try a 0.1 minute scaler reading, then multiply by 10!
This is a 100 µCi / 3.7 MBq Carbon-14 source disc, a pure beta emitter with a maximum energy of ~156.5 keV. The meter is a Ludlum 2221 scaler/ratemeter, and the probe is an LND 4335 proportional pancake tube in a custom enclosure I machined, running at 1600 volts with a threshold of 100 (10 mV).