JD6910 PTO won't engage.

[Bill Turtle]

I have been using my 6910 on a power harrow drill without a problem.
Today I put it on a round baler which entailed changing from 100 to 540 Pto speed. When I got to the field and turned on the Pto the orange warning light for the pto just flashed all the time. That is what usually happens if you turn off the tractor leaving the pto switched on. When you restart the tractor the light will falsh until you knock the pto off and back on.
I checked the fuseF113,f111,f114 all ok. I tried changing the yellow pto switch, which also made no difference.
Anyone any more ideas? Is there a relay I can swap over?

 

[agrimax]

Is the alternator charging correctly?

 

[Ioan annwyl]

Swap pto coil with one on diff lock or 4wd, to determine if coil is at fault otherwise change pto valve to newer type.

 

[Gerbert]

Try powering the PTO directly to the wires coming out the backend above the stub. Mine doesn't want to engage every now and then as well. Have been told that it could be a loose connection on a PCB.
I've been meaning to get it fixed but no time so till then I have connected it directly with a different switch. It throws up another error but it works.