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1991 Mark V won't run.
Posted: Sun Jul 26, 2020 4:49 pm
by Spooner
I just purchased (today) a 1991 Mark 5, 510 and never thought to plug it in and try it at the guys house when I picked it up. I got it home plugged it in, hit the switch and nothing. I took the terminals off and cleaned them and sprayed them with cleaner and still nothing. Not sure how to test the switch to see if it's the issue. The guy I bought it from said it was working fine the last time he used it in December.
Any thoughts or suggestions?
Re: 1991 Mark V won't run.
Posted: Sun Jul 26, 2020 5:20 pm
by garys
Check across the switch terminals with an ohmmeter. In the off position, it will show infinity. In the on position, it will show zero ohms if it is good.
Re: 1991 Mark V won't run.
Posted: Sun Jul 26, 2020 5:24 pm
by bainin
Do that test without the unit being plugged in please !
Re: 1991 Mark V won't run.
Posted: Sun Jul 26, 2020 5:39 pm
by Spooner
There are 4 terminals Garys... Which ones do I check? The two white ones?
Re: 1991 Mark V won't run.
Posted: Sun Jul 26, 2020 6:04 pm
by dusty
With it UNPLUGGED you can do a switch test across the two prongs of the AC cord.
Re: 1991 Mark V won't run.
Posted: Sun Jul 26, 2020 6:06 pm
by jsburger
Spooner wrote:There are 4 terminals Garys... Which ones do I check? The two white ones?
Check both sets. One set on each side of the switch. The side is the side that is parallel to the switch handle movement. Should be white white and black black.
Re: 1991 Mark V won't run.
Posted: Sun Jul 26, 2020 6:10 pm
by jsburger
dusty wrote:With it UNPLUGGED you can do a switch test across the two prongs of the AC cord.
But then you will get an unknown resistance reading across the motor winding's that may or may not be correct. Of course if you get a resistance reading that way the switch is working.
Re: 1991 Mark V won't run.
Posted: Sun Jul 26, 2020 6:36 pm
by Spooner
Yep figured it out. It is the switch. Thanks guys.
Re: 1991 Mark V won't run.
Posted: Sun Jul 26, 2020 7:54 pm
by JPG
jsburger wrote:dusty wrote:With it UNPLUGGED you can do a switch test across the two prongs of the AC cord.
But then you will get an unknown resistance reading across the motor winding's that may or may not be correct.
Of course if you get a resistance reading that way the switch is working.
Which IS the purpose, not taking a measurement.
However any <∞ and not very near 0 would indicate a switch(on) resistance problem.
Re: 1991 Mark V won't run.
Posted: Mon Jul 27, 2020 7:26 am
by garys
What style switch is on that unit? Is it the old toggle style switch, or is it the newer plastic flat switch. If it is the older switch, you can get a new one at Ace Hardware. Some stores don't keep it in stock so you might have to order it online.