View Full Version : miller big 40 problems
10-02-2006, 11:43 PM
hi i have a old miller big 40 that has been sitting up for a year or so. i got it back up and running good. but it wont arc or the 120v plug in wont work now . it has :confused: :confused: me . but i am going to start with the brushes. any responses will be appreciated. thanks matthew
10-06-2006, 05:03 AM
Seeing your reply in another thread, ... do a little digging around with a GOOD volt/ohm meter. Get on Miller's website, armed with the serial number for your machine, and you can get a owners manual for it. They also have the schematic for it. I looked at one, but it *could* be different from your machine, if they made any changes between years.
I'd have to venture a guess that brushes are a culprit here. Just a wilda$$ guess though.
10-06-2006, 10:23 PM
sound like its lost its magnetism which is the electrical charge left on the amateur after the machine is shut off it stores this energy to build off when re started if this is it it needs to be re excited by applying 12 volts to it i had this problem with a trailblazer 250g i had 7 yrs ago and it had the same symptoms your describing good luck
10-11-2006, 07:25 PM
check the dc voltage at the brushes. if there is no voltage present when running, check the alternator output. If the altenator is not putting out 35 volts dc it is probably bad. you can get one at a local auto parts store for less than $100.00.
10-11-2006, 08:00 PM
On my big 40 one of the long resistors burnt out due to corrosion.the resistors are under the gas tank.
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