[TenTec] Power Supply Damage Control

[jessystems@cablespeed.com (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