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resistance values

Posted: Wed Jun 22, 2011 4:01 pm
by sevrien
Hello, due the problems I have , written over here
http://www.mmoc.org.uk/viewtopic.php?f=4&t=38798

I bumped into this site
http://mgaguru.com/mgtech/ignition/ig106.htm

Its for MG dizzies, but I wondered if it could be applied to a sidevalve too.

It says that the Ohm value should be 50 megaOhm or more between the small lead to the dizzy and the block with points open.

Points closed you should read about 250 milliOhm

after checking this, I read 250 mil open and closed.

Is this a short circuit somewere or a bad condenser in the dizzy, or something else?

greetings.

Re: resistance values

Posted: Wed Jun 22, 2011 4:12 pm
by bmcecosse
You obviously have a short in the dizzy - points not opening (but you say they are) or incorrectly fitted so they are shorting to earth - or the 'low volts' wire has worn insulation and is shorting, or the capacitor has an internal short.

Re: resistance values

Posted: Wed Jun 22, 2011 4:23 pm
by sevrien
Points do open, so that's cancelled
there's no wiring exposed as far as I can see.
So it has to be the condenser.

Thanks

Re: resistance values

Posted: Wed Jun 22, 2011 5:12 pm
by bmcecosse
To test - disconnect the condenser and measure again.

Re: resistance values

Posted: Thu Jun 23, 2011 6:47 pm
by sevrien
Replacing the rotor with a well insulated red rotor cleared the problems.

But for the weird Ohm values, I blame it on bad measuring skills

Re: resistance values

Posted: Thu Jun 23, 2011 8:05 pm
by bmcecosse
:o :roll: :-?