540i Chain Brake Engaging on its own.....?

[HumBurner]

So, I've put some hard time on a 540i over the last 16 months. Running it, often, as if it were a 346/550, pushing it to its limits.

A few weeks ago I noticed the chain would rev over the chain brake at times. The brake handle is flimsy by design, and can engage when it rolls over on the ground. Okay, whatever, I'll live and deal.



Wore out the three chains, finally, and swapped sprockets.

I removed the drum and cleaned out all the insides. Worm reinstalled. Cleaned the brake band and all areas of the drum by hand. No burs, gouges, etc.


Now, the brake wants to engage, or at least the saw is sending an electronic signal to stop the motor, as I can still move the chain by hand when it stops the crank and flash its warning light at me.

Releasing the brake sometimes works, other times the warning light glitches, and sometimes it releases, then messes right back up.

The band itself doesn't seem to be engaging when this happens, yet the signal kills the crank. The band isn't broken or warped.

I haven't checked the elbow and spring yet. This SEEMS more like an electronic/signal issue than a physical issue.



Has anyone else encountered this or heard of this?

 

[cscltd]

check The connection under oil tank the activates the switch, have to split unit and remove oil tank, it may be loose. Plus check other ones too
or may need a new upper control panel-the one with the lights on it.

 

[HumBurner]

check The connection under oil tank the activates the switch, have to split unit and remove oil tank, it may be loose. Plus check other ones too
or may need a new upper control panel-the one with the lights on it.

Much thanks for the reply!

Oi, I hadn't planned on having to dig into this saw! Do the case bolts in this saw still need red thread setter, or will blue suffice? I'm running low on both, lol.

 

[cscltd]

they are plastic thread, no locktite
just make sure screw goes into original thread by backing screw till you feel it drop into thread and then tighten

 

[HumBurner]

they are plastic thread, no locktite
just make sure screw goes into original thread by backing screw till you feel it drop into thread and then tighten

First of the plastic saws I've had to think about, with some 350's/53s on the docket. Thanks for the tip.


Well, I got lucky so far. Didn't have to split the saw apart yet. Discovered there is no elbow for the brake, instead it has a sliding arm made of two connected pieces.

The arm wasn't sliding all the way to the top of its groove. Short tests seem to show normal function. Probably a matter of time before something malfunctions again.

I could see a plug, presumably for the brake, and it was not loose. The brake spring may need sooner replacing, but I'm going to give it a chance.

 

[HumBurner]

they are plastic thread, no locktite
just make sure screw goes into original thread by backing screw till you feel it drop into thread and then tighten

Do you know if I can disconnect the brake sensor, reassemble, and run the saw? Or will not having that sensor connected not allow the motor to run?

I was about to take it apart, but this seemed like a crucial question prior to having to disassemble twice.


Thanks

 

[HumBurner]

Nothing felt loose, but I cant believe how much debris is able to make it inside the electronics. With buildup making its way on and into the clips, it's most likely debris making contact and interfering with the signals.

Once the frost lifts, I'll gently blow out all the nooks and crannies and try reassembling with the brake/sensor hooked up.

If it still acts up, I'll see if the unit can run without being hooked up. If not, we're looking at $s to get answers.

 

[HumBurner]

Preliminary usage suggests the problem is resolved. I blew the hell out of the internals. Cleaned up the connectors and reinstalled all sensors/wires.

I'm leaving the chain brake off for now. The brake will inevitably get nudged tomorrow, and I'll see how it responds. If it seems like the issue is completely cleared up, I will reinstall the brake components.