I need help troubleshooting a problem with the charging system. This is a 53 Chevy 1/2 ton with original everything and 6 volts. It was working fine up until today. It had sat for a week. Cranked a little slow, but it usually does after sitting that long. Started, but the ammeter didn't go over into the + side like it usually does for a while until the battery recharges. Six miles to work and needle didn't move off center. At idle it showed a slight discharge as usual, and the directionals were slow blinking. I checked the belt and it's not slipping. CHevcked for obvious broken wires. Tapped the voltage regulator but that didn't budge anything. According to the manual, it could be anything from corrosion to a malfunctioning generator or regulator. Where do I start? I've got a multimeter, but electricity isn't my strong suit and I don't want to fry anything. I'd appreciate some help.