SST 01 Rev 1

[Esprit]

heaveno Folks very new to this forum

After two years of uninterrupted service, Relay K2 fails to latch.
When power is applied the points continuously bounce, is there a fix.

[peranders]

First of all (if possible) use a 24 V source with current limitation. It's much safer not having live voltage.

Connect 24 V across the DZ1 zener or similar point. Start with T3 and go backwards. What is the base-emitter voltage on T3? Should be 650 mV and the collector-emitter voltage less than 200 mV.