default wrote in message
...
On Mon, 9 Jan 2006 13:56:22 -0000, "Barney"
wrote:

I am having problems with an old (H reg) Vauxhall Cavalier. Basically it
won't start - there is no spark. These have a fairly basic electronic
ignition system which consists of a hall-effect unit in the distributor,
an
electronics control module, a darlington power transistor amplifier and a
coil. What I need to check first of all is if there is any output from
the
hall-effect unit, but I have no means of doing this. Anyone got any ideas
about signal levels coming out of this, etc, or any other ideas about
checks
I can make without much in the way of test equipment?


I have a hall effect pickup on my truck's speedometer. It is three
wire. Has +5 volts to one terminal, ground on the other and the
middle wire varies from +5 to ground as the rear wheels turn. It is
on the differential. Identical device on the drive shaft (anti-skid
input?)
--

Yes this is three wire too, but with a 12 volt supply - I think they usually
have a voltage regulator, so that the supply voltage can be anything from
about +3 volts to +24 volts. If the output is roughly a square wave from 0
to +5 volts I should be able make a simple tester for it quite easily.

Many thanks.