So, new battery, starts right up, horn works, gas gauge works...h'mm, no brake light. No turn signals or nasty beeper. No headlight -- wait, low beam works. What the dickens?
Got out the schematic, scratched my head, measured battery voltage with engine running and engine off, a mystery. No common point of failure... It's impossible!
Remember what Sherlock Homes said? "Once you have eliminated the impossible, whatever remains, no matter how improbable, must be the truth." Or what the late Patrick S. Finnegan* told me about troubleshooting, years ago: "Start with the simple stuff and beware of pet theories!"
Checked the rear turn signals, easiest to get to: both burned out! Yep, I fried all the lights that were on, probably as the rectifier/regulator was trying to dump charge into the bad battery. And who knows if the rect/reg failed shorted -- I'll have to hang a meter on the battery and rev the engine to see.
Some of the lights are awkward to get to -- the instrument lights and headlight will require removing the windscreen and disassembling the "headset"to reach.
Update: On a rough check, the rectifier/regulator seems to be regulating with varying engine speed. So that's something.
* The best broadcast engineer I have worked for; and I have worked for some sharp guys. Pat was a no-wasted-motion man and that included his thought processes.
YANKEE RADIO TOOL KIT, #106
4 weeks ago