Scr, gate to cathode = 0 ohms?? New one = 56 ohms

[fastline]

Trying to determine if this SCR is bad. I removed 2 of them. Measuring from cathode to gate, I get o ohms a o voltage drop in diode test in both directions. A new one tests at 56 ohms and .03V with a diode test in both directions. I am confused as to why a new one show does not show the diode test correctly and if indeed this SCR has a problem?

 

[Gary B]

A gate to cathode short is a fairly common failure mode for an SCR and results in the SCR remaining in the off mode. I was told that it is impossible for it to fail gate to anode but, I did encounter one once. It caused the SCR to conduct on every positive cycle. I haven’t done a ohm test on one for so long I don’t remember if minority carriers will give a weird reading or not.

 

[fastline]

Thanks a bunch for the reply. I did replace the SCRs and further found the driver resistor to be toast as well. After replacing that, I am happy to report that my circuit is humming and making smoothies.... (Blentec blender)