Yesterday, I bought another "broken tool" from a yard sale.
A mid '70s Sears battery charger, "old and slow" the kid said. "It works but it shuts off and then comes back on." Hmmmm.
Three bucks.
Got it home and found it's charging with AC. 17V AC, 3V DC = broken rectifier. Shouldn't be any big deal to replace the diode bridge or build a new one and get it going again.
Cool piece, has chrome on it! Charges at 6V, 12V or 24V, heavy!
Got it open and found it was built by the LEH, Inc company, which is the same company that makes Lincoln Welders.
Never knew they also built chargers for Sears.
Certain I can get this going again. Cool item! I'll probably keep this thing.