My first 727 job was as a captain. My main interest was trying to figure out what the FE was doing, not ever having one before. One day I made him nervous by looking back at his panel and he asked what I was looking for. I said why do the left and center engines have 15 KW loads and the right one zero? He said the right engine light is not illuminated. I asked him to press to test the light and the light was burned out so we took off with only two generators working.
A long time ago a 727 was lost at night taking off from LAX at night with two generators and another was lost overloading the final one and losing everything. That might have been the reason for standby instruments as we have now.
I don't think the Lears I flew had standby instruments. I recall one midnight departure out of DCA with Hollywood movie people on board when the lights on the instrument panel went bright and one generator dropped off line. I saw the voltage off scale so turned the operating generator off. The one that had kicked off picked up the load and voltage returned to normal 28 VDC. The next day I looked through our systems check list and nothing covered our problem that night. Maintenance found a cannon plug with a short circuit causing our problem. The high voltage may have damaged all of our systems if I had let it continue. I'm not saying this happened in their case but sometimes unusual things happen.