I was having intermitent loss in charging on my 92 Saab 900 convertible and when i ran the tests in the Bentley manual it seemed that the alternator had gone bad. I had the alternator rebuilt with a new voltage a regulator, brushes, and commutator (which were heavily worn). Installed it and still no charging. the exciter wire is only putting out 5.6 volts and the battery light is always dimly lit. The battery is fully charged when i made these checks. Im not sure if this could be related but the day i started having trouble with charging i installed new front 60 watt speakers.