Black & Decker CM 1936 -- "kill bar" doesn't work. Put key in starts up immediately.

MowerMike

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Re: Black & Decker CM 1936 -- "kill bar" doesn't work. Put key in starts up immediat

Interesting ! And, no, that is definitely NOT normal. For sure, that part needs to be replaced, but the question is what caused this to happen. It might actually be a fuse that has blown, and unless the root cause is determined, it will occur again. If the material is aluminum (non-magnetic), then it is probably a fuse. I don't see a fuse or other part shown in the parts list, so it is probably part of the switch assembly.

As to the ohmmeter readings, no reading is the same as OL or infinite resistance, indicating an open circuit. A low reading of ~1 Ohms indicates a closed circuit with some internal resistance from the wiring. From what you have reported, it sounds like your switch is operating normally.

At this point I would recommend purchasing a new switch assembly, and cross your fingers !

Also, you might try posting in the Black&Decker subforum under Equipment by Brand. You may find someone who is more familiar with your specific lawn mower.

Good luck !
 

1 Lucky Texan

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Re: Black & Decker CM 1936 -- "kill bar" doesn't work. Put key in starts up immediat

yeah, I don't see how that could be anything except a fuse. be careful and double check connections, look for pinched wiring, etc.
 

smhoff2019

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Re: Black & Decker CM 1936 -- "kill bar" doesn't work. Put key in starts up immediat

Thanks a lot, Mike and Lucky Texan,

It's hard not to pinch wires a little because they fit into a small space. So we did see a pinch or two, but don't know if any one of them was enough to blow a fuse. But the original problem happened before we ever opened up the control box. When you say "try a new switch assembly", you mean buy a new switch, right? The $16 thing that looked like a relay to my son.

We did also see one wire (black wire) that had like a dent or small gouge in it, with metal exposed inside, that we could wrap in electrical tape.

You're thinking that a short circuit is what would blow a fuse, right? Are you thinking that would crack the aluminum (?) piece that I took the photo of? Would hitting a rock be enough to blow a fuse?

So -- we look for a short -- and try a new switch -- is what you're thinking, right?

Thanks again -- I will also post to the Black and Decker forum.
 

MowerMike

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Re: Black & Decker CM 1936 -- "kill bar" doesn't work. Put key in starts up immediat

The part that you show in the attached photo IS the fuse that has blown. It is not broken so much as the material has melted due the extreme heat that is generated when excessive current passes through it. When I say to purchase a new switch, I am assuming that the fuse in the photo is part of it. And, yes, the switch is part number 2 in the parts list that your son thought is a relay. The cause may be a short circuit, but it could also be caused if the motor generated very high current due to sudden very high load. Did you or your son ever stall it out from hitting a stump or rock ? If the mower does not have a circuit breaker, then this could result in the blown fuse. My initial thought was that this may have resulted in the switch contacts fusing closed, but the fuse prevented this by blowing first. In any event, the best you can to is make sure all wiring is insulated and connections made to the correct terminal points. If the problem persists, then either take it to a repair shop or bite the bullet and buy a new mower.
 

1 Lucky Texan

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Re: Black & Decker CM 1936 -- "kill bar" doesn't work. Put key in starts up immediat

^^^^ that - precisely


just mentioning that, a possibility is that a wire in the harness was pinched or misplaced at the factory and has taken some time to abrade or cut thru 'enough' to actually short the system. Good job on the tape. Hopefully, no conductors inside were severed.
 

smhoff2019

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Re: Black & Decker CM 1936 -- "kill bar" doesn't work. Put key in starts up immediat

^^^^ that - precisely


just mentioning that, a possibility is that a wire in the harness was pinched or misplaced at the factory and has taken some time to abrade or cut thru 'enough' to actually short the system. Good job on the tape. Hopefully, no conductors inside were severed.

Thanks again, Mike and Lucky Texan. Switch came in the mail. My 10 yr old put it in. I think he forgot to use electrical tape on the wire that looked just a little bit iffy. But the mower is working fine so far. He used it, I used it for about 30 min. tonight. So far so good. I guess we should probably go back in there once more and tape up that wire? But so far so good. Thanks a million. This is great experience for him. And so far we've saved our mower, which is good for everyone.:smile:
 
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