resistor

blunted · Apr 18, 2013

i think i shorted out the resistor. can that happen? thanks.

rustred · Apr 18, 2013

on what??? harmon karden stereo... yes i have had to get some replaced.

Janicholson · Apr 18, 2013

(assuming it is the ballast resistor) A shorted resistor (to ground when the ignition is on) will burn out. The resistor on the lights will also smoke and burn out if shorted.
The Resistor used on the charging system (when no regulator is used) can also burn up. But it needs to be connected to a hot wire as it is grounded normally. Jim

John T · Apr 19, 2013

"i think i shorted out the resistor. can that happen"

Yes that CAN HAPPEN

Know what resistor you shorted?? Ignition Ballast Resistor (stand alone device somewhere between IGn switch and coil) or Light Dimming resistor (located on back of light switch)??

Did it short across itself i.e. became by passed orrrrrrrr did one end get shorted to frame ground???

Ifffffff you shorted across an Ignition Ballast she will run but the coil will get very hotttttttt and could eventually burn up and the also the points get burned,,,,,,,,,Iffffff the input (from Ign switch) of the Ballast got shorted to frame a wire would melt or a fuze would get blown,,,,,,,,Iffffffff the output (to coil) of the ballast got shorted to frame she wouldnt run and possibly some smoke due to an overheated ballast..

So yes it can happen and the consequences depends on which resistor was shorted,,,,,, and on which end,,,,,,,,,,,and to where

Their job is to drop voltage (say 12 to 6) and limit current to the downstream LOAD, be that an ignition coil (like a 6 votl coil on a 12 volt tractor) or the lighting circuit for DIM operation.

John T

blunted · Apr 19, 2013

i was checking spark in the points, and the dist. clip that holds the cap, and slid over to the batt side of the resistor. i mite still have a hard time getting juice to 4 and 2 cyl. on this C.il get another resistor to see first. thanks..

mkirsch · Apr 19, 2013

Last resistor we tried, we could only get 3V to the coil, even though there was 12.6V there without the resistor. I'm starting to think they're more of a pain than they're worth.

Used a 12V coil instead.

Bob M · Apr 19, 2013

A short to the battery side of the resistor could burn out the wiring between the ammeter, ign switch and ballast resistor. Or it can blow out the fuse, if there is one.

However a short there WILL NOT harm the resistor!

John T · Apr 19, 2013

I have observed ballast resistors in the 1.2 ohms range all the way up to over 2 so it can indeed make a difference. Ideally they should be matched to the coil so theres a 50 50 voltage divider with 6 volts dropped across BOTH the ballast and a 6 volt rated coil. Unless theres a need for the 6/12 ballast by pass system for improved cold weather starting I agree go with a 12 volt coil no dern ballast required

John T

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