[TenTec] Power Supply Damage Control

[Pete Juliano]

The Model 252 does not have an  IC regulator. It uses a zener diode and discrete  components to establish the voltage reference. It lacks a crowbar circuit for over voltage protection should the pass transistor blow. However it  has an SCR circuit for current limiting.

Nice supply for its time but dangerous to use without the crowbar. Ten Tec used to sell a model 1150 Over voltage Protection (Crowbar) circuit but no longer does. It has only 6 components but worth the time and $ to build -- sure prevents smoking the rig!

Pete W6JFR