My 740 t volt meter showes only 10 volts above 4000 rpm. this is at night with the headlights on, of course and the dash lights go dim also. Below 4000 rpm charge is 13-15 volts(in the middle of the gauge?)

Thanks for the help, found one brush very short and one slip ring very badly worn, I suspect the brush could not maintain contact a high RPM.
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PTR ,740 t -145-http://volvoadventures.com/220spec.html

Check the length of the brushes. Under 5mm = replace.

Good Luck,

Bob

:>)

PTR:

This is sounding like an alternator problem.

First do some basics though--check the connections at back of alternator. There's some good info on the FAQ here; that's also worth looking at.

This article is decent too:

http://www.misterfixit.com/alterntr.htm
--
Norm Cook Vancouver BC; 1989 745T 200,000KM

Start by checking for loose belt - or REALLY likely, bad mount bushings
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'73 142, '75 242, '75 245, '80 245, '86 244, '87 745T